Effects of Applied Voltage on the Size of Phase-Separated Domains in DMPS-DOPC Lipid Binary Bilayers Supported on SiO<sub>2</sub>/Si Substrates

TL;DRAbstract

Supported lipid bilayers (SLB) are expected to offer a potential as biological devices utilizing biological membranes and membrane proteins. In this work, we investigated the effect of an external DC field on the phase-separated structures of gel phase and liquid crystalline phase in the SLBs of the DMPS-DOPC binary systems. The electric field was vertically applied to the SLB using a three-electrode system. The voltage apply of −1.0 V at the backside of the SLB increased the gel-phase domain size, while the voltage apply of +1.0 V decreased the domain size. This electric field effect is strongly related with the existence of PS lipids that is a negatively-charged lipid. Previously it was reported that the size of brain-PS-rich domain depends on the Ca2+ concentration. This implies that it is possible to change the domain size due to the change of the Ca2+ concentration near the surface of the SLB by applying the electric field.

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