Thesis (M.Sc.) - Cairo University - National Institute of Laser Enhanced Science - Department of Laser Applications in Environmental Metrology, Photochemistry and Agriculture

Photothermal therapy has recently gained a considerable attention particularly after the revolution of nanomaterials and nanotechnology. The aim of the present work is to obtain the maximum photothermal response through investigating some effective parameters of spherical gold nanoparticles like type, size and concentration, as a preclinical study for efficient photothermal therapy. Tissue simulating phantoms based on agar and water media incorporated with two different types of spherical gold nanoparticles, uncoated particles capped with citrate and coated with silica shell, were built. Heat evolution for each type of nanoparticles was recorded in phantom matrix at different particle sizes with different concentrations following irradiation with low laser power of 250 mW, irradiance of 35.4 mW / cm2, and emitting at wavelength of 532 nm. Measurements demonstrated that uncoated spherical gold nanoparticles showed higher photothermal response than particles coated with silica shell. Particles with smaller sizes produced more heating effect than those with larger sizes. Only a critical average concentration of NPs is favorable for enhancing photothermal interaction. Temperature elevation depends on phantom type where higher temperatures were recorded from agar based phantom at each experimental condition. Exponential decay constants based on theoretical calculations demonstrated that laser attenuation increases with the continuous increase of particle size and concentration

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