Thirsty for Gold
The phenomenon called surface plasmon resonance explains the brilliant, shiny "gold" color of bulk gold.Copyright 2004 Microsoft Corporation, One Microsoft Way, Redmond, WA 98052-6399 USA. All rights reserved.
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. Using some basic chemistry and physics principles, students develop a conceptual understanding of how gold nanoparticles function. They also learn of important practical applications in biosensing.
Gold nanoparticles have been used for centuries to make vibrant stained-glass colors. More recently, engineers have developed applications in the field of biosensing. Because of their inherently small size, nanoparticles exhibit superior surface controlled electronic and optical properties. They also allow for easy surface manipulation to engineer surfaces for particular applications. Engineers have developed many methods for attracting particular DNA base, controlling surface charge for cation/anion attraction and created biological coatings to bind to particular hormones.
After this activity, students should be able to:
- Describe how nanoscale gold interacts with light differently than bulk gold.
- Explain how the color of gold nanoparticle solutions is dependent on particle or cluster size.
- Explain how nanoscale gold can be used for sensing chemical and biological agents.