MICaFVi: A Novel Magnetic Immuno-Capture Flow Virometry Nano-Based Diagnostic Tool for Detection of Coronaviruses.

COVID-19 has resulted in a pandemic that aggravated the world's healthcare systems, economies, and education, and caused millions of global deaths. Until now, there has been no specific, reliable, and effective treatment to combat the virus and its variants. The current standard tedious PCR-based tests have limitations in terms of sensitivity, specificity, turnaround time, and false negative results. Thus, an alternative, rapid, accurate, and sensitive diagnostic tool that can detect viral particles, without the need for amplification or viral replication, is central to infectious disease surveillance. Here, we report MICaFVi (Magnetic Immuno-Capture Flow Virometry), a novel precise nano-biosensor diagnostic assay for coronavirus detection which combines the MNP-based immuno-capture of viruses for enrichment followed by flow-virometry analysis, enabling the sensitive detection of viral particles and pseudoviruses. As proof of concept, virus-mimicking spike-protein-coated silica particles (VM-SPs) were captured using anti-spike-antibody-conjugated MNPs (AS-MNPs) followed by detection using flow cytometry. Our results showed that MICaFVi can successfully detect viral MERS-CoV/SARS-CoV-2-mimicking particles as well as MERS-CoV pseudoviral particles (MERSpp) with high specificity and sensitivity, where a limit of detection (LOD) of 3.9 µg/mL (20 pmol/mL) was achieved. The proposed method has great potential for designing practical, specific, and point-of-care testing for rapid and sensitive diagnoses of coronavirus and other infectious diseases.

Unleashing immuno-mass spectrometry superpowers to detect SARS-CoV-2.

In this article of EBioMedicine, Santosh Renuse and colleagues1 show the relevance of combining immunoaffinity capture with targeted mass spectrometry measurement to detect SARS-CoV-2 nucleocapsid proteins in nasopharyngeal swab samples. The COVID-19 pandemic has confirmed the need to improve the toolbox available to diagnose respiratory infections. Rapid, reliable, and highly specific detection is essential if we are to mount immediate preventive and therapeutic responses. This report stands out from previous studies as it implements immunocapture along with robust validation for a large cohort of subjects. The results presented show that mass spectrometry is definitively at a crossroads for large-scale clinical applications.