Real-time imaging of plasma membrane dynamics in sonoporation: from perforation to recovery

Abstract

BACKGROUND, MOTIVATION AND OBJECTIVE: To properly harness sonoporation for therapeutic applications, it is unarguably vital to characterize the fundamental biophysical processes involved. Of particular relevance are two membrane-level processes that epitomize the notion of sonoporation: 1) how membrane perforation is induced by ultrasound-microbubble interactions, and 2) how the membrane remodels itself following an episode of sonoporation. Acquiring direct observations of these processes is however not a straightforward task (ironically, these membrane-level events have yet to be convincingly demonstrated in-situ). In this investigation, our aim is to acquire the first series of direct evidence on the time course of membrane perforation and recovery in sonoporation. In particular, we seek to unravel the time-varying surface topography of sonoporated cell membrane in-situ. STATEMENT OF CONTRIBUTION/METHODS: A real-time imaging platform for monitoring of cell-microbubble interactions was first developed, and it was a composite system that coupled a 1 MHz ultrasound module to a laser scanning confocal microscope. A nose-cone shaped waveguide (1” diameter, 7.5 cm height) was devised to align the ultrasound beam focus to the microscope’s imaging plane. This waveguide was angled at 45 deg. with respect …