Laser-induced shock wave effects on red blood cells

The trend for laser-based medical therapies has been towards short-pulse, high-peak power lasers. A consequence of using these lasers is the production of pressure waves that may propagate deep into tissue. Our previous experiments have concentrated on describing these effects and examining methods for measuring laser-induced shock waves. These two approaches were combined to study the effects of well-defined shock waves on red blood cells in vitro. Red blood cells were exposed to shock waves in capillary tubes covered with either latex or polyimide. The latex was deformed by the expanding plasma bubble whereas the polyimide was not. In the latex experiments where the cells were exposed to the bubble expansion in addition to the shock waves, damage to the cells was much greater. When the cells were exposed only to the shock waves through the polyimide, much less damage was apparent. This is the first clear example of the separation of different mechanical effects on tissue damage. In addition, the shock wave damage is not as significant as the damage caused by the bubble expansion.