Evaluation of molecular imprinted polymerized methylene blue/aptamer as a novel hybrid receptor for Cardiac Troponin I (cTnI) detection at glassy carbon electrodes modified with new biosynthesized ZnONPs

In this research, a novel, rapid, and non-immune electrochemical method was used to detect cardiac troponin I (cTnI) using a double recognition approach. Amine terminus cTnI aptamers immobilized on COOH-ZnO nanoparticles (COOH-ZnONPs) modified GCE surface were applied to capture cTnI for imprinting recognition. The COOH-ZnONPs were synthesized in a biological manner. Then, the methylene blue (MB) monomers were electro-polymerized around the cTnI-aptamer complexes. Following the removal of cTnI, cavities were constructed and converted to a new aptamer and molecular imprinted polymer (MIP) hybrid receptor (aptamer/MIP/ZnONPs). FT-IR spectra, SEM images, XRD patterns, and electrochemical impedance spectroscopy (EIS) were used to evaluate different steps. With respect to differential pulse voltammetry and the anodic peak of polymethylene blue (PMB), cTnI was found to be in a linear range from 0.50-3.3 x 10(5) pM (1.25 x 10(-5)-8.25 mu g/mL) with a detection limit of 1.04 pM (2.61 x 10(-5)mu g/ml) and quantification limit of 1.16 pM (2.90 x 10(-5)mu g/mL). The selective determination of cTnI by the proposed aptamer-MIP/ZnONPs sensor was investigated in the presence of cardiac troponin T (cTnT), C-reactive protein (CRP), myoglobin and human serum albumin (HSA). The recovery of the electrode response to cTnI (5.00 x 10(3) pM) in a solution containing the proteins, as mentioned above (5.00 x 10(3) pM) was about 91.2% (RSD = 5.37%) with respect to cTnI alone.