Biofunctionalization of Graphene‐Based FET Sensors through Heterobifunctional Nanoscaffolds: Technology Validation toward Rapid COVID‐19 Diagnostics and Monitoring

PICCININI, ESTEBAN; FENOY, GONZALO E.; CANTILLO, AGUSTÍN L.; ALLEGRETTO, JUAN A.; SCOTTO, JULIANA; MARMISOLLÉ, WALDEMAR A.; AZZARONI, OMAR

Advanced Materials Interfaces

WILEY-VCH Verlag GmbH & Co

Año: 2022

2196-7350

The biofunctionalization of graphene field-effect transistors (GFETs) through vinylsulfonated-polyethyleneimine nanoscaffold is presented for enhanced biosensing of severe acute respiratory-related coronavirus 2 (SARS-CoV-2) spike protein and human ferritin, two targets of great impor- tance for the rapid diagnostic and monitoring of individuals with COVID-19. The heterobifunctional nanoscaffold enables covalent immobilization of binding proteins and antifouling polymers while the whole architecture is attached to graphene by multivalent π?π interactions. First, to optimize the sensing platform, concanavalin A is employed for glycoprotein detec- tion. Then, monoclonal antibodies specific against SARS-CoV-2 spikeprotein and human ferritin are anchored, yielding biosensors with limit ofdetections of 0.74 and 0.23 nm, and apparent affinity constants (K GFET ) of6.7 and 8.8 nm, respectively. Both biosensing platforms show good speci- ficity, fast time response, and wide dynamic range (0.1?100 nm). Moreover, SARS-CoV-2 spike protein is also detected in spiked nasopharyngeal swab samples. To rigorously validate this biosensing technology, the GFET response is matched with surface plasmon resonance measurements, exhibiting linear correlations (from 2 to 100 ng cm−2) and good agreement in terms of KD values. Finally, the performance of the biosensors fabri- cated through the nanoscaffold strategy is compared with those obtained through the widely employed monopyrene approach, showing enhancedsensitivity.