This paper presents a novel strategy for the real-time, selective, and low-cost detection of trace-level SARS-CoV-2 spike protein in cold-chain foods. The method utilizes a modified interdigitated microelectrode chip, dielectrophoresis enrichment, and interfacial capacitance sensing to achieve a limit of detection as low as 2.29 × 10⁻¹⁰ ng/mL within 20 seconds. The method exhibits a wide linear range (10⁻⁵-10⁻¹ ng/mL) and high selectivity (234:1), while the cost per test is approximately $1. This technology offers a promising solution for large-scale screening in cold-chain food quarantine.
