Presentation Information
[1P49]Development of a Method for Evaluating Membrane Potential Using Voltage-Sensitive Dyes in Supported Lipid Bilayer Systems
*Hibiki Tsukada1, Ryugo Tero1 (1. Toyohashi University of Technology)
Supported lipid bilayers (SLBs) on SiO2/Si substrates are used to evaluate the membrane potential arising from substrate surface charges using voltage-sensitive dye Di-8-ANEPPS. SLBs were prepared by vesicle fusion from DOPC vesicles containing Di-8-ANEPPS. Ratiometric fluorescence imaging with 440/508 nm excitation was used to calculate the ratio R = I440/I508. R increased with KCl concentration (1.5–500 mM), indicating that the substrate-derived electric field is screened by ionic strength via Debye length shortening. When Di-8-ANEPPS was added post-SLB formation, R showed little change, suggesting that the electric field mainly affects the lower monolayer. An external voltage cell was also constructed by removing the backside oxide layer of the substrate and applying potential between the Si substrate and a Pt electrode. This system allows quantitative evaluation of interfacial potential in SLBs using voltage-sensitive dyes.