Dual-Modular Aptasensor for Detection of Cardiac Troponin I Based on Mesoporous Silica Films by Electrochemiluminescence/Electrochemical Impedance Spectroscopy.

A simple, dual-modular aptasensor for accurate determination of cardiac troponin I (cTnI), a sensitive biomarker of acute myocardial infarction, is reported. It has the parallel output of electrochemiluminescence (ECL) and electrochemical impedance spectroscopy (EIS) based on target-gated transportation of signal probes (luminol/H2O2 or Fe(CN)63-/4-). The sensing capacity is originated from the amino-functionalized mouth margin of the nanochannels in a vertically oriented mesoporous silica film, which was in situ-grown on indium tin oxide-coated glass. With the linkage of glutaraldehyde to couple the aptamer as a trapper, it brings in the high specific target-gated response toward cTnI as decreased ECL or increased EIS. The concentration of cTnI is measurable by the ECL response within a wide linear range from 0.05 pg mL-1 to 10 ng mL-1, as well as the EIS response for a linear range between 0.05 pg mL-1 and 1 ng mL-1. Significantly, the self-verification of these two data from ECL and EIS validated each other with a satisfactory linear correlation (R2 = 0.999), thereby realizing the more reliable and accurate quantification to avoid false results. The designed strategy is an effective method for detection of cTnI, which is of great potential to apply in clinical detection.