Cells that are exposed to ultrasonic (US) energy, in the presence of ultrasound contrast agent microbubbles, may experience enhanced membrane permeability. If the effective dose of US exceeds some threshold, then cell lysis can result (lethal sonoporation), however for lower doses a transient enhancement of membrane permeability occurs (reversible or non lethal sonoporation). The merits of each mode are clear: lethal sonoporation constitutes a significant tumour therapy weapon, whilst its less intrusive counterpart, reversible sonoporation, represents an effective non-invasive targeted drug delivery technique. Until now, the mechanism of the dynamic interaction between microbubbles and cells has remained unknown. Moreover pores, which are the presumed mode of permeabilization have not been observed in a convincing fashion. We will demonstrate, for the first time, how an innovative hybridization of holographic optical trapping technology, together with the application of MHz pulsed US energy and subsequent high resolution observation using atomic force microscopy has been used to elucidate the fundamental mode for membrane permeabilization during sonoporation.