Creation of Raman-Active PEG Monolayers for Tracking Nanoparticles in Vitro
Y. Huang, Y. Cai, V. Swarup, S. Bishnoi
Keywords: Raman, SERS, SERS imaging
Abstract:We will present our work on the use of Raman-active, polytheylene glycol monolayers to stabilize gold nanoparticles in saline solutions and to track nanoparticles in vivo. Nanoshells possess great properties for use in cancer therapy, such as the ability to control their surface chemistry for improved biocompatibility / functionality and the tunability of their optical properties for nanoparticle-aided thermal ablation of cancer cells. These particles are often coated with a layer of poly(ethylene glycol) (PEG) to stabilize the nanoparticles in saline and buffer solutions; however, it can be difficult to characterize the conformation of the molecules on the particle surface. Previous work used Raman-active PEGs to quantify and characterize these monolayers, finding that the PEGs are close-packed on the surface of the particle in a brush-like configuration. Our group has taken this method one step further to use these Raman-active PEGs to track the uptake of nanoshells by Daphnia magna (a crustacean used by the EPA to monitor the toxicity of effluent), and within macrophage cell cultures. The Raman active-PEGs provide a non-intrusive method for identifying the localization sites of metal nanoparticles in vivo without the expense and labor required using transmission electron microscopy.