Noncompetitive Fluorescence Polarization Aptamer Assay for Detecting SARS-CoV‑2 Variants

Although the SARS-CoV-2 pandemic has subsided with the widespread rollout of vaccines, emerging variants continue to pose significant public health challenges. While current diagnostic technologies can sensitively detect specific variants, there is an increasing need for broad-spectrum detection methods that are less affected by viral mutations. In particular, the development of diagnostic techniques that are not only broadly applicable but also rapid and cost-effective is highly desirable for large-scale screening and long-term surveillance. In this study, the applicability of a noncompetitive fluorescence polarization aptamer assay (NC-FPAA) was evaluated for detecting SARS-CoV-2, including both the wild-type strain and various variants. Two fluorescently labeled aptamers, a 77-mer (K1) and a 51-mer (M40), previously reported to have broad affinity for spike proteins of different SARS-CoV-2 variants, were used as probes. Detection experiments were conducted using eight SARS-CoV-2 variants, and specificity was further assessed using influenza viruses. The results demonstrate that NC-FPAA has the potential to serve as a diagnostic tool for the rapid, simple, and low-cost detection of multiple SARS-CoV-2 variants, thereby supporting broad and effective viral surveillance.