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See all the wonderful things Eleni Paloumpa has made

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Timeline

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On our PC

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Trying Virtual experiments in nano-scale - On line

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Serial Dilution approach to nano-quantities

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Serial Dilution approach to nano-quantities

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Phet Colorado / Concentration

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Nano-Tech Science Education

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Waves and Dancing Ferrofluid

This experiment is aimed to provide an understanding of how the particles act in changing magnetic field. If there is no magnetic field, ferromagnetic nanoparticles are random. When we applied magnetic field around the test tube, ferromagnetic nanoparticles respond the field and the magnetic moments of particles align with the magnetic field lines.

LED (Light Emitting Diodes)

This experiment explores the physical phenomenon of LEDs, how they operate, their unique features, together with the characteristics of light. LEDs are environmentally friendly, ultra-efficient electronic (or semiconductor) lighting devices that emit cooler, softer and/or more natural light with relatively the least consumption of watts when electrical current passes through them.

Carbon Nanotubes

The carbon atom seems to be the most wonderful of all the elements in the periodic table. As well as being the basis of life, it is one of the most important building blocks of nanotechnology. Carbon nanotubes, composed of interlocking carbon atoms, are 1000 times thinner than human hair and can be 100 times stronger than steel. The amazing properties of carbon nanotubes provide many application areas.

Waveguide Fabrication by Sol-Gel

This experiment is aimed to provide an understanding of sol-gel, its products, including fiber optics used in the internet communication. Fiber Optics is a data-delivery system transmitting light and sound through glass fibers. In telecommunications, the fiber optic technology has replaced the copper-wire technology by delivering information 1000 times faster and 100 times farther.

Nanocamp Activity - Silver Mirror

The "Silver mirror" lesson explores the properties of silver and its compounds as well as its opportunity to be used as material for nanoparticles and their usage, and the history of mirrors and how can they be produced.

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This experiment is aimed to provide an understanding of how the particles act in changing magnetic field. If there is no magnetic field, ferromagnetic nanoparticles are random. When we applied magnetic field around the test tube, ferromagnetic nanoparticles respond the field and the magnetic moments of particles align with the magnetic field lines.

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Review, by  Leonard Bernas*, Kurt Winkelmann, Katherine Stewart, Carolyn Chabuz, Jean Rose

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Summary Students learn about the biomedical use of nanoparticles in the detection and treatment of cancer, including the use of quantum dots and lasers that heat-activate nanoparticles. They also learn about electrophoresis-a laboratory procedure that uses an electric field to move tiny particles through a channel in order to separate them by size. They complete an online virtual mini-lab, with accompanying worksheet, to better understand gel electrophoresis. This prepares them for the associated activity-to write draft research proposals to use nanoparticles to protect against, detect or treat skin cancer.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

Engineering Connection

Because nanoparticles are very good imaging agents, biomedical engineers are focusing on the use of nanoparticles in cancer diagnosis and treatment. For example, since gold nanoparticles absorb light and produce heat, they design infrared lasers to superheat the gold nanoparticle and destroy cancerous cells through heat. This application shows promise in breast and prostate cancers that are fairly close to the body surface and readily accessed by the laser light. By learning more about this field, students gain a better understanding of current biomedical engineering research, as well as potential solutions to real-world human problems.

Learning Objectives

After this lesson, students should be able to:

Define and discuss practical uses of nanoparticles and quantum dots in current biomedical research.

Complete a virtual laboratory to study electrophoresis, a commonly used laboratory tool.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS Performance Expectation

Click to view other curriculum aligned to this Performance Expectation

This lesson focuses on the following Three Dimensional Learning aspects of NGSS:

Science & Engineering Practices

Disciplinary Core Ideas

Crosscutting Concepts

Criteria and constraints also include satisfying any requirements set by society, such as taking issues of risk mitigation into account, and they should be quantified to the extent possible and stated in such a way that one can tell if a given design meets them. Humanity faces major global challenges today, such as the need for supplies of clean water and food or for energy sources that minimize pollution, which can be addressed through engineering. These global challenges also may have manifestations in local communities.

Suggest an alignment not listed above

Worksheets and Attachments
Visit [www.teachengineering.org/lessons/view/van_nanoparticles_lesson03] to print or download.

Introduction/Motivation

(Be ready to play for the class an online three-minute video, The Nano Song, at https://www.youtube.com/watch?v=LFoC-uxRqCg.)

We have studied how the destruction of the ozone layer in the Earth's atmosphere can lead to an increase in ultraviolet radiation intensity that, in turn, can drastically increase the risks and rate of human skin cancer. In this lesson, we are going to work again to answer our original challenge question:

What does the ultraviolet index information mean in terms of your potential skin cancer risk living as a surfing enthusiast in Einstein Cove? How could you use your expertise in nanoparticles to treat, detect, and protect against skin cancer?

By studying the nanoparticle concept and some current applications of these particles in biomedical engineering research, I bet that you have already started to generate some ideas for better preventing, detecting, and treating skin cancer caused by UV radiation.

Let's review: The term nanoparticle is used to refer to a particle with a diameter between 1 and 100 nanometers. Nano is a prefix of the SI system and is defined as one billionth of its base unit. Other ways to state this: 10 ⁹ nanometers equal one meter. 1 nanometer is 10⁻⁹ of a meter. 10 hydrogen atoms placed side by side equal the length of 1 nanometer!

SI prefixes.

(Show students The Nano Song video.)

The National Nanotechnology Initiative Committee decided that in order be classified as nanotechnology, the technology must meet three criteria. Nanotechnology:

1. involves research and technology development at the 1-100 nanometer range

2. creates and uses structures that have novel properties because of their small sizes

3. builds on the ability to control or manipulate at the atomic scale

Properties of nanoparticles differ in behavior from larger amounts of the same material. For example, a nanoparticle of silver, gold or iron has different properties than 5 kilogram amounts of the same substances. At the nanoscale, particle behavior abides not only by the physical laws of chemistry, but also the laws of quantum mechanics. You may recall (from the first lesson in the unit, Electromagnetic Radiation) that at the quantum level, both light and matter have a dual wave-particle nature.

Today we will take a deeper look at how biomedical engineers focus on nanotechnology in the use of quantum dots in cancer treatment, and we'll end the lesson by conducting a virtual lab!

(Continue by delivering the content in the Lesson Background section). Following the lesson, conduct the associated activity Nanotechnology Grant Proposal Writing where students apply the knowledge they gained through the unit to write research proposals about the use of nanoparticles to protect against, detect or treat skin cancer

Lesson Background and Concepts for Teachers

(Present the content below and discuss nanoparticles and quantum dots as a class. Then, have students complete the virtual electrophoresis lab at https://www.classzone.com/books/hs/ca/sc/bio_07/virtual_labs/virtualLabs.html. Each student needs access to a computer or tablet to complete the virtual lab.)

Lecture Information

One application of nanotechnology currently being investigated is the use of quantum dots to deliver cancer treatment to site-specific locations close to cancer tissue. A quantum dot is a semiconductor crystal that exhibits quantum behavior in optical or electrical processes. Traditional cancer treatment causes cytotoxic effects in both cancerous and healthy cells and thus patients may become sick and/or lose their hair and fingernails as a result of the treatment. With a site-specific cancer delivery system, these side effects are greatly reduced. Research is currently being conducted in which zinc sulfide (ZnS) quantum dots are coated with a polyethylene glycol molecule and a cancer cell-specific marker antibody. Then polyethylene glycol (PEG), which is a covalent organic molecule, is attached to the quantum dot to mask the quantum dot (QD) from the body's immune system. The PEG molecules also prevent the QD from delivering the cancer treatment to healthy tissue. Upon encountering the marker present on the surface of the cancer cell, the PEG is cleaved and the treatment is delivered.

A) The basic structure of a cadmium selenide quantum dot. B) A zinc sulfide-coated quantum dot. C) A quantum dot showing polymer and drug attachments.

After attaching the PEG to the quantum dot, engineers verify that the attachment has been successful. One way this is done is through electrophoresis. Electrophoresis is a method of using an electric field to move particles through a channel that then separates them by size. The particles move at a rate inverse to their masses; thus, larger particles are slower than smaller particles and do not migrate as far down the gel. By observing how the particles move in electrophoresis, biomedical engineers can confirm that the PEG molecule is attached to the quantum dot.

Quantum dots are also used for medical applications by taking advantage of their fluorescent properties. DQs can absorb light at one wavelength and give off light at another wavelength in discrete amounts (quanta), which explains the name "quantum" dot. By varying the particle size of the same quantum dot material, it can be made to fluoresce in different colors. The smaller the particle, the more its emission is blue shifted, and conversely, the larger the particle size, the more its emission is red shifted. This characteristic enables multiple factors to be tagged using the same original light source. The fluorescent quantum dots are tagged with a tumor-specific cell marker antibody and a polymer coating, and then are injected into the circulatory system. By a similar mechanism as described above, they primarily accumulate in the area of the tumor, which enables physicians to visualize areas of cancerous tissues and how they have metastasized.

In addition, gold nanoparticles have been designed to absorb light of wavelength slightly more than 800 nm. When coated with a tumor-specific antibody, these nanoparticles aggregate around cancer cells. Since the gold nanoparticles absorb light and produce heat, lasers of wavelengths in the infrared range are used to superheat the gold nanoparticle and destroy the cancerous cells through heat. This application shows promise in breast and prostate cancers that are located fairly close to the body's surface and thus readily accessed by the laser light.

Associated Activities

Nanotechnology Grant Proposal Writing - Students apply the knowledge they gained through the unit to write research proposals about the use of nanoparticles to protect against, detect or treat skin cancer. They present their proposals to the class for critique. The writing exercise demonstrates their understanding of the unit concepts and showcases their ability to communicate plans for specific nanoscale research that would generate a solution to the unit's grant challenge question.

Vocabulary/Definitions

bioactive material: A material capable of interacting with living tissues.

covalent bond: Atoms that bond sharing two electrons.

cytotoxic: Toxic to cells; kills living cells.

electrophoresis: A method of using an electric field to move particles through a channel and separate them by size. The particles move at a rate inverse to their masses; thus, larger particles are slower than smaller particles and do not migrate as far down the gel.

fluorescence: The property of some molecules to absorb a wavelength of light and then emit light at a higher wavelength.

nano: A Greek word meaning dwarf; one billionth.

nanometer: One billionth of a meter.

nanotechnology: Technology development at the atomic and molecular range (1-100 nm) to create and use structures, devices and system that have novel properties due to their small sizes.

quantum dot: A semiconductor crystal that exhibits quantum behavior in optical or electrical processes.

Assessment

Pre-Lesson Assessment

Prompt Question: Ask students: One of the things we will discuss today is gel electrophoresis. Has anyone ever heard of electrophoresis? How can it be used? How does it work? Do you think it could be used in a way that could help us answer our challenge question for this unit? (Expect that some students may have heard of the use of gel electrophoresis in DNA fingerprinting. Electrophoresis is a way to separate molecules based on their sizes and charges. The process works by applying an electric field, causing molecules to move; smaller molecules move faster, while larger molecules move slower.)

Lesson Summary Assessment

Virtual Electrophoresis Lab: Have students individually conduct the virtual lab at https://www.classzone.com/books/hs/ca/sc/bio_07/virtual_labs/virtualLabs.html, which takes about 15 minutes to complete. In the process, have students answer the questions on the Gel Electrophoresis Virtual Lab Worksheet based on the virtual lab. Review students' worksheet answers to gauge their depth of comprehension.

Additional Multimedia Support

The Nano Song video (3 minutes) at https://www.youtube.com/watch?v=LFoC-uxRqCg.

McDougal Littel's Virtual Biology Labs' gel electrophoresis virtual lab at the ClassZone website: https://www.classzone.com/books/hs/ca/sc/bio_07/virtual_labs/virtualLabs.html (takes about 15 minutes to complete)

An alternate gel electrophoresis virtual lab: Genetic Science Learning Center, University of Utah Health Sciences' Gel Electrophoresis Lab at: http://learn.genetics.utah.edu/content/labs/gel/ (takes 10+ minutes to complete)

References

Roco, Mihail C., and William S. Bainbridge (eds), National Science Foundation. Converging Technologies for Improving Human Performance: Nanotechnology, Biotechnology, Information Technology and Cognitive Science, Dordrecht, The Netherlands and Boston, MA: Kluwer Academic Publishers (Springer), 2003. http://www.whitehouse.gov/sites/default/files/microsites/ostp/bioecon-(%23%20023SUPP)%20NSF-NBIC.pdf

Frequently Asked Questions, National Nanotechnology Initiative. http://www.nano.gov/nanotech-101/nanotechnology-facts

Copyright © 2013 by Regents of the University of Colorado; original © 2010 Vanderbilt University

Contributors Michelle Bell, Amber Spolarich

Supporting Program VU Bioengineering RET Program, School of Engineering, Vanderbilt University

Acknowledgements

The contents of this digital library curriculum were developed under National Science Foundation RET grant nos. 0338092 and 0742871. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.

Last modified: June 20, 2019

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Nanotechnology and Cancer Treatments - Lesson

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Students learn about the biomedical use of nanoparticles in the detection and treatment of cancer, including the use of quantum dots and lasers that heat-activate nanoparticles. They also learn about electrophoresis-a laboratory procedure that uses an electric field to move tiny particles through a channel in order to separate them by size.

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STEM Curriculum K-12

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Summary Through three teacher-led demonstrations, students are shown samplers of real-world nanotechnology applications involving ferrofluids, quantum dots and gold nanoparticles. This nanomaterials engineering lesson introduces practical applications for nanotechnology and some scientific principles related to such applications. It provides students with a first-hand understanding of how nanotechnology and nanomaterials really work. Through the interactive demos, their interest is piqued about the odd and intriguing nano-materials behaviors they witness, which engages them to next conduct the three fun associated nanoscale technologies activities. The demos use materials readily available if supplies are handy for the three associated activities.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

Engineering Connection

Work in the emerging field of nanotechnology depends upon many classical materials engineering principles and fundamentals that stem from chemistry and physics. While engineers have been using ferrofluids for many decades, recent research has enabled new medical applications for them to become reality. Quantum dots are slated to drastically improve cancer cell targeting and other focused medical treatments because of their optical properties. Unique nano materials properties are also being applied to renewable energy solutions. Scientists and engineers have developed very efficient, size-dependent, optical beacons, and are designing biocompatible compounds. Gold nanoparticles are also suitable for numerous biosensing applications. Engineers are challenged to develop inexpensive fabrication processes for creating industrial amounts of such materials efficiently.

Learning Objectives

After this lesson, students should be able to:

Explain how nanoscience works as it pertains to real-world applications.

Describe how ferrofluids work, including a conceptual knowledge of magnetic requirements.

Describe how quantum dots work, including a conceptual knowledge of optical property effects due to quantum confinement.

Explain how gold nanoparticles interact with light and the effect of particle clustering on optical properties. Additionally, describe the surface charge and its effect on particle clustering.

Identify key applications and potential applications for specific nanotechnologies.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS Performance Expectation

Click to view other curriculum aligned to this Performance Expectation

This lesson focuses on the following Three Dimensional Learning aspects of NGSS:

Science & Engineering Practices

Disciplinary Core Ideas

Crosscutting Concepts

Communicate scientific and technical information (e.g. about the process of development and the design and performance of a proposed process or system) in multiple formats (including orally, graphically, textually, and mathematically).

Attraction and repulsion between electric charges at the atomic scale explain the structure, properties, and transformations of matter, as well as the contact forces between material objects.

Investigating or designing new systems or structures requires a detailed examination of the properties of different materials, the structures of different components, and connections of components to reveal its function and/or solve a problem.

Suggest an alignment not listed above

Pre-Req Knowledge

Students must be familiar with nanotechnology and some of its applications. For a good overview, conduct the related lesson, Nanotechnology as a Whole, to impart an introduction to nanotechnology and a conceptual understanding of the nanometer scale. In addition, students must be proficient in algebra. And, having an introduction to physics and chemistry concepts is helpful.

Introduction/Motivation

A 3D axial view looking down the center of a carbon nanotube model.

(To engage and motivate students, open with a few short demonstrations that relate to the three associated activities. See the materials lists and instructions for three example demonstrations below; modify them as needed. Allow approximately 15 minutes for the demonstrations.)

Ferrofluids Demonstration Materials List

ferrofluid (follow instructions in the Procedure section of the Magnetic Fluids activity)

clear test tube, beaker or flask of suitable size, such as a 250 ml beaker

rare-earth magnet

paper or wax paper

paper towel

Ferrofluids Demo Procedure

1. In advance, make the ferrofluid 2. Show students the liquid in the clear container.

2. Ask students: "If I pour out this liquid, will it spill?" Wait to hear student responses, and then proceed.

3. Place the magnet under a piece of paper or wax paper.

4. Pour a small amount of ferrofluid onto the magnet and show the class.

5. Ask students: "How is this possible?" Wait to hear student responses, and then continue.

6. Move the liquid around while showing it to students.

7. Tilt the paper with the magnet and fluid still in contact, remove the magnet and watch the fluid drip into the container.

Ferrofluids Discussion

How was I able to magnetize the fluid? (Give students the opportunity to consider the fluid constituents.)

How big are these magnetic nanoparticles? (Give students a chance to participate and suggest how large these particles might be, using what they learned in the related lesson and activity on nano scale.)

How might I utilize this technology? (Give students the opportunity to contribute their ideas and think outside the box.)

Quantum Dots Demonstration Materials List

Quantum Dots Demo Procedure

1. Hold up the quantum dots solutions and ask students: "Describe what is special about these solutions." Wait to hear student responses, and then proceed.

2. Show students the liquid and have them look for any floating solid particles and remind them that "each vial is essentially a semiconductor with exceptional optical and electrical properties."

3. Turn off the classroom lights and ask students: "Is anything different about each solution?"

4. Wait to hear student responses, and then continue. NOTE: Depending on the room lighting, you may need to turn on a black light to really illustrate the fluorescence.

5. Turn on the classroom light.

Quantum Dots Discussion

"How did this solution emit different colors?" (Give students the opportunity participate and think about how this seemingly clear liquid was able to give off visible light.)

Tell students: "This liquid is comprised of many nanoparticle semiconductors and the incoming light interactions with the semiconductors cause the color emission." NOTE: At this point, DO NOT give away the associated activity by discussing size and fluorescence dependence.

Gold Nanoparticles Demonstration Materials List

20 ml gold colloid (see the Procedure section of the Thirsty for Gold activity for fabrication instructions) in 1-dram glass vial with top

disposable plastic pipet filled with pickle juice

waste container

vial or test tube holder

Gold Nanoparticles Procedure

1. Hold up the gold nanoparticle solution and ask students: "Describe what is special about these solutions?" Wait to hear student responses, and then proceed.

2. Tell students: "The solution contains gold nanoparticles." Ask them: "Do you know why my gold is red?" Then ask: "How much do you think my gold solution is worth?" Listen to student responses. Tell the students: "The solution's gold quantity is worth a fraction of a cent." and "The light is interacting differently with gold nanoparticles then it does with bulk gold."

3. Add one drop of pickle juice. Ask students "Do you see a color change?"

4. Continue to add drops until the solution changes from red to clear-blue.

Gold Nanoparticles Discussion

"How did this solution change colors?" (Give students the opportunity participate and think about how this seemingly clear liquid was able to change colors as electrolytes were added.)

Tell students: "The liquid is comprised of many gold nanoparticles (10-15nm diameter in size). Electrons surround each gold nanoparticle, creating a net negative surface charge. Adding electrolytes causes cations to bond to gold nanoparticles causing gold nanoparticle agglomeration. " NOTE: At this point, DO NOT give away the particle size effect on color change!

Lesson Background and Concepts for Teachers

Nanotechnology has existed in our society for centuries, yet only recently have we been able to see, control and produce such small materials for specific consumer, medical and engineering applications. The incredible phenomena unique to the small length scale are being exploited to create technologies that make the engineering and technology of nanoscience so exciting.

The three associated activities enable students to further explore ferrofluids, quantum dots and gold nanoparticles. Embedded within each activity is comprehensive background touching on fundamental topics related to chemistry and physics. Students also practice using scientific method and becoming exceptional observers. The activity questions provided on worksheets are designed to test students' understanding of the topic and critical thinking skills.
Ferrofluids
As a material scientist, the small scale characteristics become important when developing magnetic fluids. The challenge is to make a fluid magnetic without exceeding its Curie point. Scientists have developed paramagnetic salt solutions for magnetic fluids that exhibit less-than-adequate magnetic permeability, which would be expected, considering paramagnetic materials have a magnetic permeability far less than a ferromagnetic material. This is the point at which nanomaterials become increasingly important.

To meet such a challenge, scientists have developed ferromagnetic nanoparticles that are approximately 10 nm in diameter, but small enough to be suspended in various carrier fluids. Such suspension could be considered colloidal. Additionally, the size of each nanoparticle is a few atoms in diameter, which creates a single magnetic domain particle. That means that each nanoparticle is its own permanent magnet suspended in the carrier fluid. With a suitable surfactant to prevent particle agglomeration, the suspension can be manipulated under a controlled moderate magnetic field.

These magnetic fluids have received considerable attention over the last few decades, with applications geared towards rotary shaft sealing and audible speaker cooling systems. However, recent interest is in the application of ferrofluids to cancer treatments and drug delivery systems. Cancer treatment has been proposed through methods utilizing the heating effect of alternating magnetic fields and the energy lost from such cycling. For drug delivery systems, magnetic drugs with a suitable surfactant can be injected into the blood stream and manipulated with external magnetic fields to localize treatment to a particular human system. In the case of medical treatments, these advancements are only limited by the ability to create non-toxic, biologically compatible, magnetic particles.
Quantum Dots
Quantum dots offer a highly efficient process that mimics that of a bulk semiconductor but is quantized because of the length scales involved. "Quantum confinement" allows for quantum dots to be tailored to specific incident energy levels based on particle size. Additionally, nanoparticles offer superior surface area increases that also enhance absorption properties per unit volume and/or conductive properties. Material scientists have found that by varying quantum dot size energy, band gap size may increase or decrease. Larger-size quantum dots create a decrease in energy band gap and emit large wavelength photons (red-shift). Small quantum dot sizes generate an increase in energy band gap and emit short wavelength light (blue shift). This effect is demonstrated by quantum dot solutions of different particle sizes emitting different colors when exposed to UV light sources. Surface area affects enhance the efficiency of energy transfer properties, hence, quantum dots are known to have "high quantum yield." This also pertains to quantum dots emitting light long after exposure to a UV energy source.

Because of the unique quantum confinement effect, quantum dots may be used for a variety of applications, most notably for medical and energy applications. Tumor or cancer detection is a primary application for quantum dots. Scientists attach different antibodies to specific proteins and release them. Once quantum dots have permeated cell walls, they can tag their locations through fluorescence imaging. Additionally, because of the high quantum yield and sustaining light emittance, quantum dots remain fluorescent over time for imaging purposes. Solar energy is another targeted application for use of such dots. Specifically, quantum dots are of interest for their exceptional and tailored light optical properties. Additionally, a robust solar cell may be easily manufactured consisting of optical layers of differing quantum dot sizes to absorb specific incident photons. This allows solar cells to utilize all wavelengths of light provided by the Sun and boost solar cell efficiencies.
Gold Nanoparticles
In ancient times, gold and silver nanoparticles were used for staining glass with intense colors. In fact, it is recorded that ancient Romans used gold colloid for this very purpose. This is one example in which nanoscience and technology have been around hundreds of years, but only recently are we able to see and control this technology at its length scale.

In its bulk form, gold is a very intense yellow appearance. Similarly, silver is a very reflective or white color. A simple explanation is a phenomenon called surface plasmon resonance (SPR). Because metallic bonding does not require the sharing of valence electrons and that sub-shell energy levels be filled, free electrons become present in the atomic structure. These free electrons are present in cloud form and create a barrier to specific electromagnetic radiation (light) energy. Any light that is not absorbed is reflected. Because bulk gold absorbs infrared light, all visible light is reflected and elucidates the shiny-yellow appearance. However, at the nanometer scale, gold interacts differently with light where most visible wavelengths are absorbed while only a narrow portion of the light spectra is reflected. In fact, depending upon the specific size and shape of gold nanoparticles, they can appear red, purple, blue or other colors.

These unique optical characteristics lend gold nanoparticles to a variety of biosensing applications. Most notably are home pregnancy detection devices, DNA testing, and electrolyte detecting (as in this lesson and associated activity). However, these applications require knowledge of SPR, particle size, shape, ionic interactions between particles, and biochemistry.

Associated Activities

Magnetic Fluids - Students are introduced to a unique type of fluid-ferrofluids-whose shape can be influenced by magnetic fields! They make magnetic ink out of ferrofluids and test their creations. As they observe fluid properties as a standalone-fluid and under an imposed magnetic field, they come to understand the components of ferrofluids and their functionality.

Nanoparticles & Light Energy Experiment: Quantum Dots and Colors - Through their examination of different quantum dot solutions, students are introduced to the physical concept of the colors of the rainbow as light energy in the form of waves with distinct wavelengths. They make observations and measurements of these colorful liquids, and graph their data. They come to understand how nanoparticles interact with absorbing photons to produce colors. They learn the dependence of particle size and color wavelength and learn about practical applications for quantum dots.

Thirsty for Gold - Student teams conduct an experiment that uses gold nanoparticles as sensors of chemical agents to determine which of four sports drinks has the most electrolytes. In this way, students are introduced to gold nanoparticles and their influence on particle or cluster size and fluorescence. They also learn about surface plasmon resonance phenomena and how it applies to gold nanoparticle technologies, which touches on the basics of the electromagnetic radiation spectrum, electrolyte chemistry and nanoscience. Students develop a conceptual understanding of how gold nanoparticles function and learn some practical applications in biosensing.

Vocabulary/Definitions

band gap: Energy gap between conductive and valence bands. The size is characteristic of the material. For conductive materials, the band gap is nonexistent and both conductive and valence bands overlap. In semiconductor materials, both valence and conductive bands are separated. The band gap is the energy required to excite and electron into the conductive band.

colloidal: A chemical system in which a continuous liquid phase exists with a solid phase suspended in the liquid.

conductive band: The semiconductor energy band where electrons are transferred when excited from the valence band.

Curie point: The temperature at which ferromagnetism is lost due to excessive thermal agitation.

domain: A region where unpaired electrons are aligned parallel, creating a magnetic field.

electromagnetic radiation: Means of energy travel through a vacuum. Have characteristic wavelengths and frequencies.

electron cloud: The region of negative charge surrounding an atomic nucleus that is associated with an atomic orbital.

ferrofluid: Ferromagnetic particles suspended in a carrier fluid with the aid of a surfactant.

ferromagnetic: Long-range ordering phenomenon at the atomic level that causes unpaired electron spins to line up parallel with each other in a domain.

fluorescence : The emission of light by a substance that absorbs light by electromagnetic radiation of a different wavelength.

holes: Positive-charged space that is created when an electron is excited and moving. Holes can move free about the crystal. Typically, they are separated and form in p-type semiconductors.

plasmon: Oscillations of electron cloud against the fixed positive ions in a metal.

quantum confinement: An effect created by decreasing particles to the same magnitude as the particle wave function. Cause for change in electrical and optical properties.

quantum dots: Semiconducting nanoparticles that are able to confine electrons in small, discrete spaces.

quantum yield: The number of times an event occurs per photon absorbed by the system.

resonance: The selective response of an object or system that vibrates in step with an externally applied vibration.

surface plasmon resonance: The excitation of surface plasmons by light for planar or nanoparticle surfaces.

surface tension: An increased attraction of molecules at the surface of a liquid resulting from forces of attraction on fewer sides of the molecules.

surfactant: A chemical that acts as a wetting agent to lower the surface tension of a liquid and improve spreadability.

valence band: A semiconductor energy band where holes are transferred when electrons are excited and transferred to the conductive band.

Assessment

Embedded Lesson Assessment

Demo Discussions: After each demonstration, ask students questions about what they just observed to elicit their understanding and draw out any questions, as described in the Introduction/Motivation section.

Post-Introduction Assessment

Vocabulary Dive: After the lesson, but before conducting the associated three activities, divide the class into teams of two students each. Give each pair one vocabulary word and its definition. Have each team spend 5-10 minutes researching the term on the Internet so they are prepared to share the word and definition with the class, with enough background information to explain it more fully if the definition is not enough for other students to understand. As students share their terms and definitions, make connections among the various vocabulary words.

Lesson Summary Assessment

Team Poster Project: After students have completed the two lessons and four activities of the unit, assign student pairs to each create posters that summarize what was learned during the unit. This summary assessment is fully described in the NanoTech: Insights into a Nano-Sized World unit document, and includes a grading rubric for the teacher.

References

Benson, Harris. University Physics - Revised Edition. New York, NY: John Wiley & Sons, Inc., 1995, pp. 662-667.

Greenberg, Andrews. Gold Nanoparticles as Sensors for Electrolytes in Sports Drinks. Nanoscale Science and Engineering Center, University of Wisconsin-Madison. NSF Grant No. DMR0425880. Accessed September 27, 2012. http://mrsec.wisc.edu/Edetc/EExpo/sensors/NanogoldSensors_ProgramGuide.pdf

Lindsay, Stuart .M. Introduction to Nanoscience. New York, NY: Oxford University Press, Inc., 2010, pp. 318-335.

Odenbach, Stefan. Ferrofluids: magnetically controllable liquids. Published March 18, 2002. Proceedings in Applied Mathematics and Mechanics. Vol. 1, Issue 1, pp. 28-32. Accessed September 27, 2012. http://onlinelibrary.wiley.com/doi/10.1002/1617-7061(200203)1:1%3C28::AID-PAMM28%3E3.0.CO;2-8/abstract

Ruuge, E.K. and A.N. Rusetski, Magnetic fluids as drug carriers: Targeted transport of drugs by a magnetic field. Published 1993. Journal of Magnetism and Magnetic Materials. Vol. 122, Issue 1-3, pp. 335-339. Accessed September 27, 2012. http://adsabs.harvard.edu/abs/1993JMMM..122..335R

Sanderson, Katharine. "Quantum dots go large: A small industry could be on the verge of a boom," Special Report, Nature. Macmillan Publishers Ltd. Vol. 459, No. 11, pp. 760-761; June 2009. Accessed September 20, 2012. http://unanotech.com/wp-content/uploads/2011/06/Nature_Quantum_dots_go_large.pdf

Williams, Linda and Wade Adams. Nanotechnology Demystified. New York, NY: McGraw-Hill, 2007, pp. 146-149.

Winter, Jessica. Gold Nanoparticle Biosensors. Revision 3 published May 23, 2007. Center for Affordable Nanoengineering of Polymeric Biomedical Devices, The Ohio State University (a National Science Foundation Nanoscale Science and Engineering Center [NSEC]). Accessed September 27, 2012. http://www.nsec.ohio-state.edu/teacher_workshop/Gold_Nanoparticles.pdf

Copyright © 2013 by Regents of the University of Colorado; original © 2011 University of Houston

Contributors Marc Bird; Sarah Castillo

Supporting Program National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs, University of Houston

Acknowledgements

This curriculum was created by the University of Houston's College of Engineering with the support of National Science Foundation GK-12 grant no. 0840889. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: January 12, 2019

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Through three teacher-led demonstrations, students are shown samplers of real-world nanotechnology applications involving ferrofluids, quantum dots and gold nanoparticles. This nanomaterials engineering lesson introduces practical applications for nanotechnology and some scientific principles related to such applications. It provides students with a first-hand understanding of how nanotechnology and nanomaterials really work.

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Experiment on Natural Nanomaterials

We have many natural nanomaterials around us and in this experiment you will learn that two very common materials, milk and gelatine, are indeed two of these. The properties of these materials are directly connected to their molecular supra-organisation, which includes nanotechnologies.

If you want to know more about the properties of milk and gelatine do the experiment that NANOYOU proposes you. You will find the information you need in the documents below.
Please note that the experiments described in the following training kit use chemicals which need to be used according to MSDS specifications and specific school safety rules. Personal protection must be taken as indicated. As with all chemicals, use precautions. Solids should not be inhaled and contact with skin, eyes, or clothing should be avoided. Wash hands thoroughly after handling. Dispose as indicated. All experiments must be conducted in the presence of an educator trained for science teaching. All experiments will be carried out at your own risk. Aarhus University (iNANO) and the entire NANOYOU consortium assume no liability for damage or consequential losses sustained as a result of the carrying out of the experiments described.
Experiment on Natural Nanomaterials by NANOYOU is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. However, this does not apply to some images used in this kit which are protected by copyright. Click here to view a list of these images. Permissions beyond the scope of this license may be available contacting This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

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We have many natural nanomaterials around us and in this experiment you will learn that two very common materials, milk and gelatine, are indeed two of these. The properties of these materials are directly connected to their molecular supra-organisation, which includes nanotechnologies.

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A World of New Possibilities

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A Matter of Taste: The Science Behind Better-Tasting Stuff

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A Matter of Taste: The Science Behind Better-Tasting Stuff

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If you have a certain kind of diabetes you already know this-getting a tiny bit of blood and then testing it for glucose is a daily ritual. People with diabetes have to test their blood a lot because if their blood sugar goes out of whack it can cause serious trouble and make them very sick.

New instruments to test blood glucose and make it less painful have been developed using some things from nanotechnology. Nanotechnology has also been used to build tiny pumps that deliver insulin, the molecule your body uses to control blood glucose. But wouldn't it be neat if you didn't have to prick yourself? What if there was some kind of gizmo that would automatically tell you what your blood glucose level was?

How about something cool like a...tattoo?

Scientists have been working on tattoos that instead of using ordinary ink use nanoparticles that can sense the level of glucose in your blood. These nanoparticles are made of a special polymer that is biocompatible and contains a molecule that fluoresces in the presence of glucose. Shine a light on the nano tattoo and it tells you how much glucose is in your blood.The tattoos are fluorescent so you can only see them under the special light. And that's probably okay, since you don't want to broadcast to your friends (and strangers) what's going on with your body. There are still lots of things to be worked out, but the idea is neat and there are a lot of different kinds of tests that could be done with this sort of nanotechnology.

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If you have a certain kind of diabetes you already know this-getting a tiny bit of blood and then testing it for glucose is a daily ritual. People with diabetes have to test their blood a lot because if their blood sugar goes out of whack it can cause serious trouble and make them very sick.

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The bonds that hold atoms together to form molecules are called covalent bonds. They are pretty tough and not easily made or broken apart. It takes energy to make the bonds and energy is released when the bonds are broken.

Trees take light and use it to make bonds between carbon atoms and molecules of cellulose. If we burn wood, those bonds are broken and we get heat and some light. But there is more to bonds between atoms than just energy-they are also what gives a molecule its shape.

Cellulose looks like long strings if you look at it with an electron microscope. These long strings of cellulose form bundles because of another kind of bonding called hydrogen bonding. The shape of cellulose molecules makes it easy for hydrogen bonds to form between strings. While not as strong as covalent bonds, hydrogen bonds are still pretty strong, so it is the shape of cellulose that makes wood a strong material.

NANOTECHNOLOGY AND MOLECULES

Nanotechnology can be used to make molecules. Atoms floating around in air or in liquid can sometimes bond to form molecules, but it isn't that easy because of the rules about what can bond and what can't.

Imagine taking Lego blocks and instead of fitting them together with your hands you stood across the room from your friend and threw them at each other to try to connect them. Every once in awhile they might stick together, but it could take a million attempts to get it to work once. If you have billions and billions of molecules, well, maybe it would work. So how many atoms are there, let's say, in a bunch of air? Lots and lots, around 2.69 x 10 ¹⁹ molecules in every cubic centimeter. That's 2,690,000,000,000,000,000,000 molecules.

THE FUTURE OF NANOTECHNOLOGY

But will we someday be able to make molecules like we build things out of Legos? Back about 30 years ago, a guy by the name of Eric Drexler proposed something like that, molecular machines that could make molecules. These machines are imagined to be able to take elements and stick them together to make molecules and bigger things the same way we make a car or a toaster. We are still a long way away from that kind of stuff and there is a lot of controversy-if it is even possible-only time will tell!

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The bonds that hold atoms together to form molecules are called covalent bonds. They are pretty tough and not easily made or broken apart. It takes energy to make the bonds and energy is released when the bonds are broken. Trees take light and use it to make bonds between carbon atoms and molecules of cellulose.

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Exploring the worldof science and nanotechnology...

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Exploring the worldof science and nanotechnology...

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Nanooze! | Nanoscale Science & Technology

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What is a (we say it.... nah-news)? Nanooze is not a thing, Nanooze is a place. A place to hear about the latest exciting stuff in science and technology, particularly things related to Nanotechnology, the science of really small things !.

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was created for kids

Nanooze (we say nah-news) is NNIN's branded "direct to student" outreach activity. It consists of a kid-friendly web site, a print edition distributed through classrooms, workshops, and museums, and two museum quality interactive exhibits. Nanooze is a place for kids to learn about the latest exciting stuff in science and technology. What kind of stuff? Discoveries about the world that is too small to see and making tiny things. Nanooze makes reading and learning abou these discoveries fun!

Please note that nanotechnology is very broad and that many nanotechnology concepts are accessible to kids when presented properly. And many nanotechnology concepts are just variations on things that are already in the curriculum.

Nanooze is distributed by NNIN and produced by Cornell University, more specifically, by Prof. Carl Batt of Cornell University. Questions and comments on content should be directed to Professor Batt ( cab10@cornell.edu).

Nanooze started as a cool website, directed at kids. Nanooze on the web is available in Engish, Spanish, and Portuguese.

Nanooze in Print is a free classroom "magazine" devoted to nanotechnology. Each issue is full of articles and attractive color pictures on exciting topics in science and technology, delivered at the "kid level". While the content is generally aimed at the middle school level, it is written to be accessible and enjoyable for almost all ages. The reading level is appropriate for upper elementary students. Nanooze is mostly used as classroom enrichment or resource material. It can be used in support of specific curriculum, for topical "research", and as free reading material. Two or three issues per year are published; about 100,000 of each issue have been distributed.

Nanooze in Print is distributed in classroom packs of 30 (or multiples thereof), free of charge to teachers for classroom use. It is also distributed in bulk to science museums and other research centers who act as secondary distributors. Currently 13 issues have been published. Content of each issue can be viewed below or at http://nanooze.org/articles/downloads/

All back issues are available except issue 1. Subscriptions for future issues as well as requests for back issues should be directed to Prof. Carl Batt at Cornell, cab10@cornell.edu, or to Dr. Lynn Rathbun, NNIN Deputy Director, LCR2@cornell.edu. Sorry, we can only ship to school or museum/research center addresses. And sorry, we can not distribute individual copies. Everyone, however, is welcome to view and print the content online. When requesting issues, please indicate:

Your Name

School name and address including zip code

Grades taught if applicable

Which issues you would like

Number of copies of each requested

NNIN is happy to consider large scale (district wide) distribution arrangements. We are particularly interested in novel uses of Nanooze and any information of the effectiveness of Nanooze in various situations.

NNIN is happy to consider non-profit partners (museums, research centers, university outreach programs) for secondary distribution of Nanooze in Print. Please contact Prof. Batt or Dr. Rathbun.

Nanooze in Print--in Spanish

Through the efforts of Dr. Yajaira Sierra-Sastre and some enthusiastic students in Puerto Rico, NNIN is now able to offer print-ready files of Nanooze in Print, in Spanish. Currently, Issue 6 , 8, 9, 10, and 11 are available.. NNIN is not at this point able to distribute printed copies of Nanooze in Spanish, but feel free to print the files for your use. Your feedback is appreciated.

Nanooze the Exhibit

NNIN has two 1500 sq.ft. interactive "museum" displays that are currently deployed at Disney World Epcot and at Innoventions in Disneyland Anaheim. There exhibits were developed under other progr ams, but now fall under the "Nanooze" brand. They promote nanotechnology and Nanooze to hundreds of thousands of visitors each year.

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Nanooze (we say nah-news) is NNIN's branded "direct to student" outreach activity. It consists of a kid-friendly web site, a print edition distributed through classrooms, workshops, and museums, and two museum quality interactive exhibits. Nanooze is a place for kids to learn about the latest exciting stuff in science and technology.

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Serving Nanoscale Science, Engineering & Technology

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Welcome students !

This is the place to learn about the exciting field of nanotechnology.

This site has lots of intersting information on nanotechnology, to help you with school work or to just to your curiosity.

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This is the place to learn about the exciting field of nanotechnology. This site has lots of intersting information on nanotechnology, to help you with school work or to just to your curiosity.

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Hey kids. Interested in nanotechnology? Want a nanotechnology science project?

There are lots of easy nanotechnology science projects. You can make yourself look even smarter than you are! They will say, "Wow! You must be really smart doing nanotechnology".

Anyway, kidding aside, this is the place to look for ideas. There are many lessons in out Nanotechnology Curriculum Materials that could be turned into science projects. Check them out.

For example

Make a Rube Goldberg machine using a shape memory alloy as an actuation element.

Make a model of a nanotube and a buckyball

Do some electroplating

There are many products that contain nanotechnology so you may not even have to buy anything special.

Check out the effectiveness of different kinds of sunscreen, including those containing nanoparticles

So nanosocks really keep your feet from smelling. How and why?

Do bandages impregnated with nanosilver really kill germs?

Are sports products with nanomaterials actually perform better?

Do pants with nanocoating actually shed water and stains better?

Use DVDs and CDs as diffraction gratings.

Hey! If you do a cool nanotechnology science project, send us a note and picture at rathbun@cnf.cornell.edu. If you give us permission, we will post it here.

Good luck!

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Hey kids. Interested in nanotechnology? Want a nanotechnology science project? There are lots of easy nanotechnology science projects. You can make yourself look even smarter than you are! They will say, "Wow! You must be really smart doing nanotechnology". Anyway, kidding aside, this is the place to look for ideas.

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In the face of the coronavirus pandemic, it is time for the nanotechnology community to shine and build on its experience with nanoscale materials and drug delivery to provide knowledge and tools for COVID-19 vaccine and therapeutics development.

While many parts of the world remain in lockdown and universities are closed, numerous nanotechnology research labs have kept open throughout the last months to redirect their efforts towards the development of a vaccine and/or nanoformulations of therapeutics for the treatment of COVID-19. Expertise in nucleic acid and drug delivery, cancer nanovaccines, immunoengineering, nanotechnology-based sensors and platform technologies positions nanotechnology in a unique place to tackle some of the key issues in pre-clinical and clinical COVID-19 research. After all, viruses are naturally occurring nanoparticles, and indeed, the nanotechnology community has long been trying to capitalize on the properties of viruses and mimic their behaviour, for example, for the design of virus-like nanoparticles for targeted drug delivery and gene editing.

In this Focus issue, nanotechnologists from different areas discuss ongoing efforts in COVID-19 vaccine development, the potential advantages of nanoformulations for the most promising therapeutic candidates, nanotechnological tools that may facilitate worldwide vaccine manufacturing and distribution, and nanomaterial-based viral disinfectants and detection platforms.

Vaccines are the most promising solution to mitigate the spread of the coronavirus SARS-CoV-2. Nanomaterials play an important role in all aspects of vaccine design, delivery and administration. Nanoparticles enable multivalent antigen presentation and stabilization of antigens upon administration, they can serve as adjuvants to boost the immune response, and they can act as carriers for the targeted delivery of antigens. Indeed, an mRNA vaccine delivered by a liposomal nanoparticle is amongst the candidates currently in clinical trials against SARS-CoV-2. While it remains a fact that no mRNA or DNA vaccine is currently approved for any disease, the delivery of nucleic acids requires some form of modification or a nanodevice to prevent degradation in the body, and liposomal devices have indeed already been approved for RNA delivery, albeit not yet for vaccines. The nanotechnology community has further gained immense knowledge over the past years in the development of cancer nanovaccines to boost and/or reprogram host immunity, which may now provide a solid starting point for immune-mediated approaches against SARS-CoV-2.

Importantly, nanomaterial-based platform technologies may also play a key role in the distribution and administration of vaccines in resource-poor or densely populated developing countries by enabling self-administration, for example, through microneedle patches, single-dose slow-release implants, film-based vaccines, or by using plant viral nanoparticles for antigen delivery, which do not require cold chains. In a global pandemic, in which healthcare systems are operating at the limit, such self-administration technologies may prove extremely valuable. Cold chain requirements can also be circumvented by applying alternative production platforms, such as molecular farming in plants. Thereby, vaccines are produced in edible leaf tissue for the vaccination of humans and livestock.

From a therapeutic standpoint, the repurposing of existing drugs is currently at the centre of research owing to a lack of new therapeutic treatments against COVID-19. So far, only a few drugs have demonstrated efficacy against COVID-19 in clinical trials. The anti-inflammatory corticosteroid dexamethasone has recently been shown to have life-saving efficacy in a clinical trial. Dexamethasone has previously been formulated as a nanomedicine for the treatment of other diseases; for example, liposomal dexamethasone has shown efficacy in multiple myeloma. In the case of COVID-19, a nanomedicine formulation may enable the targeting of alveolar macrophages upon pulmonary delivery or of phagocytes at inflammation sites following intravenous administration. Moreover, the anti-fibrotic effects of dexamethasone can be potentiated by reformulating it as a nanomedicine. The argument can be made, of course, that a nanoformulation will make the therapy even more expensive (not even speaking of the need for additional clinical trials); however, if such nanoformulation improves clinical outcomes, and thus, would allow critically ill patients to leave the intensive care unit earlier, the cost reduction in hospitalization and faster patient recovery may be well worth it.

A main reason for the ongoing repurposing of drugs and fast-tracking of preclinical and clinical testing of vaccine formulations for COVID-19, is the lack of time. The development, clinical testing and approval of new drugs usually take years. Therefore, in the future, it will be important to scientifically and financially invest in platform technologies that can then be rapidly repurposed on demand, to be better prepared for future outbreaks - a lesson (hopefully) learned from the current pandemic. Nanodevices and nanoformulations offer such platform technologies, and a thorough investigation of their fundamental science and biological interactions will be of great value for the future development of vaccines and therapeutics.

Facing the SARS-CoV-2 pandemic, the nanotechnology community has joined forces and provides their tools and experience to the COVID-19 research efforts. There has been criticism about the clinical impact of nanotechnology, but the time has now come to highlight the knowledge and previous experience of nanotechnologists in vaccine and drug development, delivery and distribution. The ongoing research efforts and collaborations with the clinic and industry will hopefully have an impact on the future of our field to further open the way for the clinical translation of nanotechnology. However, while lockdowns are starting to be eased, let us not forget that a vaccine may still be far away from clinical reality and that the road from preclinical testing to clinical efficacy can be long and bumpy - a fact that the nanotechnology community is well aware of.

About this article

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In the face of the coronavirus pandemic, it is time for the nanotechnology community to shine and build on its experience with nanoscale materials and drug delivery to provide knowledge and tools for COVID-19 vaccine and therapeutics development.

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Nanotechnology has become a popular buzzword in science and politics. This key technology is considered not only a major source of innovation in technology, medicine and other fields, but also one of the main challenges for the 21st century. European universities and high-level vocational training programmes already cover this technology extensively. However, although the word nanotechnology will be familiar to many high-school students, the subject is not widely taught in European schools. This article outlines several initiatives to increase awareness of nanotechnology among European science teachers, and details two nanotechnology experiments for the classroom.

What is nanotechnology?

Medieval stained glass
window using nanotechnology
Image courtesy of NanoBioNet eV

Nanotechnology is not really anything new. It deals with entities and processes on the scale of 10⁻⁹ m (1 nanometre), which is the dimension of molecules and atoms - a scale that chemists, biochemists and cell biologists have worked with for centuries.

At the nanoscale, the properties of a material may change. For example, hardness, electrical conductivity, colour or chemical reactivity of minuscule particles of materials are related to the diameter of the particle. Specific functionalities, therefore, can be achieved by reducing the size of the particles to 1-100 nm.

A well-known application of early nanotechnology is the ruby red colour that was used for stained glass windows during the Middle Ages (see image). The colour is a result of gold atoms clustering to form nanoparticles instead of the more usual solid form. These small gold particles allow the long-wave red light to pass through but block the shorter wavelengths of blue and yellow light. The colour, therefore, depends both on the element involved (gold) and on the particle size; silver nanoparticles, for example, can give a yellow colour.

What is new, though, is the multidisciplinary approach and the ability to 'look' at these entities. The atomic force microscope, which was developed in the late 1980s, allows scientists to view structures at a nano-metric scale and to handle even single atoms via scanning probe microscopy. Now biologists can discuss steric effects of cell membranes with chemists, while physicists provide the tools to watch the interaction in vivo. Nanoparticles play an important role in the pharmaceutical industry (delivering active agents to the required part of the body) in the production of emulsion paint and cosmetics and in the optimisation of catalysts. Nanotechnology, therefore, has combined all natural sciences and creates cross-links between the different disciplines.

Initiatives for schools

Students at the Saarlab laboratory
Image courtesy of Lehrstuhl für
physikalische Chemie, Universität
des Saarlandes

Some materials are already available to support science teachers in introducing their students to nanotechnology, although the materials tend only to be published in the national language. For example, the German Saarlab Initiative offers lab days for whole school classes, while some European science museums and science centres have exhibitions about nanotechnology or, like the German Nanotruck, bring people closer to the subject using touring exhibitions that can be booked for public events. Some universities, like the University of Cambridge, offer visits to schools, interactive lectures, seminars and workshops. Additionally, there are many online resources that provide information, films and games for schools and students.

To fill this gap, the NanoBioNet eV not only provides vocational courses and training for teachers, but has developed a multilingual (German, English and French) experimental kit (the NanoSchoolBox) to teach school students about nanotechnology. Some of the experiments in the NanoSchoolBox are suitable for demonstration experiments; others can be integrated without too much preparation into hands-on lessons under the guidance of the teacher.

The experimental school kit includes 14 experiments and five exhibits which deal with the following topics:

The lotus effect and technical applications of nanolayers

Functionality through nanotechnology (showing different effects of nanotechnological coatings, such as scratch resistance, fire protection and the increase in electrical conductivity through indium tin oxide)

Use of titanium dioxide in nanotechnology

Ferrofluids

Nano-scaled gold clusters

Although the experiments are intended principally for chemistry lessons, the interdisciplinary structure of nanotechnology means that some of them are also suitable for physics or biology classes. Below are two examples.

Ferrofluids

Diagram showing the composition
of ferrofluid particles
Image courtesy of NanoBioNet eV

Magnetic field lines
Image courtesy of NanoBioNet eV

Ferrofluids are colloidal dispersals of extremely small ferromagnetic particles (i.e. particles that can be permanently magnetised by an external magnetic field), such as cobalt, nickel or iron, suspended in a hydrocarbon liquid. The particles are coated with a surfactant to prevent them from clumping together. Ferrofluids are the only magnetic materials in liquid form.

The NanoSchoolBox includes both ferrofluids for performing the experiment and instructions for making your own ferrofluids in the laboratory. Ferrofluids may also be bought from FerroTec GmbH.

In this simple experiment, the ferromagnetic particles align themselves with the magnetic field lines around a magnet, thus making the magnetic field visible.

Materials

Ferrofluid

Empty crimp-top glass tube

Tenside solution (surfactant)

Magnet

Pipette

Water

Procedure

1. Fill the tube three-quarters full of water and add 2-5 drops of tenside solution (surfactant).

2. Carefully use the pipette to add a few drops of ferrofluid, which will settle at the bottom.

3. Close the tube tightly.

4. Bring the magnet close to the ferrofluid.

As the particles try to align themselves with the magnetic field, a typical 'porcupine' is formed, the prickles representing the magnetic field lines (see images). Surface tension of the fluids and gravity counteract the magnetic field with the result that ordered structures are created in the liquid as a reaction to the three forces.

1. Trying moving the ferrofluid through the water with the aid of the magnet. Depending on whether the magnet is held parallel or vertically to the surface of the ferrofluid, the orientation of the magnetic field changes and, consequently, the orientation of the fluid changes.

2. Shake the tube gently to disperse the ferrofluid in the water. As the ferroparticles do not dissolve, they eventually settle at the bottom. You can accelerate this process with the aid of a magnet, observing beautiful effects. To achieve this, draw the magnet past the side of the tube quickly and away again. In this way, you accelerate the ferrofluids and produce streaks, clouds, and so forth.

Safety notes

Nanoscale gold

Research scientists use the light-absorbing property of gold particles to detect biomolecules. For example, antibodies can be tagged by coupling them with gold particles. When a white light is shone on them, the red colour of the metal particles is visible. This is applied in some cases in home pregnancy tests, in which gold nanoparticles are finely distributed on the test strip.

The UltiMed® pregnancy test, for example, relies on this principle to detect human chorionic gonadotropin (hCG), a hormone released early in pregnancy by the fertilised egg and the lining of the uterus. hCG consists of two subunits: α and ?. On the test strip, α-subunits of hCG are immobilised, forming a line that will turn red to indicate a pregnancy. Elsewhere in the strip, colloidal gold particles are tagged with monoclonal antibodies specific to the ?-subunit of hCG.

Pregnancy test strip
Image courtesy of kimkole / iStockphoto

When the strip is dipped in urine, the liquid allows the tagged gold particles to move through the strip by capillary action. If the urine contains hCG (i.e. if the woman is pregnant), ?-subunits of hCG bind to the tagged gold particles. When the ?-subunits bound to the gold reach the immobilised α-subunits, the α- and ?-subunits bind together, forming a gold-hCG complex. If the concentration of hCG is high enough, the complex is visible as a red line, indicating that the woman is pregnant. Further gold particles bind to a second line, indicating that the test (whether positive or negative) was correctly performed.

In the following experiment, we will produce nanoscale gold clusters, which are easily detected by their typical ruby-red colour. One way of producing nanoscale gold, described here, is the citrate method. This involves producing either colloidal gold or gold clusters in a solution.

A cluster, or nanoparticle, is a collection of 3 to 50 000 atoms. The diameter of the gold nanoparticles is generally between 12-18 nm. If the clusters are spatially distributed in another physical medium, the entire system is known as a colloid.

Chemical equation for the production of gold clusters
Image courtesy of Nicola Graf

The experiment is based on a redox reaction of tetrachloraurate (also known as tetrachlorauric acid or tetrachlorauric (III) acid trihydrate), in which gold ions are reduced to atomic gold clusters. The reductant sodium citrate (also called trinatriumcitrate dihydrate) not only reduces the gold but also acts as a dispersion medium to stabilise the gold clusters that are created.

By adding the reductant, the atomic coagulation of the metal ions is halted and the result is a colloidal cluster enclosed by a ligand case.

Those colloids are detected by the Tyndall effect. This occurs when light is shone through a colloidal suspension: the light path can be seen in the liquid as visible light is scattered by suspended, microscopically small particles, the diameter of which is in the order of magnitude of the wavelength of visible light (400-800 nm). In contrast, when light is shone through a solution without colloids (e.g. ink), the light passes through without being scattered, so the light path is not visible.
Materials

Auric chloride solution, HAuCl₄ (0.1 g auric chloride in 20 ml H₂O)

Distilled water

Hotplate or immersion heater

Something for stirring (spoon, stirrer or similar), ideally a heatable magnetic stirrer

1 fireproof glass beaker (50-100 ml)

Thermometer (up to 100 °C)

Laser pointer (optional)

Safety note:

Auric chloride is caustic and harmful if swallowed.

Procedure

1. Add 0.5 ml (approx. 15 drops) auric chloride solution to 28 ml distilled water.

2. Heat the solution to 100 °C on the stirrer or hot plate.

3. Once the solution reaches 100 °C and starts to bubble, add 1.5 ml citrate solution as quickly as possible, stirring vigorously.

The initial red colour of the auric chloride solution intensifies until it becomes a deep red. At temperatures between 85 and 90 °C, it will take approximately 5 minutes until the colour changes; at 100 °C, the reaction is even faster.

Depending on the size of the particles formed, you may get a violet colour instead of red.

The gold colloids can be detected through the Tyndall effect. Use the laser pointer to shine light sideways through the solution. The light path can be observed as it passes through the solution.

Additional experiments

For comparison, repeat the experiment with 0.5 ml auric chloride solution and 50 ml distilled water. Compare the time needed for the colour change to occur.

If you increase the citrate concentration in a further experiment, the colloids will have a deep violet colour, a result of colloids of a different size forming.

Further information

For further information, please contact NanoBioNet eV: www.nanobionet.de
Email: info@nanobionet.de
Tel: +49 (0)681 685 7364

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Nanotechnology has become a popular buzzword in science and politics. This key technology is considered not only a major source of innovation in technology, medicine and other fields, but also one of the main challenges for the 21st century. European universities and high-level vocational training programmes already cover this technology extensively.

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Risk Assessment for using the ‘Time for Nano’ Nano-day activities

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Risk Assessment for using the ‘Time for Nano’ Nano-day activities

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This timeline features Premodern example of nanotechnology, as well as Modern Era discoveries and milestones in the field of nanotechnology.

Premodern Examples of Nanotechnologies
Early examples of nanostructured materials were based on craftsmen's empirical understanding and manipulation of materials. Use of high heat was one common step in their processes to produce these materials with novel properties.

The Lycurgus Cup at the British Museum, lit from the outside (left) and from the inside (right)

4th Century: The Lycurgus Cup (Rome) is an example of dichroic glass; colloidal gold and silver in the glass allow it to look opaque green when lit from outside but translucent red when light shines through the inside. (Images at left.)

Polychrome lustreware bowl, 9th C, Iraq, British Museum (© T rinitat Pradell 2008)

9th-17th Centuries: Glowing, glittering "luster" ceramic glazes used in the Islamic world, and later in Europe, contained silver or copper or other metallic nanoparticles. (Image at right.)

6th-15th Centuries: Vibrant stained glass windows in European cathedrals owed their rich colors to nanoparticles of gold chloride and other metal oxides and chlorides; gold nanoparticles also acted as photocatalytic air purifiers. (Image at left.)

13th-18th Centuries: "Damascus" saber blades contained carbon nanotubes and cementite nanowires-an ultrahigh-carbon steel formulation that gave them strength, resilience, the ability to hold a keen edge, and a visible moiré pattern in the steel that give the blades their name. (Images below.)

( Left) A Damascus saber (photo by Tina Fineberg for The New York Times). ( Right) High-resolution transmission electron microscopy image of carbon nanotubes in a genuine Damascus sabre after dissolution in hydrochloric acid, showing remnants of cementite nanowires encapsulated by carbon nanotubes (scale bar, 5 nm) (M. Reibold, P. Paufler, A. A. Levin, W. Kochmann, N. Pätzke & D. C. Meyer, Nature 444, 286, 2006).

Examples of Discoveries and Developments Enabling Nanotechnology in the Modern Era
These are based on increasingly sophisticated scientific understanding and instrumentation, as well as experimentation.

"Ruby" gold colloid ( Gold Bulletin 2007 40,4, p. 267)

1857: Michael Faraday discovered colloidal "ruby" gold, demonstrating that nanostructured gold under certain lighting conditions produces different-colored solutions.

1936: Erwin Müller, working at Siemens Research Laboratory, invented the field emission microscope, allowing near-atomic-resolution images of materials.

1947: John Bardeen, William Shockley, and Walter Brattain at Bell Labs discovered the semiconductor transistor and greatly expanded scientific knowledge of semiconductor interfaces, laying the foundation for electronic devices and the Information Age.

1950: Victor La Mer and Robert Dinegar developed the theory and a process for growing monodisperse colloidal materials. Controlled ability to fabricate colloids enables myriad industrial uses such as specialized papers, paints, and thin films, even dialysis treatments.

1951: Erwin Müller pioneered the field ion microscope, a means to image the arrangement of atoms at the surface of a sharp metal tip; he first imaged tungsten atoms.

1956: Arthur von Hippel at MIT introduced many concepts of-and coined the term- "molecular engineering" as applied to dielectrics, ferroelectrics, and piezoelectrics

1958: Jack Kilby of Texas Instruments originated the concept of, designed, and built the first integrated circuit, for which he received the Nobel Prize in 2000. (Image at left.)

1959: Richard Feynman of the California Institute of Technology gave what is considered to be the first lecture on technology and engineering at the atomic scale, "There's Plenty of Room at the Bottom" at an American Physical Society meeting at Caltech. (Image at right.)

1965: Intel co-founder Gordon Moore described in Electronics magazine several trends he foresaw in the field of electronics. One trend now known as " Moore's Law," described the density of transistors on an integrated chip (IC) doubling every 12 months (later amended to every 2 years). Moore also saw chip sizes and costs shrinking with their growing functionality-with a transformational effect on the ways people live and work. That the basic trend Moore envisioned has continued for 50 years is to a large extent due to the semiconductor industry's increasing reliance on nanotechnology as ICs and transistors have approached atomic dimensions. 1974: Tokyo Science University Professor Norio Taniguchi coined the term nanotechnology to describe precision machining of materials to within atomic-scale dimensional tolerances. (See graph at left.)

1981: Gerd Binnig and Heinrich Rohrer at IBM's Zurich lab invented the scanning tunneling microscope, allowing scientists to "see" (create direct spatial images of) individual atoms for the first time. Binnig and Rohrer won the Nobel Prize for this discovery in 1986.

1981: Russia's Alexei Ekimov discovered nanocrystalline, semiconducting quantum dots in a glass matrix and conducted pioneering studies of their electronic and optical properties.

, which is a molecule resembling a soccer ball in shape and composed entirely of carbon, as are graphite and diamond. The team was awarded the 1996 Nobel Prize in Chemistry for their roles in this discovery and that of the fullerene class of molecules more generally. (Artist's rendering at right.) 1985: Rice University researchers Harold Kroto, Sean O'Brien, Robert Curl, and Richard Smalley discovered the Buckminsterfullerene (C60), more commonly known as the buckyball

1985: Bell Labs's Louis Brus discovered colloidal semiconductor nanocrystals (quantum dots), for which he shared the 2008 Kavli Prize in Nanotechnology.

1986: Gerd Binnig, Calvin Quate, and Christoph Gerber invented the atomic force microscope, which has the capability to view, measure, and manipulate materials down to fractions of a nanometer in size, including measurement of various forces intrinsic to nanomaterials.

1989: Don Eigler and Erhard Schweizer at IBM's Almaden Research Center manipulated 35 individual xenon atoms to spell out the IBM logo. This demonstration of the ability to precisely manipulate atoms ushered in the applied use of nanotechnology. (Image at left.)

1990s: Early nanotechnology companies began to operate, e.g., Nanophase Technologies in 1989, Helix Energy Solutions Group in 1990, Zyvex in 1997, Nano-Tex in 1998....

1991: Sumio Iijima of NEC is credited with discovering the carbon nanotube (CNT), although there were early observations of tubular carbon structures by others as well. Iijima shared the Kavli Prize in Nanoscience in 2008 for this advance and other advances in the field. CNTs, like buckyballs, are entirely composed of carbon, but in a tubular shape. They exhibit extraordinary properties in terms of strength, electrical and thermal conductivity, among others. (Image below.)

Carbon nanotubes (courtesy, National Science Foundation). The properties of CNTs are being explored for applications in electronics, photonics, multifunctional fabrics, biology (e.g., as a scaffold to grow bone cells), and communications. See a 2009 Discovery Magazine article for other examples

SEM micrograph of purified nanotube "paper" in which the nanotubes are the fibers (scale bar, 0.001 mm) (courtesy, NASA).

An array of aligned carbon nanotubes, which can act like a radio antenna for detecting light at visible wave- lengths (scale bar 0.001 mm) (courtesy, K. Kempa, Boston College).

1992: C.T. Kresge and colleagues at Mobil Oil discovered the nanostructured catalytic materials MCM-41 and MCM-48, now used heavily in refining crude oil as well as for drug delivery, water treatment, and other varied applications.

MCM-41 is a "mesoporous molecular sieve" silica nanomaterial with a hexagonal or "honeycomb" arrangement of its straight cylindrical pores, as shown in this TEM image (courtesy of Thomas Pauly, Michigan State University).

This TEM image of MCM-41 looks at the straight cylindrical pores as they lie perpendicular to the viewing axis (courtesy of Thomas Pauly, Michigan State University).

1993: Moungi Bawendi of MIT invented a method for controlled synthesis of nanocrystals (quantum dots), paving the way for applications ranging from computing to biology to high-efficiency photovoltaics and lighting. Within the next several years, work by other researchers such as Louis Brus and Chris Murray also contributed methods for synthesizing quantum dots.

1998: The Interagency Working Group on Nanotechnology (IWGN) was formed under the National Science and Technology Council to investigate the state of the art in nanoscale science and technology and to forecast possible future developments. The IWGN's study and report, Nanotechnology Research Directions: Vision for the Next Decade (1999) defined the vision for and led directly to formation of the U.S. National Nanotechnology Initiative in 2000.

The progression of steps of using a scanning tunneling microscope tip to "assemble" an iron carbonyl molecule, beginning with Fe (iron) and CO (carbon monoxide) molecules ( A), joining them to produce FeCO ( B), then adding a second CO molecule ( C), to achieve the FECO2 molecule ( D). (H.J. Lee, W. Ho, Science 286, 1719 [1999].)

1999: Cornell University researchers Wilson Ho and Hyojune Lee probed secrets of chemical bonding by assembling a molecule [iron carbonyl Fe(CO)2] from constituent components [iron (Fe) and carbon monoxide (CO)] with a scanning tunneling microscope. (Image at left.)

1999: Chad Mirkin at Northwestern University invented dip-pen nanolithography ® (DPN®), leading to manufacturable, reproducible "writing" of electronic circuits as well as patterning of biomaterials for cell biology research, nanoencryption, and other applications. (Image below right.)

1999-early 2000's: Consumer products making use of nanotechnology began appearing in the marketplace, including lightweight nanotechnology-enabled automobile bumpers that resist denting and scratching, golf balls that fly straighter, tennis rackets that are stiffer (therefore, the ball rebounds faster), baseball bats with better flex and "kick," nano-silver antibacterial socks, clear sunscreens, wrinkle- and stain-resistant clothing, deep-penetrating therapeutic cosmetics, scratch-resistant glass coatings, faster-recharging batteries for cordless electric tools, and improved displays for televisions, cell phones, and digital cameras.

2000: President Clinton launched the National Nanotechnology Initiative (NNI) to coordinate Federal R&D efforts and promote U.S. competitiveness in nanotechnology. Congress funded the NNI for the first time in FY2001. The NSET Subcommittee of the NSTC was designated as the interagency group responsible for coordinating the NNI.

2003: Congress enacted the 21st Century Nanotechnology Research and Development Act (P.L. 108-153). The act provided a statutory foundation for the NNI, established programs, assigned agency responsibilities, authorized funding levels, and promoted research to address key issues.

Computer simulation of growth of gold nanoshell with silica core and over-layer of gold (courtesy N. Halas, Genome News Network, 2003)

2003: Naomi Halas, Jennifer West, Rebekah Drezek, and Renata Pasqualin at Rice University developed gold nanoshells, which when "tuned" in size to absorb near-infrared light, serve as a platform for the integrated discovery, diagnosis, and treatment of breast cancer without invasive biopsies, surgery, or systemically destructive radiation or chemotherapy. 2004: The European Commission adopted the Communication " Towards a European Strategy for Nanotechnology," COM(2004) 338, which proposed institutionalizing European nanoscience and nanotechnology R&D efforts within an integrated and responsible strategy, and which spurred European action plans and ongoing funding for nanotechnology R&D. (Image at left.)

2004: Britain's Royal Society and the Royal Academy of Engineering published Nanoscience and Nanotechnologies: Opportunities and Uncertainties advocating the need to address potential health, environmental, social, ethical, and regulatory issues associated with nanotechnology.

2004: SUNY Albany launched the first college-level education program in nanotechnology in the United States, the College of Nanoscale Science and Engineering.

2005: Erik Winfree and Paul Rothemund from the California Institute of Technology developed theories for DNA-based computation and " algorithmic self-assembly" in which computations are embedded in the process of nanocrystal growth.

2006: James Tour and colleagues at Rice University built a nanoscale car made of oligo(phenylene ethynylene) with alkynyl axles and four spherical C60 fullerene (buckyball) wheels. In response to increases in temperature, the nanocar moved about on a gold surface as a result of the buckyball wheels turning, as in a conventional car. At temperatures above 300°C it moved around too fast for the chemists to keep track of it! (Image at left.)

2007: Angela Belcher and colleagues at MIT built a lithium-ion battery with a common type of virus that is nonharmful to humans, using a low-cost and environmentally benign process. The batteries have the same energy capacity and power performance as state-of-the-art rechargeable batteries being considered to power plug-in hybrid cars, and they could also be used to power personal electronic devices. (Image at right.)

(L to R) MIT professors Yet-Ming Chiang, Angela Belcher, and Paula Hammond display a virus-loaded film that can serve as the anode of a battery. (Photo: Donna Coveney, MIT News.)

2008: The first official NNI Strategy for Nanotechnology-Related Environmental, Health, and Safety (EHS) Research was published, based on a two-year process of NNI-sponsored investigations and public dialogs. This strategy document was updated in 2011, following a series of workshops and public review.

2009-2010: Nadrian Seeman and colleagues at New York University created several DNA-like robotic nanoscale assembly devices. One is a process for creating 3D DNA structures using synthetic sequences of DNA crystals that can be programmed to self-assemble using "sticky ends" and placement in a set order and orientation. Nanoelectronics could benefit: the flexibility and density that 3D nanoscale components allow could enable assembly of parts that are smaller, more complex, and more closely spaced. Another Seeman creation (with colleagues at China's Nanjing University) is a "DNA assembly line." For this work, Seeman shared the Kavli Prize in Nanoscience in 2010.

2010: IBM used a silicon tip measuring only a few nanometers at its apex (similar to the tips used in atomic force microscopes) to chisel away material from a substrate to create a complete nanoscale 3D relief map of the world one-one-thousandth the size of a grain of salt-in 2 minutes and 23 seconds. This activity demonstrated a powerful patterning methodology for generating nanoscale patterns and structures as small as 15 nanometers at greatly reduced cost and complexity, opening up new prospects for fields such as electronics, optoelectronics, and medicine. (Image below.)

A rendered image of a nanoscale silicon tip chiseling out the smallest relief map of the world from a substrate of organic molecular glass. Shown middle foreground is the Mediterranean Sea and Europe. (Image courtesy of Advanced Materials.)

The NSET Subcommittee updated both the NNI Strategic Plan and the NNI Environmental, Health, and Safety Research Strategy, drawing on extensive input from public workshops and online dialog with stakeholders from Government, academia, NGOs, and the public, and others.

2012: The NNI launched two more Nanotechnology Signature Initiatives (NSIs)--Nanosensors and the Nanotechnology Knowledge Infrastructure (NKI)--bringing the total to five NSIs.

2013:
-The NNI starts the next round ofStrategic Planning, starting with the Stakeholder Workshop.
-Stanford researchers develop the first carbon nanotube computer.

2014:
-The NNI releases theupdated 2014 Strategic Plan.
-The NNI releases the 2014 Progress Review on the Coordinated Implementation of the NNI 2011 Environmental, Health, and Safety Research Strategy.

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This timeline features Premodern example of nanotechnology, as well as Modern Era discoveries and milestones in the field of nanotechnology. Early examples of nanostructured materials were based on craftsmen's empirical understanding and manipulation of materials. Use of high heat was one common step in their processes to produce these materials with novel properties.

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With the help of many education projects, introducing the nanoscale at school has never been easier - whatever the age of your students. Below are two experiments (for children aged 8+ and for 14- to 16-year-olds); many more resources are listed at the end of the article.

Dilution and the sense of smell

In the following experiment, suitable for ages 8 and above, food colouring is serially diluted, causing the colour and smell to fade gradually. The colour will fade more quickly that the smell, illustrating that even though our eyes cannot detect the chemical responsible for the colour, it is still present, as verified by the smell.

In the same way as we use our eyes to see large things and our nose to smell small things, nanoscientists use special tools to analyse (and manipulate) things at the very small scale: the nanoscale. Atomic force microscopes can feel and move individual atoms, while special surfaces with nanotextures on them can repel water extremely efficiently.

The experiment is taken from the 'Time for nano' project, which offers informal education materials about the benefits and risks of nanoscale research, engineering and technology. The website and materials are available in nine languages (Dutch, English, Finnish, French, German, Italian, Polish, Portuguese and Turkish). The project members - science centres across Europe - also offer 'nanodays', with demonstrations, experiments, games, meetings and discussions about nanotechnology. For more information, see the Time for Nano website.

Introduction

When introducing the activity, the following examples may help to illustrate how small the nanoscale is.

Our nails grow 1 nm each second.

The virus most usually responsible for the common cold has a diameter of 30 nm.

A cell membrane is around 9 nm across.

The DNA double helix is 2 nm across.

The diameter of one hydrogen atom is around 0.2 nm.

Encourage students to consider the things that they cannot see directly, for example the ozone layer, dyes in stained glass windows or the colloidal nature of milk.

Explain that the olfactory bulb of the brain is responsible for interpreting the smells that the nose detects. The olfactory bulb is strongly linked to a part of the brain that is responsible for remembering things, which is why certain smells can make us remember specific things clearly.

The students can calculate that in each tube, the food colouring is ten times more dilute than the previous tube. By the time they reach Tube 9, the original food colouring has been diluted to the level of one part of food colouring to a billion parts of water.

Materials

Some scented (this is important) food colouring

A Pasteur pipette

Nine test tubes, numbered 1-9.

Image courtesy of the Deutsches Museum

Procedure

1. Carefully fill each test tube with 9 ml of water.

2. Using the Pasteur pipette, carefully add 1 ml of food colouring to Tube 1. Mix the tube thoroughly.

3. Smell the contents. What does it smell of? Does it smell the same as the original food colouring?

4. Now take 1 ml of liquid from Tube 1, add it to Tube 2 and mix thoroughly.

5. Continue the process by repeating steps 3 and 4: dilute Tube 2 into Tube 3, Tube 3 into Tube 4, and so on.

At what point can you no longer see any colour in the tubes?

At what point can you no longer smell anything in the tubes?

How can you explain the difference?

The method you have just used is called a serial dilution. If you wanted, in just one step, to dilute 1 ml of the food dye to the same concentration as in Tube 9, how much water would you need?

Safety notes

Building a liquid crystal thermometer

Liquid crystals have properties between those of a conventional liquid and those of a solid crystal; for example, a liquid crystal may flow like a liquid, but its molecules may be oriented in a particular direction, as in a crystal. Liquid crystals are sensitive to external factors, such as temperature, and change their molecular arrangement when these factors vary. In response to a change in temperature, some types of liquid crystal (thermotropic ones) change colour as a result of a change in assembly.

In this experiment, students investigate colour changes in a thermotropic liquid crystal and then build their own liquid crystal thermometer. The protocol, which is suitable for students aged 14-18, was developed as part of the 'Nanoyou' project. Extensive supporting materials are available (in Danish, English, German, Italian, Portuguese and Slovak) from the project website.

The Nanoyou website is available in 12 languages and offers a range of free materials, including posters, presentations, card games, role plays and a teachers' training kit. This kit covers the fundamental concepts in nanoscience and nanotechnologies; applications of nanotechnologies; four laboratory experiments and a virtual experiment. Separate kits are available for the 11-13 and 14-18 age groups.

Schools that participate in the project work directly with leading European nanoscience research centres, receiving nanotech-related materials and taking part in workshops. Particular focus is given to ethical, safety and social implications, as well as present and future limits to scientific development. To learn how to get involved, visit the Nanoyou website.

Preparation

For this experiment, you will need four different mixtures prepared from three liquid crystals:

Cholesteryl oleyl carbonate (CAS number 17110-51-9, Sigma-Aldrich 151157; 25 g costs about €60)

Cholesteryl pelargonate (CAS number 1182-66-7, Sigma-Aldrich C78801; 100 g costs about €115)

Cholesteryl benzoate (CAS number 604-32-0, Sigma-Aldrich C75802; 25g costs about €40)

The instructions for preparing each of these liquid crystal mixtures ('Student synthesis procedure') and supporting material for teachers are available to download from the Nanoyou website.

Materials

4 pre-prepared liquid crystal mixtures

4 10-ml vials

A sheet of sticky-back plastic (used e.g. for covering books)

A spatula

Scissors

A permanent marker pen

A room thermometer

An A4 sheet of white paper

An A4 sheet of black paper

A water bath (or a hotplate, a Pyrex glass water container half filled with water, and thermometer)

A clothes peg

An A4 sheet of foam

An A4 sheet of black card

Gloves

Safety glasses

Paper tissue

Sticky tape (optional)

A hairdryer (optional)

Safety notes

Procedure

Preparing the liquid crystal sheets

Using Table 1, prepare four different liquid crystal mixtures, each of which is sensitive to different ranges of temperatures.

Liquid crystal mixture

Sensitivity temperature (°C)

Cholesteryl oleyl carbonate

Cholesteryl pelargonate

Cholesteryl benzoate

The finished liquid crystal
sheet
Image courtesy of the
'Nanoyou' project

1. Cut two pieces of sticky-back plastic (about 10 x 10 cm), peel off the backing paper and lay the plastic (sticky side up) on the bench.

2. Place 2-3 spatulas of the liquid crystal mixture 1 in the centre of one of the sheets. If the liquid crystal has solidified, warm the vial first with a hairdryer until the mixture has the consistency of honey.

3. Place the second piece of sticky-back plastic on top of the first piece, sticky side down. As you do this, gently press the middle to distribute the liquid crystal evenly, creating a thin layer of liquid crystal about 4 x 4 cm. Do not press too hard, otherwise the mixture will leak out; if it does, clean it up immediately with paper tissue.

4. Cut off any excess plastic and label the corner of the sheet with the number of the liquid crystal mixture (1).

5. Repeat the same procedure for liquid crystal mixtures 2-4.

Use the room thermometer to determine the temperature in the room you are in.

Could any of your liquid crystal mixtures be used to determine the room temperature? If so, which one?

Investigating the temperature changes

The liquid crystal sheet
before and after it has been
touched
Images courtesy of the
'Nanoyou' project

1. Place your four liquid crystal sheets on a sheet of white paper. Wait few seconds. What do you see?

2. Wearing gloves, press your finger against each of the liquid crystal sheets. (To make a fair comparison, you need to keep your finger on each liquid crystal sheet for the same length of time.) What do you see now?

3. Repeat the procedure on a sheet of black paper.

4. Record your observations in Table 2. (Tables 2-6 can be downloaded from the Science in School website.)

Why do you get different results when you test the liquid crystal sheets against white paper and black paper?

Did all four liquid crystal sheets display some colour? If not, why not? What could you do to make these sheets display colour?

Rub your hands together and test each of the sheets again. Do you see any difference?

Testing the liquid crystal sheets

Immersing the liquid crystal
sheet in the water bath
Image courtesy of the
'Nanoyou' project

1. Fill the water bath with cold water and raise the temperature to 15 °C.

2. Keep a thermometer in the water to check the temperature.

3. Place a sheet of black paper behind the water bath, to make any colours visible.
Note: the paper should not touch the hotplate.

4. Holding it with a clothes peg, immerse liquid crystal sheet 1 in the water bath (left). Can you see any colour?

5. Raise the water temperature to 23 °C. In Table 3, record the colours that you see as the temperature increases.

At what temperature do you start to see some colour in sheet 1? Does this correspond to the temperature predicted in Table 1?

Does the order of colours that you have recorded in the table above follow a particular pattern? If so, what pattern and why do you think this might be?

Take the liquid crystal sheet out of the water bath. Does it lose its colour immediately? If not, why not?

Imagine putting sheet 1 in a water bath of unknown temperature. If the sheet turned orange what temperature would the water be?

Place liquid crystal sheet 2 in the water bath (now at 23 °C) and raise the temperature to 30 °C. Record your observations in Table 4.

1. When the water temperature reaches 30 °C, test sheet 1 again. Can sheet 1 detect temperatures around 30 °C? Why/why not?

2. Place liquid crystal sheet 3 in the water bath (now at 30 °C) and raise the temperature to 35 °C. Record your observations in Table 5.

Place liquid crystal sheet 4 in the water bath (now at 35 °C) and raise the temperature to 40 °C. Record your observations in Table 6.

Was the colour sequence that you observed for sheets 2-4 the same as for sheet 1? Why/Why not?

When you take sheets 2, 3 and 4 out of the water bath, do they behave like sheet 1? If not, what is the difference? Why?

Which of the four liquid crystal mixtures would you use to see whether you have a raised temperature? Why?

Constructing the liquid crystal room thermometer

1. On the sheet of white foam, use the permanent marker pen to write the word 'NANO'. You will need to cover each letter with one of the four liquid crystal sheets, so make sure the single letters are large enough but not too large (see image below).

2. Cut the four letters out of the foam, leaving a single sheet of foam with holes spelling the word 'nano'.

3. Turn the sheet of foam over and cover each letter with one liquid crystal sheet, as follows:

The finished thermometer
Image courtesy of the
'Nanoyou' project

N - sheet 1
A - sheet 2
N - sheet 3
O - sheet 4

4. Using sticky-back plastic or sticky tape, fasten the liquid crystal sheets to the foam, making sure that each letter only exposes one sheet.

5. Cover the liquid crystal sheets with the sheet of black card, fastening it to the white foam. Your room thermometer is now complete.

Does your room thermometer show any colour? If not, why not?

If your thermometer does not show any colour, try placing it over a working laptop computer. It will demonstrate what we all know - that they heat up.

Your thermometer will last 3-6 months, after which it can be disposed of as normal waste.

How is this nano?

The properties of materials at the macroscale are affected by the structure of the material at the nanoscale. Changes in a material's molecular structures are often too small to see directly with our eyes, but sometimes we can see changes in the material's properties. Liquid crystals are an excellent example, in particular the type used in this experiment, since their optical properties (colour) change visibly as the temperature of the liquid crystal is changed. In nanotechnology, scientists take advantage of the peculiar properties of materials at the nanoscale to engineer new materials and devices.

Acknowledgements

Time for Nano is funded by the European Commission under the 7th Framework Programme.

The liquid crystal experiment published on the Nanoyou website was adapted from the 'Preparation of cholesteryl ester liquid crystals' - one of the many experiments listed on the website of the University of Wisconsin-Madison, USA - and from the 'Exploring materials: liquid crystals' activity developed by the Nanoscale Informal Science Education network.

The 'Nanoyou' (Nano for Youth) project is funded by the European Commission under the 7 th Framework Programme (FP7/2007-2013) under grant agreement 233433.

# data[].attributes.attachment_link.description
With the help of many education projects, introducing the nanoscale at school has never been easier - whatever the age of your students. Below are two experiments (for children aged 8+ and for 14- to 16-year-olds); many more resources are listed at the end of the article.