Ultra-Fast Photonic Digital Polymerase Chain Reaction based on N-Heterocyclic Carbene Self-Assembled Monolayer

A molecular diagnosis of the respiratory syncytial virus (RSV) without bulky and expensive instrumentation is of great importance for the early detection and prevention in a fast-spreading pandemic. However, the current representative diagnostic methods have the limitation of being time-consuming, cost, the processing time for polymerase chain reaction (PCR), and inaccurate for lateral flow assay (LFA), representatively. Herein, an integrated photonic digital PCR (dPCR) is developed with high-velocity photonic scanner for in situ fluorescence detection by introducing the N-heterocyclic carbene self-assembled monolayer-based Au film to prevent the quenching effect. The on-site rapid molecular diagnostic platform shows the driving of 40 cycles in under 8 min and fluorescence scanning in under 7 min, resulting in a total analysis time within 15 min. In particular, the technology clearly demonstrates the classification of SARS-CoV-2 patients and healthy controls (99% in sensitivity, 98.6% in specificity, and 96.4% in accuracy with RdRp gene), comparing with standard RT-qPCR. This platform can be utilized for prompt point-of-care molecular diagnostics in early diagnosis and large-scale prevention of next pandemic spreading for upcoming infectious diseases and for the distinction diagnosis with other RSV.