Fig. 2: Optical and electrical characterization of the infection-on-chip platform’s components and functionalities.
a We used FRAP to characterize the mobility of SLBs formed on PEDOT:PSS surfaces. Shown here is one exemplary photobleached spot recovering over time from three independent experiments, indicating a mobile SLB. The cartoon representation is meant to provide a conceptual illustration of the technique. Indeed, our SLB was composed of both fluorescent and non-fluorescent lipids, and the fluorescence seen in the images is reflective of only the doped in R18 dye. b TIRF was used to confirm the existence of ACE2 receptor in SLBs: only fluorescently labeled VPPSpike are visible at the SLB interface when bound to ACE2 receptors, while no fluorescently labeled VPPΔenv were observed near the SLB due to the lack of binding interaction with ACE2 receptors on SLB. Shown here is one exemplary comparison from three independent observations. c EIS was used to characterize the electrical properties of an SLB on a PEDOT:PSS electrode. An SLB is modeled electrically as a capacitor and a resistor connected in parallel, hence its resistance (Rm) can be extracted by fitting to the RC(RC) circuit as shown. It can then be normalized by the area of electrode. All scale bars in this figure represent 20 μm.
