Ultrasensitive point-of-care multiplex diagnosis for influenza virus based robust quantum dot microsphere-lateral flow immunoassay.

Influenza A virus (IAV) and influenza B virus (IBV) with similar symptoms of infection caused a serious disease burden and economic losses in annual epidemic season, so it is important to quickly and accurately detect and distinguish between IAV and IBV during influenza season. Herein, the quantum dot microspheres (QDMS) were synthesized and applied to lateral flow immunoassays (LFIA), and a point-of-care (POC) biosensor that can discriminately and simultaneously diagnose IAV and IBV within 10 min was established. A double-sandwich QDMS nanotags was synthesized by immobilizing hydrophobic quantum dots (QDs) with chemical bonding method on a silica sphere template with an outer silica shell protection showed excellent stability and high fluorescence. The highly sensitive quantitative detection is achieved with the tailored hand-hold detector. The limit of detection (LOD) of the LFIA based QDMS for the simultaneous detection of IAV and IBV were 0.080 ng/mL and 0.096 ng/mL, respectively. The QDMS-LFIA system has excellent specificity and stability for quantitative detection, especially showing good accuracy for clinical samples. Furthermore, the visualization sensitivity of the low-cost biosensor was improved by nearly an order of magnitude than gold nanoparticles (AuNP)-LFIA within shorter detection time. Given the excellent performance, our proposed QDMS-LFIA biosensor can potentially be applied to the POC sensitive discriminate and simultaneous detection of IAV and IBV in epidemic season.