Upconversion Luminescence Sandwich Assay For Detection of Influenza H7 Subtype

With large anti-Stokes shifts and background-free signals, upconversion luminescent (UCL) screening assays have been a promising method to reduce the transmission of influenza epidemic, which can critically alleviate the disease burden and extra annual deaths. In this work, a luminescent resonance energy transfer sandwich assay is developed, which utilizes core-shell upconversion nanoparticles and gold nanoparticles as the donor and acceptor, respectively. The influenza H7 gene of H7N9 virus is used as the target for optimization of the assay. Importantly, the hybridization time of the assay is ≈40 min and the specificity test indicates the probes are specific toward the H7 target. The limit of detection of the system is ≈134 × 10^-12 m (≈3.22 × 10¹⁰ molecules). Moreover, the assay is tested with the use of polymerase chain reaction validated samples from human isolates. The results are promising for implanting future on-site rapid influenza screening application.