(197p) Light Driven Ion Transport Using Biomimetic Membranes

Biomimetic membranes have a variety of applications in the environmental and biomedical realms. This work focuses on incorporating microbial opsins, proteins which pump ions in response to light, into lipid vesicles. Two opsins our group focuses on are Krokinobacter eikastus rhodopsin 2 (KR2) and Halorhodopsin (pHR), Na⁺ and Cl^-­ pumps respectively. The use of these proteins within biomimetic membranes can have applications in water desalination and optogenetics.

Transport rates of biomimetic membranes were investigated through the insertion of these proteins into asymmetrical vesicles. Using a liposome-based stopped flow technique, along with a fluorescent dye to identify changes in salt concentration, we can calculate the electrogenic transport of Na+, Cl^-, and other ions per opsin per unit time at fixed light intensity vectorially across the lipid membrane. This tool has allowed us to determine rate limiting steps of these proteins. Other methods, like Patch Clamp, offer additional insight into transport properties and brings us closer to future applications.