STUDENT LAB GUIDE
SPORTS DRINKS AND NANOTECHNOLOGY
INTRODUCTION AND INSTRUCTIONS
WHAT IS NANOTECHNOLOGY AND THE NANOSCALE?
Nanoscale technology involves using particles ranging from 1nm to 100nm (one
nanometer is equal to one billionth of a meter). Nanoparticles are so small that they
cannot be seen with the naked eye or even a light microscope. One very unique
feature of nanoparticles is that at the nanoscale their physical and chemical properties
are very different compared to larger samples of the same substance. This is called the
oligodynamic effect. For example: some may change colors and become chemical
indicators, some may become insulators, some may have different melting points and
some can act as semiconductors.
Nanoscale properties have enabled many organisms to evolve special nanoscale
mechanisms that have been part of the natural world for a long time. Two examples are
the glue that mussels secrete which bind them to rocks in the water and the tiny hairs
on the feet of geckos which allow them to climb on slick glassy surfaces.
WHAT IS NANOGOLD AND HOW DOES IT WORK?
One important nanoparticle, nanogold, has been around since the Middle Ages. Artists
have used nanogold to create the various colors in stained glass. By adding different
sizes of nanogold particles to the glass they were able to create all the different colors
visible in a stained glass window. For example: the red glass contains particles around
20nm across, 30nm particles produce pink glass, and 80nm particles produce orange
glass. These artists, however, had no way to measure the size of the particles or to
know the scientific explanation behind the variation of the colors.
Nanogold color depends on the size and shape of the nanoparticles and the distance
between them. The color may appear as either red or orange or blue.
The phenomenon called surface plasmon resonance (SPR) accounts for these
variations. Light shining on the surface of a metal produces surface plasmon, a
condition in which a group of electrons move back and forth together across the metal
surface. The electrons ripple back and forth not unlike waves of water moving across a
pond. Resonance occurs in the plasmon when the electrons are moving at the same
frequency as the light. In resonance the electrons absorb and scatter light, thus
producing various colors.
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Nanogold particles resonate at frequencies within the visible spectrum. The smaller
particles absorb and resonate at the range of the spectrum where the purple, blue,
green and yellow wave lengths of light are located and therefore appear red. The larger
nanogold particles absorb and resonate at the range of the spectrum where green,
yellow and red wave lengths are found so these particles appear blue.
The Nanogold/Electrolyte Lab utilizes this technology. The nanogold particles serve as
a biosensor, which works in the following way:
1. The negative charge on the surface of the nanogold particles repels other
neighboring nanogold particles, thus keeping the particles small.
2. When an electrolyte (salt) is dissolved in water, cations (ions with a positive charge)
and anions (ions with a negative charge) are formed.
3. The positive cations from the electrolytes freely bind to the negative surface of the
nanogold particles, creating a neutral cation-nanogold particle.
4. As more and more cations bind to the nanogold particles’ surfaces, they begin to
accumulate and form clusters.
5. The clusters are much larger than the original nanogold particles.
6. The increase in size causes a color change in the solution.
7. The net size of the nanogold particles have increased from the formation of clusters
and the surface plasmon resonance has changed, thus changing the wave length of
absorption.
8. The end result is a different color that is consistent with the size-color effect.
Electrolytes (salts) are made of two parts (ions), one
with positive charges (cations) and the other with
negative charges (anions).
When electrolytes are dissolved in water, the cation
and anion parts split up. Each gold nanoparticle
carries a negative electrical charge on its surface
due to how it was made, which makes the individual
gold nanoparticles repel each other. As electrolytes
are added to the nanoparticle solution, the cations
(positive) are attracted to the nanoparticles
(negative), and effectively “cancel out” some of the
negative charge that prevented the gold
nanoparticles from touching. Thus they are able to
come together and clump, leading to larger
nanoparticles.
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WHY DO WE NEED ELECTROLYTES?
When you exercise, you sweat. When you sweat, you lose water and electrolytes
(salts). All muscle cells use sodium to close or contract the cells and potassium to relax
the cells or stop the contraction. Calcium starts the closing process with sodium
managing the actual closing. Magnesium starts the relaxing process with potassium
managing the relaxing process within the cell. In order for the human body to function
properly under physical stress, all four of the mineral electrolytes (sodium, potassium,
magnesium and calcium) are absolutely required. If they are not replaced, you could
have a cramp or arrhythmia (irregular heart beat). Prolonged effects of improper
replenishment can result in serious injury such as a heart attack or circulatory shutdown and even death.
To help replenish the electrolytes lost in sweating, sports drinks may be consumed.
Nanotechnology can be used to test various sports drinks to determine which have the
most electrolytes. By this method, you can determine which of these sports drinks might
be the best choice to consume after exercise.
RE-READ THE INTRODUCTION
Materials:
Plastic cups
Vial containing pre-made gold nanoparticle solution
Microcentrifuge test tubes
Microcentrifuge test tube holder
Plastic pipets
Black Sharpie
Piece of white paper
Various electrolytes
Distilled water
Bucket for liquid waste
Student Lab Guide----Sports Drinks and Nanotechnology
Handout A, Handout B
Table 1: Data Collection
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PROCEDURE:
1. Complete Handout A and read through ALL the steps before you begin the Lab.
2. Label 7 microcentrifuge test tubes using the black Sharpie with the letters A, B, C, D,
E, F, G.
3. Place each microcentrifuge test tube in the test tube holder.
4. Label 7 plastic pipets using the black Sharpie with the letters A, B, C, D, E, F, G.
5. Label 1 additional plastic pipet nanogold colloid using the black Sharpie.
6. Use the nanogold colloid pipet to load one ml (approximately 20 drops) of the
nanogold colloid to each of the labeled A through G test tubes.
7. Label an additional microcentrifuge test tube CONTROL and add 1.5ml
(approximately 30 drops) of the nanogold colloid using the nanogold pipet.
8. Add the sports drink test samples to the test tubes as follows: Use the pipet labeled
“A” to add 0.5ml (approximately 10 drops) of the sports drink in the plastic cup labeled
“A” to the test tube labeled “A”. Repeat the process using pipet “B”, sports drink “B”
and test tube “B”; follow the same process for C, D, E, F, G.
9. Read the instructions under Table 1, observe the sample colors approximately 10
minutes after the nanogold colloid has been added to the samples, and enter your
findings in Table 1: Data Collection.
Prepared by: Dr. Debbie Payne, Ruth H. Liddell, Shirley K. Scarbrough
Alabama State University, Math, Science Partnership, Spring 2013
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