Ctab-Coated Gold Nanorods for Controlled Photothermal Therapy
Fan-Hsuan Kao1*, Sandip Ghosh1, Thiago Lam Ho Ying1, Surojit Chattopadhyay1,2
1Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
2Biophotonics and Molecular Imaging Research Centre, National Yang-Ming University, Taipei, Taiwan
* presenting author:FAN-HSUAN KAO, email:jessie12397@yahoo.com.tw
The ability of metal nanoparticles (NPs), in particular Au, and Ag, to polarize and absorb electromagnetic radiation via the surface plasmons (SP) has opened up various applications in sensing, and therapy. The SP absorption could be spectrally tunes to absorb radiations in the visible or the infrared. The absorption of infrared (IR) radiation (700-1000 nm) provide ways to use these AuNPs in light guided therapy such as photothermal therapy. The use of IR enables, not only heating, but a deep penetration inside the tissues. In this work we have optimized CTAB coated Au nanorods (Au-NRs), with an aspect ratio of ~5, to absorb in the 780 nm range. We have used these AuNRs in a mixture with solid butter cube (24 x 75 mm2) to show a fast melting of the fat as a result of the optical absorption from a 785 nm laser (power density of 5.2 x 1011 W/cm2). By controlling the loading of the Au-NRs in the butter, it was possible to obtain a temperature rise of 5.6 °C in 20 min of laser irradiation, where only laser irradiation could produce less than 2 °C. A higher AuNR loading can raise the temperature higher. This is a model to demonstrate that these AuNRs could be used, not only to kill diseased cells by photothermal therapy, but also to degrade fatty acids at the molecular level to control obesity.
1.Dembereldorj et al., “Gold Nanorod-Assembled PEGylated Graphene-Oxide Nanocomposites for Photothermal Cancer Therapy”, Photochemistry and Photobiology (2014).
2.Huang et al., “Cancer Cell Imaging and Photothermal Therapy in the Near-Infrared Region by using Gold nanorods”, J. Am Chem. Soc (2006).

Keywords: gold nanorods, surface plasmon absorption, absorption spectroscopy, opto-thermal effects, phothermal therapy