Laser-induced Acoustic Breakage of Tobacco Mosaic Virus

Abstract

CAROME, in a recent letter¹ commenting on our article on the mechanical disruption of tobacco mosaic virus² by laser-induced transients, suggests that the effect we detected may have been caused by a number of complicating factors related to pulse reflexions and/or cavitation of the suspending medium. Although the points made by Carome are certainly valid we would like to clarify the issue. We obtained TMV breakage in all of the cases mentioned by Carome; namely, pulses reflected back through the liquid sample at a water-to-air interface; or totally transmitted without reflexion; or transmitted into a finite thickness water layer and then reflected at a water–air interface. The fact that breakage was obtained with totally transmitted pulses, which corresponds to transmission of a positive pressure transient through the virus suspension, is particularly important. As mentioned in our previous communication², the effect was enhanced when the reflexions occurred at the liquid–air interface of the virus suspension. Breakage was not, however, significantly increased by reflexions (including negative transients) generated at other interfaces in the system. The details of the hydrodynamical analysis of the stress engendered in the TMV by the laser-induced acoustic transient have been presented in greater detail elsewhere³.