Express and sensitive detection of multiple miRNAs via DNA cascade reactors functionalized photonic crystal array

Array based detection techniques with fluorescence signal reading is a powerful tool for multiple targets analysis. However, when applied fluorescence array for microRNA detection, time-consuming multi-steps surface signal amplification is usually required due to the low abundance of microRNA in total RNA expressions, which impairs detection efficiency and limits its application in point of care test (POCT) manner. Herein, DNA cascade reactors (DCRs) functionalized photonic crystal (PC) array was fabricated for express and sensitive detections of miRNA-21 and miRNA-155. DCRs were assembled by interval conjugation of self-quenched hairpin DNA probes to single strand DNA nanowire synthesized by rolling circle amplification, which generated cascade DNA hybridization reactions in response to target miRNA with instant fluorescence recovery signal. PC array patterns with multi-structure colors further amplified fluorescence with their respective photonic bandgaps (PBGs) matching with the emission peaks of fluorescence molecules labelled on DCRs. The as-prepared DCRs functionalized PC array demonstrated express and sensitive simultaneous detections of miRNA-21 and miRNA-155 with hundreds fM detection limits only in 15 min, and was successfully applied in fast quantifications of low abundance miRNAs from cell lysates and spiked miRNAs from human serum, which would hold great potential for disease diagnosis and therapeutic effect monitoring with a POCT manner.