Ultrasensitive detection of tumor marker CA15–3 using a CRISPR/Cas12a-assisted CdTe QDs@ZIF-8 dual-emission fluorescence sensor

CA15–3 is a vital biomarker for monitoring and evaluating treatment efficacy in breast cancer patients, especially those with advanced-stage disease. Conventional immunoassays face limitations, including high cost, limited sensitivity, and dependence on potentially error-prone single-fluorescence signal outputs. To address these challenges, we designed a dual-signal-emitting sensor based on CdTe quantum dots@ZIF-8 nanomaterials, incorporating both the CRISPR/Cas12a system and catalytic hairpin assembly (CHA) technology. The binding of CA15–3 to its specific aptamer inhibits the CHA cascade reaction, thereby preventing the generation of double-stranded DNA activators necessary to initiate Cas12a-mediated trans-cleavage activity. As a result, FAM-ssDNA is extensively adsorbed onto the CdTe QDs@ZIF-8 surface, where efficient electron transfer effectively quenches its fluorescence. The incorporation of the aptamer facilitates dual-signal amplification through both the CHA and CRISPR/Cas12a systems, achieving a detection limit of 0.131 U/mL. This dual-signal output mechanism provides the system with an internal reference function, thereby significantly improving the reliability of the results. Overall, this work establishes a novel tumor biomarker detection platform that combines high sensitivity with excellent robustness.