CRISPR/Cas13a-Enhanced Porous Hydrogel Encapsulated Photonic Barcodes for Multiplexed Detection of Virus.

In this study, we present an ultrasensitive and specific multiplexed detection method for SARS-CoV-2 and influenza (Flu) utilizing CRISPR/Cas13a technology combined with a hydrogel-encapsulated photonic crystal (PhC) barcode integrated with hybridization chain reaction (HCR). The barcodes, characterized by core-shell structures, are fabricated through partial replication of periodically ordered hexagonally close-packed silicon dioxide beads. Consequently, the opal hydrogel shell of these barcodes features abundant interconnected pores that provide a substantial surface area for probe immobilization. Furthermore, the inherent structural colors remain stable during detection events due to the robust mechanical strength of the barcode cores. This integration of CRISPR/Cas13a and HCR leverages both the highly specific RNA recognition capabilities and trans-cleavage activity of Cas13a while employing HCR to enhance sensitivity. Upon encountering target RNA, Cas13a cleaves a hairpin probe, thereby initiating subsequent HCR amplification for enhanced detection sensitivity. Our method demonstrates high accuracy and sensitivity in multiplexed detection of SARS-CoV-2, Flu A and Flu B RNA with a limit-of-detection as low as 200 aM. Importantly, this assay also exhibits acceptable accuracy in repeated clinical sample testing. Thus, our platform represents a promising strategy for highly sensitive multiplexed virus detection in clinical.