Fabrication of gold-coated silica nanorods for photothermal therapy based on phase separation of polymer blends

In this study, we demonstrated a novel on-substrate approach to fabricate gold-coated silica nanorods (GSNRs) with potential application in cancer hyperthermia therapy. Based on the circular nanodomains formed by phase separation of the polymer blend of polyphenylsilsequioxane (PPSQ) and polystyrene (PS), GSNRs were facilely obtained by means of conventional fabrication methods including reactive ion etching (RIE), e-beam evaporation deposition and lift-off. And it was simple and reliable to adjust the geometry of GSNRs by controlling the parameters of phase separation process and the thickness of the SiO2 layer. Surface modification of GSNRs with polyethylene glycol (PEG) was performed to increase their stability and biocompatibility in the aqueous solution. Due to the localized surface plasmon resonance (LSPR) of gold, there was an absorbance peak in near-infrared (NIR) region. The significant enhancement of heating effect indicated that GSNRs could rapidly and efficiently convert the laser energy into heat under 808 nm laser irradiation. In addition, the positive results of cytotoxicity test indicated that GSNRs were suitable for further in vivo applications. (paper)