Photothermal effect of Au nanoparticles and photothermal inactivation to saccharomycetes cell

Au nanoparticles (Au NPs) absorb light energy and convert it to thermal energy that transfers to environment. The temperature variation of Au NP and environment as well as photothermal conversion efficiency of Au NP are problems concerned by researchers. Herein the linear absorption of Au NP is simulated based on Mie theory, the surface plasmon resonance peak wavelength increases with increase of NP diameter, and the absorption reaches the maximum when the diameter is 70 nm. The heat transfer from an Au NP to water is simulated by finite element method, the thermal influence space is shown to be a sphere with radius of dozens of nanometers. The increase of Au NP temperature is fast in initial stage and slow in later stage of irradiation, the NP temperature saturates with elapse of irradiation time. The photothermal conversion efficiency is determined to be 0.7. Thermal effect of Au NPs to saccharomycetes cell is investigated through laser irradiation at 532 nm, the cell that adheres Au NPs are found to be killed by photothermal effect, which shows application of Au NPs in photothermal therapy.