Thermal Distribution of Silica Coated Gold Nano Rods in Tissue-Like Phantom as In Vitro Model for Plasmonic Photo Thermal Therapy.
Seyed Jamal Ashrafi 1*, Fatemeh Yazdian1, Ashraf Sadat Hatamian Zaremi1 , Javad Mohhamadnejad1 and Rassoul Dinarvand 2*1Department of Life Sciences Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran , North Kargar Street, Tehran, Iran.
2Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1417614411, Iran.
Corresponding Author E-mail: sj.Ashrafi@ut.ac.ir
Abstract: While plasmonic photo thermal therapy (PPTT( as local hyperthermia could act at a high temperature (56°C), It shows more specificity and a shorter time of heating in comparison to traditional (local, regional, and whole body) hyperthermia. But In order to use this advantage, some critical properties of three key parts of PPTT i.e. laser, nanoparticles and tissue condition need optimization. Herein relation between laser power and nanoparticle concentration to induce and stabilize temperatures in phantom is investigated. Gold nanorods as plasmonic nanoparticles were synthesized, purified and coated with silica. Sign characterization shown Nanorods with a length of 40nm, a width of 10.5nm and about 18nm silica coat Plasmon peak was observed at 812nm. Polyacrylamide gels were selected as tissue-equivalent materials. Different concentrations of SiGNR were mixed with polyacrylamide gels. Laser irradiation was done by diode laser 810 nm with power density of 2W/cm2 for 2 min. Laser power density and nano particle concentration were selected as variable parameters. Thermal changes were monitored online and recorded by an infrared camera. The results show that lower concentrations of SiGNR are more suitable for producing uniform thermal distributions in phantoms, while reducing the laser power decreases the heating rate but thermal distribution is not completely uniform. Frequently turning the laser on/off could induce and stabilize suitable temperature ranges. uniform thermal distribution in tumor, heating rate and prepared constant defined temperature for defining time are three qualitative parameters that need optimization during plasmonic photo thermal therapy. Laser, plasmonic nano particles and tissue are three players of PPTT that must optimize so sufficient heat (qualitative and quantitative) prepares against tumor with the least affect toward healthy tissue.
Keywords: silica coated gold Nanorods; polyacrylamide phantom; NIR laser; hyperthermia; thermal distribution Back to TOC