An Ultrasensitive Virus ELISA Based on a magnetic Mesoporous Silica Nanoprobe

Detection of infectious viruses relies on quantitative polymerase chain reaction (qPCR). However, qPCR requires costly equipment, a clean operating environment and experienced technicians, limiting its wide applicability. On the other hand, enzyme-linked immunosorbent assay (ELISA) is widely used in biological laboratories due to its relatively high sensitivity and ease of operation. However, ELISA-based detection of the virus is hampered because it is lower sensitive than qPCR. Herein, a nanoprobe ELISA (NP-ELISA) based on a mesoporous silica nanoprobe, which is constructed by first being loaded with peroxidase and further coated with positively charged polymer polyethyleneimine, and finally functionalized with antivirus antibodies, is designed. Results show that each NP probe is encapsulating 170 peroxidase molecules and presents 200 antibody molecules on the surface. The limit of detection (LOD) of NP-ELISA (LOD = 1450 PFU mL⁻¹) for the detection of real virus samples is tenfold sensitive than that of standard ELISA (LOD = 14, 414 PFU mL⁻¹) and the assay time for NP-ELISA is reduced by 1 h as compared with standard one. Therefore, the NP-ELISA provides a rapid and sensitive immunoassay platform that can readily be implemented for biological laboratory research as well as for on-site clinical diagnostics.