Photothermal Effect of Gold Nanorods Impregnated Nanocellulose
Industrial Technology Research Institute, TW
Keywords: gold nanorods, photothermal effect, Bacterial Cellulose
Abstract:The plasmonic metal nanoparticles have attracted considerable attention in recent years with their tremendous applications in the field of catalysis, optics, and electronics. Specifically, rodlike gold nanoparticles exhibit many unique properties such as highly efficient photothermal conversion in near IR region, therefore these particles are favorable as photothermal therapeutic agents or contrast agent with minimal laser irritation. While for particle stabilization and size control, also as delivery vehicles, several substrate or matrices have been investigated including polyurethane and polyvinyl alcohols. Here in our study, renewable and highly biocompatible nanocellulose, which is synthesized by bacteria, is used as the substrate. Different from wood cellulose fibres, they have 3D network of nanostructure with fibres width between 60~100 nm. The novel nanocellulose were freeze dried and used here as a hydrophilic and easily hydrated matrix for use of impregnating gold nanorods. Well defined surfactant covered nanorods were prepared by seed mediated method and aqueous suspensions of Au nanorods were incorporated into nanocellulose membrane by dipping. Nanorods, Bacterial cellulose film, and dried rods impregnated nanocellulose film were characterized by UV-Vis spectroscopy and scanning electron microscope. Their temperature changes caused by photothermal conversions were recorded directly using IR camera. These results show that nanorods were well dispersed on the nanocelluoses and chemically stable. In addition, with low power laser (200 mW) irritation, the temperature of nanocellulose containing gold nanorods rose to over 70degrees Celcius in 20 sec. Thus, high photothermal conversion efficiency and being the stable nanocomposite makes it suitable for potential use in biomedical and optical applications.