Time-domain Modeling And Simulation Of Gold Nanoparticals Targeted Biological Tissue In Photothermal Treatment

Recently, the field of laser applications widely used in every aspect of medicine, as an irreplaceable mean of treating many diseases. Especially in tumor diagnosis and therapy,laser heat treatment opened up another road. Tumor photothermal therapy based on thermal effect generated by the laser interaction with biological tissue. Biological tissue absorbed the light and transformed into heat which is the key to treat cancer, promoting tumor photothermal therapy into clinical practice.Gold nanoparticles are affiliated in metal nanomaterials, which are recognized as a good multi-functional. It is widely favored by researchers in the field of cancer photothermal therapy which because of its Local Surface Plasma Resonance(LSPR). By controlling the size of the metal nanoparticles, morphology and structure, the surface plasmon resonance peak position can be adjusted to the near infrared region(NIR, 700 ~1300nm), which utlizes the water and biological tissue wavelenth with high permeability. Gold nanoparticles can quickly improve the photothermal conversion efficiency while dramatically minimize the heat damage to normal cells. The surface chemical affinity of gold nanoparticles makes it easy to bond with some specific protein,and to prepare functionalized nanoprobes which can target special tumor cells. Under irradiation of a certain laser power, the heat generated by gold nanoparticles enables the local temperature increasing quickly, thereby causing protein inactivation and then killing the tumor tissue. These features let gold nanoparticles to become a new means of cancer clinical treatment in the future.The model for cancer photothermal therapy which has important significance to research is not yet appeared. This article starts from the interaction between laser and biological tissue. We researched the thermal effects resulting on the absorption and scattering when light rejected biological tissue and established the transmission model through radiative transfer equation by transmission theoretical. Based on Pennes bio-heat equation, we established the thermal diffusion model. Using the finite element method(FEM) quantitatively calculated the value distribution of the photon density and temperature in biological tissue on time domain when the nano-gold targeted. In some extent, successfully simulated the light and temperature distribution in vivo after the laser irradiated a while time. Finally we constructed inhomogeneous phantoms to testify the transmission model and the thermal diffusion model. By compared the distribution of light and heat in different concentration of nano-gold, different exposure time and laser power value, we analyzed the effect of the different parameters on tumor therapy.It is of great significance that the results of this research which improves the process of the cancer treatment and the experiment in living treatment more reliability and safety.