Lanthanide Metal-Organic Frameworks Enable Target-Triggered CRISPR-Cas12a Activator Release for Ultrasensitive Non-nucleic Acid Biomarker Detection.

Rapid, ultrasensitive detection of cardiac troponin I (cTnI) is critical for the early diagnosis of acute myocardial infarction (AMI). However, CRISPR-Cas systems, despite their unparalleled nucleic acid detection performance, face inherent bottlenecks in protein sensing, including inefficient signal transduction, high background noise, and insufficient anti-interference capability in complex biological matrices. Herein, we report a modular fluorescence signal transduction platform integrating aptamer-functionalized magnetic beads, lanthanide metal-organic frameworks (Ln-MOFs) with high nucleic acid affinity, and CRISPR-Cas12a-mediated collateral cleavage amplification for sensitive cTnI detection. Target cTnI binding to magnetic bead-immobilized aptamers drives the formation of sandwich complexes with CRISPR activator DNA (act)-functionalized Ln-MOFs, triggering phosphate-mediated release of act. The liberated act initiates robust Cas12a trans-cleavage activity, generating an amplified fluorescence readout. This platform achieves a limit of detection (LOD) of 0.1 pg mL-1 in serum samples, with excellent specificity against off-target interfering proteins. Validation in 28 clinical serum samples demonstrates near-perfect agreement with standard clinical ELISA measurements and yields an area under the curve (AUC) of 0.995, confirming its clinical diagnostic accuracy. Furthermore, the modular design enables facile reconfiguration for diverse protein biomarkers via aptamer substitution, providing a universal strategy to expand CRISPR-Cas systems toward non-nucleic acid target detection.