Label-free and charge-sensitive dynamic imaging of lipid membrane hydration on millisecond time scales
Abstract
Lipid bilayer membranes are responsible for compartmentalization, signaling, transport, and flow of charge in living cells. Membranes self-assemble in aqueous solutions. Without a hydrating environment, membranes cannot exist. It is therefore surprising to note that the hydrating water is neglected in most membrane-related studies. We imaged membrane-bound oriented water by means of label-free second harmonic microscopy. We tracked, on millisecond time scales, membrane domain diffusion of condensed charged lipid domains, domain structure, and the spatial distribution of charge. Real-time electrostatic membrane potential maps were constructed using nonlinear optical theory. The spatiotemporal fluctuation in the membrane potential is surprisingly large and reveals the importance of charge fluctuations on membranes.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- April 2018
- DOI:
- 10.1073/pnas.1719347115
- Bibcode:
- 2018PNAS..115.4081T