Development and characterization of biomimetic membrane architecture for single molecule sensors and electrophysiological studies

An artificially reconstituted lipid bilayer is a useful platform for both electrophysiological studies and sensing applications. We used this platform to study a number of channel proteins and pore forming peptides. Specifically, comprehensive channel experiments with variants of the Alzheimer's disease associated peptide beta-amyloid and its wild types were performed. Through these experiments we were able to show that the glycine zipper plays an important role in the channel formation of amyloid peptides.;We also investigated the development and modification of lipid bilayer platforms for channel experiments and channel protein-based sensing applications. These applications have traditionally been plagued by the intrinsically short lifetime and instability of the membrane, making channel experiments and sensor development problematic. To address these problems, an ABA triblock copolymer was used to form biomimetic membranes and incorporate channel proteins. Although completely synthetic, the membranes formed using this polymer where similar to lipid membranes with respect to protein incorporation and function.;Another approach to achieve increased stability was devised in hydrogel encapsulated membranes (HEM). The membrane lifetime and stability were significantly enhanced with this technique. To further stabilize HEM, we functionalized lipid headgroups to enable conjugation of the membrane to the hydrogel, resulting in a long lived hydrogel conjugated membrane (cgHEM) that remained stable for over 11 days. Further investigation of the cgHEM also provided physical insights into how hydrogel encapsulation stabilizes a solvent annulus which is crucial for membrane stability and longevity. These observations were further proven by immobilizing the solvent annulus through conjugation of the hydrogel to a solid substrate.;We have also developed a new method for the transport and long-term storage of a membrane precursor (MP) using a high freezing point solvent. Upon freezing MP, the lipid bilayer self-assembly process is halted, allowing indefinite storage and transportation in the robust frozen state. After thawing, membrane self-assembly resumes, ultimately resulting in fully functional membranes. In combining the MP system with an inexpensive chip, we demonstrate the possibility of an inexpensive, disposable, and shippable channel measurement system which is completely accessible to a lay audience.