Ultrasensitive electrochemical immunosensor integrated trimetallic PtCuRu alloy and N-rich interpenetrating twin porous carbon for quantitative detection of cTnI

Abstract

As a gold standard biomarker for acute myocardial infarction (AMI), cardiac troponin I (cTnI) plays a crucial role in the prevention and monitoring of this condition. Herein, an efficient sandwich-type electrochemical immunosensor is developed for the quantitative measurement of cTnI utilizing highly active trimetallic PtCuRu as a signal amplification platform and N-rich interpenetrating twin porous carbon (ITPC) decorated with gold nanoparticles (Au NPs/ITPC) as matrix material. The morphologically controlled ZIF-8-derived ITPC, synthesized via a facile and green method, features enlarged surface area and high nitrogen content, enabling effective H2O2 enrichment and Ab1 immobilization, thereby enhancing the stability and sensitivity of the biosensor. In addition, thanks to its open structure and optimized d-orbital coupling features, the meticulously designed flower-like PtCuRu (PtCuRu NF) possess efficient mass and electron transfer ability, favoring amplifying its H2O2 electroreduction activity. These intrinsic advantages of the precisely fabricated electrochemical immunosensor enable outstanding sensitivity, wide dynamic linear range (10 fg mL- 1 to 100ng mL-1) as well as ultralow detection limit (0.58 fg mL- 1) for cTnI. In addition, excellent reproducibility, ideal selectivity and long-term stability were also achieved for the cTnI detection. This work pioneered an innovative precisely designed method for sandwichtype electrochemical immunosensor enabling early, quantitative measurement and prognosis of cTnI.