Suspended lipid membranes, also known as black lipid membranes (BLMs), are useful synthetic platforms for observing diverse cellular mechanisms including ion channel activity, protein-drug interactions, and membrane structural transformations. However, BLMs formed from fluid lipids lack the stability needed for many biosensing applications. Using electrophysiological measurements, we have shown that by doping a 1,2-diphytanoyl-<i>sn</i>-glycero-3-phosphocholine (DPhPC) BLM with crosslinkable, methacrylate monomers and a UV-activated initiator, it is possible to create a poly(methacrylate) scaffold in the bilayer that greatly enhances its mechanical and electrical stability. To support the activity of ion channel proteins in these BLMs, we are systematically varying the bilayer composition in an effort to identify an optimal combination of enhanced bilayer stability and retained bilayer fluidity. We are studying the effects of UV irradiation and polymer scaffold formation on membrane fluidity and electrical properties, using electrophysiology and single-molecule tracking (SMT) of a fluorescent probe, Rhodamine-DOPE, in DPhPC BLMs formed across planar microapertures (150- 200 µm diameter). Initial results show that apparent lateral diffusion coefficients in polymer-scaffolded (PS)-BLMs were five-fold lower than those observed in pure lipid BLMs, and PS-BLMs were sufficiently fluidity to support the activity of gramicidin ion channels. In addition, PS-BLMs showed a high level of electrical stability over pure BLMs and were resistant to capacitive breakdown. Thus PS-BLMs provide a structurally robust and sufficiently fluid platform for ion channel-based biosensing.<br/>

Single molecule tracking across polymer scaffolded black lipid membranes

251st National Meeting (2016)

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