A graphene FET biosensing platform integrated with Fe₃O₄@SiO₂@Ce-Zr bimetallic MOFs for rapid SARS-CoV-2 detection

A hybrid biosensing platform was developed for ultrasensitive detection of the SARS-CoV-2 nucleocapsid (N) protein by integrating an antibody-engineered magnetic bimetal-organic framework with a graphene field-effect transistor (GFET) readout. In this design, Fe₃O₄@SiO₂@Ce-Zr MOF particles were prepared and functionalized with an anti-SARS-CoV-2 N protein antibody (AntiE₂) to selectively capture the N protein in phosphate-buffered saline (PBS). After magnetic enrichment and washing with PBS, the resulting immune complexes were interfaced with a GFET to convert the biorecognition event into an electrical signal. The device response exhibited a linear relationship over concentrations from 1 ag⋅mL^-1 to 10 ng⋅mL^-1, achieving a limit of detection of 4.08 ag⋅mL^-1. The feasibility of this strategy was further verified in serum matrices, supporting its potential for sensitive detection in complex biological samples.