Ultrasound may be exploited for the treatment of microbial diseases.

In view of the global problems caused by drug-resistant bacteria and pathogenic viruses, current methods are not satisfying. It is urgent need for novel antimicrobial strategies. It has now been confirmed that illumination of the photosensitizers (PS) by light at an appropriate wavelength can lead to inactivation of the pathogen through the production of highly reactive free radical species, which induce oxidative damage to lipid, proteins and DNA/RNA; But for the limited tissue penetration of visible light and the problems of systemic light delivery, the use of light in treatment of microbial diseases is still in its infancy. Recently, it has been found that some PS also produces free radicals on irradiation with ultrasound whose mechanism is similar to Laser. Ultrasound can penetrate into tissue more deeply than light and can be focused into a small region to activate some PS. Due to the unique advantage of ultrasound and mechanism of producing free radicals similar to light, we hypothesized that ultrasound may be exploited for the treatment of bacterial and virus infectious diseases. We proposed a new concept of "sonodynamic antimicrobial chemotherapy (SACT)", and hypothesized that it may be a promising novel antimicrobial strategy.