Acoustic modulation of fluorescence spectra and mechano-sensitivity in lipid membranes

Solvation shell dynamics is a critical determinant of protein and enzyme functions. Here we investigate how the dynamics of the solvation shell changes for molecules embedded in lipid membranes during an acoustic impulse. Solvation sensitive fluorescence probes, Laurdan, embedded in multi-lamellar lipid vesicles in water, were exposed to broadband pressure impulses of the order of 1MPa peak amplitude and 10{\mu}s pulse duration. Corresponding changes in emission spectrum of the dye were observed simultaneously across two different wavelengths at sub-microsecond resolution. The experiments show that changes in the emission spectrum and hence the fluctuations of the solvation shell are given by the thermodynamic state change during the process. Therefore, the study suggests that acoustic fields can potentially modulate the kinetics of channels and proteins embedded in lipid membranes by controlling the state dependent fluctuations.