The Partitioning of Resveratrol into the Nanorod-bound Surfactant Bilayer of Gold Nanorods

Jeremiah JohnstonJeremiah Johnston
Advisor - Dr. Lucas Thompson

Colloidal suspensions of nano-sized gold spheres have been known since the time of Michael Faraday, but only recently have anisotropic suspensions of gold been synthesized. These gold nanorods, from 20 to 100 nm in longitudinal length, are made by a seed mediated growth mechanism in the presence of a cationic surfactant, cetyltrimethylammonium bromide (CTAB). The CTAB persists beyond synthesis, and, as such, gold nanorods are encapsulated within a membrane bilayer, roughly 3 nm thick.

The CTAB bilayer of gold nanorods has attracted attention due to its potential use in targeted drug therapy. Research has indicated that small, non-polar molecules can enter in to the hydrophobic region of the bilayer by simple diffusion; once accumulated, the molecules can be released by photothermal excitation of the nanorod. Photothermal excitation is a product of the localized surface plasmon resonance (LSPR) of the nanorod, a process that describes how the nanorod electrons interact with light. Although much research has been conducted to investigate the release of small, hydrophobic molecules from the CTAB bilayer of gold nanorods, little research has been done to assess the stability of the intermolecular interactions with which the molecules are held in the membrane before release. Therefore, research has been conducted in the our lab to investigate a molecule that can be systematically altered to help clarify how the structural features of a small molecule dictate the thermodynamic preference for the hydrophobic region of the surfactant bilayer. Due to its biological relevance and ease of modification, resveratrol and its derivatives are being investigated to determine the equilibrium binding times and the partitioning coefficients of the molecules in the CTAB bilayer.