A nanoporous electrochemical aptamer-based sensors for rapid detection of cardiac troponin I in blood.

Acute myocardial infarction (AMI) is one of the top contributors to global disease mortality. AMI biomarkers, such as cardiac troponin I (cTnI), are often detected with enzyme-linked immunosorbent assay (ELISA) that suffers from several well-known drawbacks such as poor stability and slow and cumbersome operation. Therefore, it is necessary to develop a new analytical technique that can rapidly analyse and detect cTnI for early screening of AMI. In this work, a nanoporous electrochemical aptamer-based (E-AB) sensor for rapid and sensitivite detect of cTnI was designed. Firstly, the aptamer was truncated, and then molecular docking simulation and circular dichroism (CD) were used to screen for aptamers with significant conformational changes when binding to the target, in order to enhance the sensitivity of E-AB sensors. Subsequently, nanoporous electrodes with active area 20 times higher than that of smooth electrodes were fabricated by electrochemical alloying/dealloying, which enabled E-AB sensors to obtain higher signal-to-noise ratios, providing favorable assurance for the detection results. Under optimal conditions, E-AB sensors could specifically detect cTnI in serum and blood with a detection limit of 1 pg/mL. At the same time, the sensor and enzyme-linked immunoassay (ELISA) had identical detection results when measuring target levels from real clinical samples. Furthermore, the sensor exhibited good reproducibility, stability, providing a simple and low-cost method for detecting cTnI, which is expected to help early AMI patients obtain accurate diagnosis.