Publication date: Jun 17, 2026
A capacitive screen-printed electrode immunosensor operating in non-faradaic mode by dispensing redox probes was developed for the Coronavirus 2 Spike (S) protein. This new strategy enabled direct detection of the S protein by measuring changes in the electrochemical capacitance resulting from antigen-antibody interactions on the electrode surface, altering interfacial dielectric properties. To enhance analytical sensitivity and provide an electrode surface with attractive capacitive and conductive properties, an in-house graphite ink-based screen-printed electrode was developed and subsequently modified with a polypyrrole (PPy) layer in bulk-synthesized in the presence of Cetyltrimethylammonium bromide (CTAB). CTAB acted as a dispersing and structure-directing agent, promoting homogeneous distribution and guiding the PPy polymerization, resulting in a composite with improved charge density storage and high conductivity. Analytical signals of the S proteins in spiked serum were detected by measuring the Specific Capacitances taken from cyclic voltammograms. This capacitive immunosensor achieved a linear range from 1 to 100 ug/mL (R = 0. 989, p
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| Concepts | Keywords |
|---|---|
| Cetyltrimethylammonium | capacitive biosensor |
| Coronavirus | COVID-19 |
| Graphite | point-of-care |
| Immunosensors | polypyrrole |
| Spike |
Semantics
| Type | Source | Name |
|---|---|---|
| drug | DRUGBANK | Cetrimonium |
| disease | MESH | COVID-19 |
| disease | MESH | death |
| drug | DRUGBANK | Gold |
| disease | MESH | infection |
| drug | DRUGBANK | Potassium |
| disease | MESH | poisoning |
| drug | DRUGBANK | Activated charcoal |
| drug | DRUGBANK | N N-dimethylformamide |
| drug | DRUGBANK | Tromethamine |
| drug | DRUGBANK | Potassium nitrate |
| drug | DRUGBANK | Potassium Chloride |
| drug | DRUGBANK | Phosphate ion |
| disease | MESH | PBS |
| drug | DRUGBANK | Neon |
| drug | DRUGBANK | Water |
| drug | DRUGBANK | Ribostamycin |