Abstract
Direct detection of SARS-CoV-2 in biological specimens is often challenging due to the low abundance of viral components and lack of enough sensitivity. Herein, we developed a new type of chemiluminescent functionalized magnetic nanomaterial for sensitive detection of the SARS-CoV-2 antigen. First, HAuCl 4 was reduced by N -(aminobutyl)- N -(ethylisoluminol) (ABEI) in the presence of amino magnetic beads (MB-NH 2 ) to generate ABEI-AuNPs, which were directly assembled on the surface of MB-NH 2 . Then, Co 2+ was modified onto the surface to form MB@ABEI-Au/Co 2+ (MAA/Co 2+ ). MAA/Co 2+ exhibited good chemiluminescence (CL) and magnetic properties. It was also found that it was easy for the antibody to be connected with MAA/Co 2+ . Accordingly, MAA/Co 2+ was used as a sensing interface to construct a label-free immunoassay for rapid detection of the N protein in SARS-CoV-2. The immunoassay showed a linear range from 0.1 pg/mL to 10 ng/mL and a low detection limit of 69 fg/mL, which was superior to previously reported methods for N protein detection. It also demonstrated good selectivity by virtue of magnetic separation, which effectively removed a sample matrix after immunoreactions. It was successfully applied for the detection of the N protein in spiked human serum and saliva samples. Furthermore, the immunoassay was integrated with an automatic CL analyzer with magnetic separation to detect the N protein in patient serums and rehabilitation patient serums with satisfactory results. Thus, the CL immunoassay without a complicated labeling procedure is sensitive, selective, fast, simple, and cost-effective, which may be used to combat the COVID-19 pandemic. Finally, the CL quenching mechanism of the N protein in the immunoassay was also explored.
【초록키워드】 SARS-CoV-2, Saliva, antibody, COVID-19 pandemic, rehabilitation, Antigen, immunoassay, serum, sensitivity, Patient, N protein, SARS-CoV-2 antigen, chemiluminescence, human serum, mechanism, Detection limit, specimen, saliva samples, component, selective, magnetic bead, labeling, virtue, Direct, was used, detect, lack, reported, generate, linear, applied, exhibited, demonstrated, was reduced, the N protein, the immunoassay, the SARS-CoV-2, 【제목키워드】 detection, Rapid, sensitive, the SARS-CoV-2,