Fabrication and characterization of poly(N-isopropyl acrylamide)-gold nanoshell structures

Novel core-shell structures were presented here which consist of Poly(N-isopropyl acrylamide) (PNIPAM) microspheres as cores and gold as shells. The fabrication of these structures was convenient because the modifications to PNIPAM or gold nanoparticles (GNPs) were omitted. GNPs were attached to the surface of PNIPAM microspheres by means of electrostatic adsorption, and then acted as seeds to grow quickly into complete shells by optimizing the pH of the HAuCl4 solution to control the growth rate of gold nanoshells (GNSs). These structures combine the thermo-responsive behavior of PNIPAM microspheres with optical property of GNSs, and the localized surface plasmon resonance (LSPR) of the GNSs can be changed by adjusting the temperature of the PNIPAM microspheres which make them have great prospects for drug release. Their good biological stability in bovine serum albumin (BSA) and the LSPR located near 700 nm are expected for optical biosensors and optical analysis of whole-blood.