Light-Induced Temperature Transitions in Biodegradable Polymer and Nanorod Composites

A versatile method that utilizes infrared light (IR) to heat composites of gold nanorods and biodegradable polymers was developed. Poly(β-amino esters) (PBAEs) were synthesized by the conjugate addition of primary amines to diacrylates by mixing the liquid precursors and reacting overnight with stirring. Macromer A6 was synthesized through the reaction of diethylene glycol diacrylate and isobutylamine in a 1.2:1 molar ratio. Nanorods were grown through a mixture of cetyltrimethylammonium bromide (dAB), HAuCl4 - 3H 2O, silver nitrate, L-ascorbic acid, and a seed solution containing dAB, sodium borohydride, and HAuCl4 - 3H2O. The nanorods were imaged on a TEM at an accelerating voltage of 200kv by placing a drop of the nanorod/dichloromethane solution on a holey carbon coated grid. he heating was reversible with intermittent light exposure, meaning that the sample could be repeatedly heated and cooled with 5 minute intervals of light exposure and non exposure.