Sadegh Karimi

In this research, biocompatible iron oxide nanoparticles (𝛼 − Fe2O3 NPs) were prepared as an agent for photothermal (PTT) and photodynamic therapy (PDT) methods by combining green synthesis and hydrothermal methods. Then, by adding chitosan (CS) bio- polymer, the suspension of 𝛼 − Fe2O3 NPs became stable, and zeta potential analysis results proved it as well. Besides, various analyses such as transmission electron microscope, X-ray diffraction, UV-visible spectrum, and Fourier transform infrared spectrum were performed to determine the structural and optical characteristics of CS- 𝛼 − Fe2O3 nanocomposite. The average size of the spherical crystals of 𝛼 − Fe2O3 NPs was estimated at 43 nm by using the Williamson-Hall equation. The corresponding band gap value of 𝛼 − Fe2O3 NPs was estimated at 1.8 eV by drawing a Tauc diagram. Photothermal effects for several different concentrations of an aqueous solution of CS- 𝛼 − Fe2O3 nanocomposite were measured by an 808 nm laser with a power of 1 W/Cm2, and the concentration of 5 mg/ml as the optimal concentration was chosen for use in PTT. Besides, the value of the photothermal conversion efficiency of this nanocomposite was determined at 7% by using Roper's equation. In order to investigate the photodynamic properties of 𝛼 − Fe2O3 NPs, +a methylene blue probe was used to detect active oxygen species. Finally, by performing an MTT assay, the cytotoxicity of nanocomposite on AGS cells before and after laser irradiation was studied. Cell viability of these cells at concentrations of 250ppm and 500ppm, respectively 88% and 69%, were evaluated, which confirmed the PTT and PDT effects of this nanocomposite