The integration of DNA hydrogel with electrochemiluminescence (ECL) technology represents a synergistic enhancement through molecular-level precision design and nanoscale coordination. This strategic integration confers biosensors novel functionalities including intelligent responsiveness and environmental adaptability. In this study, a cascaded hybridization chain reaction (HCR) and CRISPR/Cas12a-integrated DNA hydrogel paper chip was engineered for ultrasensitive microRNA 622 (miRNA 622) detection. Target miRNA 622 triggered HCR amplification via hairpin DNA assembly, while Cas12a recognized protospacer adjacent motif (PAM) sequences within the HCR-generated double-stranded products to activate its trans-cleavage ability. The DNA hydrogel was constructed through copolymerization of acrylamide-modified DNA single strands (SA and SB) with Ru (II) complex-functionalized linker DNA. Activated Cas12a cleaved single-stranded DNA within the DNA hydrogel network, thereby releasing Ru (II) complexes. AuPd nanoparticles (AuPd NPs) served as the co-reactant accelerator, amplifying the cathodic ECL signals of the liberated Ru (II) complexes. The developed platform demonstrated a dynamic detection range from 0.001 to 500 pM with a detection limit of 0.33 fM, establishing a groundbreaking approach for detecting miRNA 622 in clinical diagnostics.
