Photothermic Inactivation of Microorganisms at Relaxation of Highly Excited States of Sensitizers
This study demonstrates the susceptibility of planktonic bacteria Escherichia coli and Bacillus subtilis to inactivation by shock acoustic waves arising from the rapid formation and collapse of vapor bubbles in the medium locally heated to boiling point. Local heating of the medium occurred due to heat release through relaxation of highly excited electronic states of exogenous molecules of organic dyes. Dyes molecules were excited by nanosecond laser pulses. Highly excited electronic states were formed as a result of stepwise absorption of two quanta of laser radiation. The dependency of the efficiency of microorganism inactivation on dye concentration, the excitation power density and the distance from the shock wave source was studied.