Micromotor-assisted graphene field-effect transistor for label-free and ultrasensitive detection of SARS-CoV-2 in...

Outbreaks of infectious diseases pose a major challenge to public health and social development, creating an urgent need for rapid, sensitive, and field-deployable diagnostic platforms. We developed a label-free sensing strategy for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by integrating antibody-functionalized Fe₃O₄@TiO₂@MnO₂ magnetic micromotors with a graphene field-effect transistor (GFET). The micromotors exhibited self-propulsion in H₂O₂ solution due to catalytic oxygen generation, which enhanced target capture and enrichment efficiency. After magnetic separation, the collected micromotor-target complexes were directly analyzed by GFET for quantitative detection. Under optimized conditions, the platform showed a wide linear response and achieved an ultralow limit of detection of ag/mL in PBS. The sensing system also maintained reliable analytical performance in complex matrices, with detection limits of 37.5 ag/mL in human serum and 19.1 ag/mL in soil solution. In addition, the platform exhibited excellent reproducibility and favorable reusability. These results demonstrate that the proposed micromotor-assisted GFET platform provides a sensitive and robust approach for SARS-CoV-2 detection and holds considerable promise for on-site determination of infectious pathogens in complex real-sample environments.