Transmembrane proteins (TMPs) are Nature’s biorecognition, sensing, and transduction elements and critical components in biomimetic sensing. However, they are among the most challenging biomolecules to integrate into biosensors because they require a lipid bilayer to remain functional. Successful bilayer and TMP integration with bioelectronic devices would enable new capabilities in in vitro biosensing and biological actuation. To date, reconstitution of lipid bilayers onto sensing surfaces requires significant optimization of the abiotic/biotic interface. Nonetheless, current hybrid biotic-abiotic devices show great promise in biosensing, but even more so if arrays of TMPs tailored to sense specific targets could be produced. Such scale up is necessary for rapidly identifying the most sensitive protein sensors, providing a myriad of sensing elements that can monitor a variety of targets simultaneously, or producing enough data to enable machine learning approaches that can extend beyond biosensing into bioanalytical applications.

Our team has developed several approaches to integrate TMPs into supported lipid bilayers that functionalize organic bioelectronic devices. In this presentation, I will cover two methods. First, I will describe a technique to harvest membrane vesicles from live cells and using them to coat a surface of a bioelectronic device. Once formed, they serve as an authentic replica of the plasma membrane from a variety of cell types. I will describe two sensing examples using this approach: 1) measurements of ion channel activity for drug screening applications and 2) sensing of host-pathogen interactions, in particular, virus entry processes that lead to host cell infection. For the second approach, we use cell-free synthesis of proteins, in which cellular extracts are used to synthesize transmembrane proteins directly into lipid bilayers that coat the sensing surface. I will provide an example of ion channel sensing using TMPs formed by this approach.

Our goal is to build TMP arrays on bioelectronic devices that sense their functions and activity levels using the dual modality of electronic and optical means. The criticality of dual mode data collection is that, for transporters and ion channels, electrical means can be used label-free to read out flux of material across the membrane. Optical approaches offer the possibility to simultaneously obtain confirmation of folding with protein folding reporters, as well as obtaining structural information. Combining all these features into one platform offers a wealth of possibilities for many biosensing and bioanalytical applications and could be used to understand how the properties of the membrane influence the activity of TMPs.