In order to demonstrate the platinum nanoparticles electrodeposition onto the LIG electrodes, a scanning electron microscopy analysis was performed using a scanning electron microscope SU5000 under the following conditions: 5 kV, 40 spot size, 50 Pa low vacuum, and magnification of 0.5, 2.5, 5, and 15 k.
To corroborate the presence and distribution of biotinylated hACE2 and recombinant S protein-RBD onto the LIG-nPt electrode surface, confocal microscopy images were taken on a Leica SPE confocal (Leica Microsystems, Wetzlar, Germany) at the Clemson Light Imaging Facility (Clemson Division of Research, Clemson University, Clemson SC, US). Biotinylated hACE2 was directly labeled with AlexaFluor™ 488 Microscale Protein Labeling Kit (Invitrogen™, green, λ 495/519 nm). Recombinant S protein-RBD was directly labeled with AlexaFluor™ 555 Microscale Protein Labeling Kit (Invitrogen™, orange/red, λ 555/565 nm).
To corroborate the presence and distribution of biotinylated hACE2 and recombinant S protein-RBD onto the LIG-nPt electrode surface, confocal microscopy images were taken on a Leica SPE confocal (Leica Microsystems, Wetzlar, Germany) at the Clemson Light Imaging Facility (Clemson Division of Research, Clemson University, Clemson SC, US). Biotinylated hACE2 was directly labeled with AlexaFluor™ 488 Microscale Protein Labeling Kit (Invitrogen™, green, λ 495/519 nm). Recombinant S protein-RBD was directly labeled with AlexaFluor™ 555 Microscale Protein Labeling Kit (Invitrogen™, orange/red, λ 555/565 nm).