Sensitive detection of respiratory syncytial virus based on a dual signal amplified plasmonic enzyme-linked immunosorbent assay

- Signal amplification was achieved by integrating the high loading capacity of MBs with the stimulation effect of Zn2+.
- The reverse plasmonic ELISA utilizing enzyme to disperse the aggregates could reduce the risk of false positive signals.
- The amplified plasmonic immunoassay can be easily adapted for the detection of other pathogens.

The timely detection of infectious pathogen is critical in clinical early diagnosis and treatment of infectious diseases. Plasmonic enzyme-linked immunosorbent assay (ELISA), by means of enzyme-mediated growth or aggregation of AuNPs, has received considerable attention because it allows a naked-eye detection of target in very low numbers. In this work, a dual-signal amplified plasmonic ELISA combined the high loading capacity of magnetic beads with the establishing stimulation effect of zinc ion has been developed to detect RSV as a model pathogen based on alkaline phosphatase-triggered dispersion of aggregated AuNPs. In ideal conditions, the proposed immunoassay can conveniently distinguish the concentration of RSV in a range of 0.1-30 pg/mL. In addition, the limit of detection of RSV of this immunoassay exceeds that of conventional ELISA by about 50 times. The high sensitivity makes this approach a good alternative to existing colorimetric immunoassays for pathogen detection.

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