A dual-mode sensor based on intramolecular catalytic hairpin assembly strategy (intra-CHA) is proposed for Survivin mRNA detection. Intra-CHA, a triplex complex of tetraferrocene-labeled H1/H2, shortens H1-H2 distance and increases their local concentrations, accelerating reaction by 2.8-fold vs. free-CHA. Ruthenium-based covalent organic frameworks (RuCOFs) with Ru(dcbpy) 3 2+ as luminophore has dual fluorescence-electrochemiluminescence (FL-ECL) properties. EDTA-incorporated RuCOFs@EDTA expands active sites, enhancing ECL efficiency 8-fold. Intra-CHA system is covalently conjugated to RuCOFs@EDTA through amide bond linkages. Target mRNA-triggered strand displacement reactions induce structural reconfiguration of the intra-CHA probes, resulting in controlled spatial segregation of tetraferrocene from the RuCOFs@EDTA interface. This results in the recovery of FL and ECL signals, enabling rapid and highly sensitive detection of Survivin mRNA. Experimental results show that the detection limits reach 0.04 fM (in the FL mode) and 0.009 fM (in the ECL mode) respectively, with excellent selectivity, stability, and reproducibility. The system has been successfully applied to detect Survivin mRNA in actual serum samples, providing a novel strategy for Survivin mRNA detection and paving the way for developing future diagnostic strategies for early cancer screening. Graphical
Rapid and sensitive nucleic acid detection is vital in disease diagnosis and therapeutic assessment. Herein, we propose a co-freezing localized CRISPR-Cas12a (CL-Cas12a) strategy for sensitive nucleic acid detection. The CL-Cas12a was obtained through a 15-minute co-freezing process, allowing the Cas12a/crRNA complex and hairpin reporter confined on the AuNPs surface with high load efficiency, for rapid sensing of nucleic acid with superior performance to other localized Cas12a strategies. This CL-Cas12a based platform could quantitatively detect targets down to 98 aM in 30 min with excellent specificity. Furthermore, the CL-Cas12a successful applied to detect human papillomavirus infection and human lung cancer-associated single-nucleotide mutations. We also achieved powerful signal amplification for imaging Survivin mRNA in living cells. These findings highlight the potential of CL-Cas12a as an effective tool for nucleic acid diagnostics and disease monitoring.Graphical abstract
危险品化学品经营许可证（带存储）