Novel applications of micro-shock waves in biological sciences

Spherical micro-shock waves of a few mm radii can be generated both in ambient air and in water by expending a small amount of energy (∼1 J). Various techniques such as focusing of laser beam, energy deposition using electrical discharge in water, micro-explosion of silver azide pellets and simultaneous actuation of piezo-ceramic/electrical crystal array can be used for creating micro-shock waves of requisite intensity. The nonlinear instantaneous pressure spike (1 MPa ∼ 100 MPa) generated by the micro-shock waves can be used in applications such as particle delivery systems for gene therapy, food preservation, wood preservation and conditioning, and also in cancer treatment. The visualization studies of micro-shock waves generated using laser beam focusing in ambient air, various types of micro-shock wave generators, the status of current research on various applications along with some experimental results on micro-shock wave-assisted particle delivery systems are discussed in this paper.