The successful fabrication of the cTnI detection platform is very meaningful for instant diagnosis of the myocardialinjury and related cardiovascular diseases (CVDs). In this research work, the magnetic nanoparticles and aptamer collaboration with the Cas12a/crRNA are used for the electrochemical detection of cTnI. The aptamer is hybridized with its partially complementary DNA (probe 2, P2) and then is modified on the magnetic nanoparticles. In the presence of cTnI, the cTnI combines with the aptamer and P2 is released. The released P2 is hybridized with the crRNA and the trans-cleavage activity of CRISPR/Cas12a is triggered. Therefore, the methylene blue-modified DNA (probe1, P1) on the surface of the electrode is cleaved, resulting in the decrease of the electrochemical signal. Based on the synergy effect of the high specific target recognition of aptamer, target-specifically triggering trans-cleavage activity of CRISPR/Cas12a, as well as good separation ability of magnetic nanoparticles, the developed electrochemical biosensor enables to detect cTnI with high specificity and sensitivity. The detection limit is low down to 10 pg/mL with a linear range from 100 pg/mL to 50000 pg/mL. The developed sensing platform was successfully applied for the detection of cTnI in human serum. This fabricated CRISPR/Cas12a-based electrochemical biosensor can offer a valuable tool for the diagnosis, prognosis, and treatment of patient with CVDs.Copyright © 2022. Published by Elsevier B.V.