Amiloride-modulated phosphorescence turn-off/on method for the detection of abasic site-containing dsRNA based on uridine triphosphate-capped Mn-doped ZnS quantum dots

RNA plays a crucial role in biochemical processes. RNAs with abasic sites (AP-RNA), as one of RNA lesions, will cause serious negative consequences. Efficient and sensitive detection of AP-RNA deserves but does not receive enough attention. Water-soluble uridine triphosphate (UTP)-capped Mn-doped ZnS quantum dots (QDs), which have excellent room-temperature phosphorescence (RTP) properties, were prepared by wet-chemical method. The UTP on the surface of QDs could form a precipitation complex with amiloride (AMI) to quench the RTP. Meanwhile, abasic double-stranded RNA (AP-dsRNA) with a high affinity to AMI could dissociate AMI from the surface of UTP-QDs, resulting in RTP recovery. In this process, a highly sensitive and selective RTP-detection system for AP-dsRNA was constructed with AMI as the modulation factor and UTP-QDs as the luminescence matrix. RTP was turned off and on for the determination of AP-dsRNA, and the interference of background fluorescence and scattered light was effectively avoided during complex formation and aggregation. Steric hindrance of the conformation of AP-dsRNA provided efficient selectivity. The detection limit for AP-dsRNA was 0.86 nM, the relative standard deviation was 2.1%, and the recovery of biological samples with AP-dsRNA addition ranged from 95% to 103% at optimal conditions. The system is expected to provide new methods for environmental monitoring, early disease screening, and evaluation of gene editing efficiency.