چكيده به لاتين
Graphene coated nanoparticles have attracted a great attention in recent years because of their high thermal stability and unique optical properties. In this thesis, the optical and photothermal properties of graphene coated nanoparticles including silica, gold, hollow gold-silver core using Mie, Gans and effective medium theories are investigated. Also, the temperature distribution of tumor tissue is calculated by bioheat transfer equations for various sizes and shapes such as nanosphere, nanorod and nanodisc. The extinction efficiency and temperature distribution of graphene coated gold nanoparticles show that gold nanorods because of high temperature rise during the laser irradiation are more suitable candidate for photothermal therapy (PTT) applications. Also, we show that the surface plasmon resonance (SPR) peak of graphene coated nanoparticles can be easily adjusted inside biological windows by increasing the graphene shell thickness and/or by changing their aspect ratio for spheroidal nanoparticles. For gold-silver alloy hollow nanoshell (Au-Ag HNS), its SPR peak can be tuned by controlling the alloy composition of Au-Ag.
Graphene shell increases the stability of Au-Ag HNSs in the presence of oxidants, acid and heating. The effects of laser intensity and the concentration of nanoparticles on the temperature rise in the tumor tissue are investigated. We also study the effect of number of graphene layers on the extinction efficiency and temperature rise of various shapes of graphene based nanoparticles. To achieve a comprehensive study, we describe the extent of thermal damage in tumor tissue by using the Arrhenius equation. Our findings introduce a new class of nanoagents which can be used in PTT applications.
