Journal: Clinics in Laboratory Medicine

Article Title: Alternative Methods to Detect Severe Acute Respiratory Syndrome Coronavirus 2 Antibodies

doi: 10.1016/j.cll.2021.10.007

Figure Lengend Snippet: Electrochemical assays. ( A ) The binding of antibodies to antigens coated on the surface of a working electrode impedes electron transport, and results in a quantitative change in impedance. This is measured using various electrochemical impedance spectroscopy techniques. For instance, as illustrated using Nyquist plots, the frequency dependence of the impedance is influenced by a change in the surface properties of the electrode when it is bound by an antibody. ( B ) Two approaches to functionalize a working electrode are shown. A graphene electrode is functionalized with noncovalently stacked pyrene-labeled antigens; such a graphene layer can also be coated on gold electrodes. Electrodes used in the Amperial platform are functionalized with native antigens entrapped in a conducting polypyrrole hydrogel using in situ electropolymerization. ( C ) A typical electrochemical electrode design comprising a working electrode, a counterelectrode, and a reference electrode.

Article Snippet: A low-cost coin-sized portable electrochemical impedance spectroscopy analyzer (Sensit, PalmSens, Houten, the Netherlands) connected to a smartphone was used for measurements.

Techniques: Binding Assay, Impedance Spectroscopy, Labeling, In Situ