The co-assembly of spike silica nanoparticles with high affinity to nucleic acid for airborne virus detection

The global pandemic of coronavirus disease 2019 (COVID-19) highlights the shortcomings of the current testing paradigm for viral disease diagnostics. Though the Polymerase Chain Reaction (PCR) technique is currently used for nucleic acid detection in liquid samples, its application in airborne virus has not yet been developed, due to low viral load in the air, lack of efficient capture probe and supporting equipment. Herein, we developed an ultrasensitive biosensing nanoplatform for airborne virus detection. The extraction and concentration of nucleic acid from test samples has been accomplished by novel spike silica nanoparticles (SSNPs)-based nucleic acid capture probe with high spike length to nanoparticle diameter ratio and appropriate surface potential. When integrated with air sampler and Quantitative Real-Time PCR (qPCR) equipment, nucleic acid enrichment can be achieved significantly. Our results demonstrated a successful detection of the virus in the air with the limit of detection (LoD) of 500 copies/L, which greatly surpasses the LoD of 1 × 10⁶ copies/L. This detection method effectively addresses the obstacle posed by the low abundance of pathogens in the environment and could be applied for the detection of pathogens in air or water, aiming to achieve the goal of disease prevention and control prior to its onset.