With this experiment you will discover the properties of gold at the nanoscale. Gold (Au, atomic number 79) is the most malleable and ductile metal of all; it can be beaten to very thin sheets of material and rolled or bent as desired. This has been known and done for centuries. In this experiment you will investigate nanoparticles of gold or nano-gold! The properties of nano-gold are very different and it all has to do with the size of the nanoparticles. To download the protocol of the experiment and background information, as well as watching videos on how to perform it, visit: www.nanoyou.eu Translations to several languages are also availabe in the NANOYOU website.

1. Teachers Training Kit in Nanotechnologies Experiment Module A comprehensive training kit for teachers Experiment C Luisa Filipponi, iNANO, Aarhus University This document has been created in the context of the NANOYOU project. (WP4, Task 4.1) All information is provided “as is” and no guarantee or warranty is given that the information is fit for any particular purpose. The user thereof uses the information at its sole risk and liability. The document reflects solely the views of its authors. The European Commission is not liable for any use that may be made of the information contained therein.

2. Before you use this presentation This Power Point Presentation is part of the Experiment Module of the NANOYOU Teachers Training Kit in Nanotechnologies. MATERIAL INCLUDED IN THIS EXPERIMENT C PACKAGE : For teacher: EXPERIMENT C-TEACHER DOCUMENT NANOYOU VIDEO 2_GOLD COLLOID For students * : EXPERIMENT C-STUDENT BACKGROUND READING EXPERIMENT C-STUDENT LABORATORY WORKSHEET LEVEL OF EXPERIMENT : Advanced *These documents are available for the 11-13 and 14-18 age group in different languages DOCUMENTS CAN BE FOUND AT WWW.NANOYOU.EU This NANOYOU documents is distributed with Creative Commons Non-Commercial Share Alike Attribution, except where indicated differently. Please not that some images contained in this PPT are copyright protected, and to re-use them outside this document requires permission from original copyright holder. See slide 18 for details. DISCLAIMER : The experiments described in the following training kit use chemicals which need to be used according to MSDS specifications and according to 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.

19. Images credit Figure 1. Dependence of colour on gold size. (Image credit: L. Filipponi, iNANO, Aarhus University, Creative Commons Attribution ShareAlike 3.0). Figure 2 (top): Formation of plasmons in bulk metal (top) and in nanoparticles (bottom). (Image credit: D. Sutherland, iNANO, Aarhus University, Creative commons Attribution Non-Commercial ShareAlike 3.0) Figure 2(bottom): Transmission electron micrographs and UV—Vis spectra of gold nanoparticle colloids with various geometries: (top) spheres, (middle) decahedra and (bottom) rods. (Image credit: Reprinted from: Borja Sepúlveda et al., "LSPR-based Nanobiosensors", Nano Today (2009), 4 (3), 244-251, with permission from Elsevier). Figure 3 : Schematic representation of the preparation and response of LSPR biosensors based on refractive index changes. (Image credit: Reprinted from: Borja Sepúlveda et al., “LSPR-based Nanobiosensors”, Nano Today (2009), 4 (3), 244-251, with permission from Elsevier.) Figure 4 : A plasmonic colloidal nanosensor. (Image credit: reprinted with permission from Jin et al., Journal of American Chemical Society (2003), 125 (6), 1643- . Copyright 2003 American Chemical Society.) Figure 5 : (Left) Growth mechanism of nanospherical gold particles synthesised by reduction of aqueous AuCl4- by sodium citrate. (Right) TEM images of the dark intermediate showing an extensive network of gold nanowires which were isolated from the dark purple solution. (Image credit: reprinted with permission from Pong et al., J. Phys. Chem. C 2007, 111, 6281-7. Copyright 2003 American Chemical Society.)