Hydrogel-Enhanced Supported Lipid Bilayers (SLBs) Offer Greater Stability and Functionality in Bioelectronic Devices

Supported lipid bilayers (SLBs) have emerged as an indispensable material to functionalize the surface of bioelectronic sensors that facilitates the exploration of cellular membrane interactions with a wide range of molecules. SLBs accurately mimic the structure, composition, and diffusive properties of natural membranes, providing a biomimetic experimental model. Particularly noteworthy is the compatibility of SLB bioelectronics with electrochemical impedance spectroscopy (EIS), allowing for real-time monitoring of changes in impedance across SLBs. Such measurements provide valuable insights into changes in membrane properties, drug interactions, and the behavior of embedded proteins and channels. However, one drawback of these sensors currently is their vulnerability and limited shelf-life that impedes their broader application.<br/>In this study, we combine hydrogels with SLB bioelectronic devices and show that the usable shelf-life of these devices can be extended significantly. Our approach exploits a range of hydrogels, each with unique characteristics that enhance system versatility. PEGDA, a UV crosslinked hydrogel, enhances the stability of both model POPC SLBs and native component SLBs. Other hydrogels, such as poloxamer based thermally reversible gel, and chitosan based chemically crosslinked gels, show potential for preserving UV- and temperature-sensitive components within the SLBs. Overall, this strategy extends the shelf life of the SLBs from a single day over 45 days, all while preserving the electrical signal integrity and functionality of proteins within the SLBs. This hydrogel-enhanced approach not only facilitates longer sensing periods, but also enables the long-distance shipping of functional SLB-based devices, necessary steps for translation to the field.<br/>In addition to enhancing the shelf life and stability of the SLB-functionalized bioelectronic devices, the integration of hydrogels also boosts their functionality. The hydrogel layer not only facilitates improved stability but also enables the use of cell-free expression of proteins directly into the membrane. This expands the utility of our method, creating opportunities for more comprehensive investigations into the behavior of specific proteins and their responses to various agents within a highly stable, extended-lifespan SLB-based bioelectronic system. This research lays the groundwork for the development of sophisticated hydrogel-enhanced SLB systems capable of operating in complex environments, bringing us closer to the construction of advanced devices such as electrode arrays, sensors, and biomimetic devices, and expanding the scope of bioelectronic applications in biomedical research and beyond.