Rapid Detection of SARS-CoV-2 Antigens and Antibodies Using OFET Biosensors Based on a Soft and Stretchable Semiconducting Polymer

Abstract

In the midst of the COVID-19 pandemic, adaptive solutions are needed to allow us to make fast decisions and take effective sanitation measures, e.g., the fast screening of large groups (employees, passengers, pupils, etc.). Although being reliable, most of the existing SARS-CoV-2 detection methods cannot be integrated into garments to be used on demand. Here, we report an organic field-effect transistor (OFET)-based biosensing device detecting of both SARS-CoV-2 antigens and anti-SARS-CoV-2 antibodies in less than 20 min. The biosensor was produced by functionalizing an intrinsically stretchable and semiconducting triblock copolymer (TBC) film either with the anti-S1 protein antibodies (S1 Abs) or receptor-binding domain (RBD) of the S1 protein, targeting CoV-2-specific RBDs and anti-S1 Abs, respectively. The obtained sensing platform is easy to realize due to the straightforward fabrication of the TBC film and the utilization of the reliable physical adsorption technique for the molecular immobilization. The device demonstrates a high sensitivity of about 19%/dec and a limit of detection (LOD) of 0.36 fg/mL for anti-SARS-Cov-2 antibodies and, at the same time, a sensitivity of 32%/dec and a LOD of 76.61 pg/mL for the virus antigen detection. The TBC used as active layer is soft, has a low modulus of 24 MPa, and can be stretched up to 90% with no crack formation of the film. The TBC is compatible with roll-to-roll printing, potentially enabling the fabrication of low-cost wearable or on-skin diagnostic platforms aiming at point-of-care concepts.

Electrochemical Immunosensors Based on Zinc Oxide Nanorods for Detection of Antibodies Against SARS-CoV-2 Spike Protein in Convalescent and Vaccinated Individuals

“… 16 The conventional methodology for serological determinations includes the traditional enzyme-linked immunosorbent assay (ELISA), 17 immunochromatographic Lateral flow assay (LFA), 18 and electrochemical biosensors. 19 , 20 …”

Discovery of a Phage Peptide Specifically Binding to the SARS-CoV-2 Spike S1 Protein for the Sensitive Phage-Based Enzyme-Linked Chemiluminescence Immunoassay of the SARS-CoV-2 Antigen

“…The LOD was reported for the surface plasmon resonance-based aptasensor (0.26 nM), 39 lateral flow immunoassay (LFIA) (>0.1 ng/mL), 40 , 41 the organic field effect transistor (OFET) (76.61 pg/mL), 42 nanomechanical sensor-based platform (1 ng/mL), 43 electrochemical immunosensor (19 ng/mL), 44 glycan-based lateral flow detection system (5 μg/mL), 45 photoelectrochemical aptasensor (72 ng/mL), 46 nanobody-based ELISA (0.147 ng/mL), 47 and portable amperometric immunosensor (0.15 ng/mL). 48 Apparently, the method we developed exhibits a similar LOD as the OFET 42 but outperforms most methods in sensitivity for the detection of spike antigens. The good sensitivity contributes to the screened phage #2 expressing the NFWISPKLAFAL peptide from the display library of the pIII phage, which has an excellent affinity to SARS-CoV-2 S1.…”

Nanofloating gate modulated synaptic organic light-emitting transistors for reconfigurable displays

“…5C ). In the future, upon changing the responsive units, different kinds of long afterglow sensors capable to respond to diverse stimuli can be used for light, thermal, sound, and biomolecular sensing in new active displays ( 45 ).…”