Antiviral candidates are assessed based on their ability to prevent infection in animal models and cell lines, but these infectivity screens typically do not yield information on the mechanism of action of the potential drug. For example, the severity of the recent Ebola outbreak spurred the development of several antiviral strategies including antibodies and channel blockers, but it is not known what part of the viral life cycle these compounds are affecting. We present a platform that probes the ability of antivirals to block the entry of enveloped viruses. This platform provides us with information on how antivirals impact viral entry kinetics without the need for live Ebolavirus and microfluidics enable us to screen multiple compounds simultaneously.
Our platform has two configurations, both of which use supported lipid bilayers (SLB). In the first configuration, SLB are embedded with the receptors used for viral entry and mimic the endosomal membrane. Virus-like particles (VLP) containing the Ebolavirus fusion protein are fluorescently labeled then passed over the bilayers. Binding and fusion of individual VLPs is tracked using total internal fluorescence microscopy. In the second configuration, the SLB is embedded with viral fusion proteins to mimic the viral membrane and fluorescently labeled vesicles containing the receptor are passed over the SLB. In either configuration, the data from particle tracking is used to study the fusion between the virus-like and host cell-like membranes to determine the fusion kinetics. Measuring kinetic parameters in the presence and absence of various antivirals can provide us with insight into their mechanism of action and will allow us to determine whether or not potential Ebolavirus therapeutics impact the binding or fusion of the virus.