Decorating Bioelectronic Surface with Supported Lipid Bilayer to Study Viral Entry and More

There are two pathways for the entry of SARS-CoV-2: early (cell surface) entry and late (endosomal) entry. In both pathways it requires the initial binding of SARS-CoV-2 spike proteins with host cell membrane receptor (ACE2), followed by the cleavage of spike protein by either TMPRSS2 (early entry) or cathepsin L (late entry). We have previously demonstrated a supported lipid bilayer (SLB) containing native membrane component can maintain membrane fluidity and thus its biological functionalities, making SLB a desirable platform to recapitulate the conditions in vitro that support virus infection of a host cell. In this work, by forming SLB containing ACE2 receptors on a conductive polymer-based substrate, we have probed the two entry pathways of SARS-CoV-2 using electrical signal. Our results suggest the specific binding between spike protein containing virus pseudo particles and ACE2 receptors will increase membrane electrical resistance, while the fusion events catalyzed either by TMPRSS2 and cathepsin L will further increase membrane resistance. Our work shows the electrical readout of membrane properties based on SLB platform can be a powerful tool in detecting SARS-CoV-2 virus entry without the complications of working with live cells. In addition to viral entry, the versatile SLB based bioelectronic sensors are also applied to investigate the interactions between chemical permeation enhancer (CPD) and lipid bilayers, providing insights in the drug development against otitis media.