Paper BI-ThP16
Synthesis Biocompatible Gold Nanorods

Thursday, October 18, 2007, 5:30 pm, Room 4C

The ability to tune the optical properties of metal nanoparticles by changing their size and shape make them an ideal and diverse tool for biomedical applications. Challenges remain to utilizing nanomaterials for in vivo medical applications. By selecting benign compounds as synthons for nanoparticles it is predicted that toxicity can be greatly reduced. Furthermore, the resulting synthetic waste can be minimized and the process made more environmentally friendly and safe. We report nanoparticle-liposome composite materials that are stable, water soluble, and anticipated to be benign. Specifically, soy lecithin has recently been used to synthesize particles with these characteristics. These lipids are a cheap, readily available and non-toxic ligand for the synthesis of gold particles. Soy lipids form liposomes that function as nanoreactors in which particles form. We aim to change the shape and size of particles by manipulating these nanoreactors allowing for tuning of their optical properties. The optical applications of gold nanoparticles are of particular interest. Design of particles with a particular shape and size are desirable for use in vivo. Rod shaped nanoparticles absorb near infrared light that penetrates into deep tissue and presents a unique possibility to locate and treat maladies non-invasively. Using soy lecithin as a ligand, particles of a uniform size distribution can be created with reproducible results. Soy components have also shown promise for shape control of particles. Using these naturally occurring ligands, a series of gold nanoparticles have been synthesized and characterized. The resulting nanoparticles are stable for long periods with little aggregation. UV-Visible spectroscopy and transmission electron microscopy have been used to characterize size and shape of the resulting nanoparticles. It is believed a plethora of components contained in soy could also play a role in particle synthesis. We have isolated a small number of these compounds and identified them using NMR and mass spectrometry. Active components have been identified which contain linoleate tails. Ethyl linoleate has been positively identified and its ability to effect the shape of the gold nanoparticles is under study. Synthetic ethyl linoleate is being used in parallel with ethyl linoleate recovered from the soy lecithin to reveal its role in shape control of the nanoparticles as well as the rate of reaction in particle synthesis.