Sensitive and Selective Electrochemical Determination of Thrombin as a Peptide Biomarker by a Multiwalled Carbon Nanotube (MWCNT)/Aptamer/Molecularly Imprinted Polymer (MIP)-Based Biosensor

Molecularly imprinted polymer (MIP) and DNA aptamers detect targets with high sensitivity and specificity, simulating the structure and function of antibodies and biological receptors. The combination of MIPs and aptamers is being an excellent way to create hybrid alternatives with enhanced attributes and desirable properties. With this motivation, a new method has been developed to produce aptamer/MIP hybrids for protein biomarkers that is simple and reproducible. In addition, multi-walled carbon nanotubes (MWCNTs) were used because of their outstanding chemical/mechanical stability to develop sensitive sensor/biosensors. The MWCNTs/Aptamer/MIP system was characterized using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Furthermore, atomic force microscopy (AFM) was used for morphological characterization. Thrombin was used as a model peptide for this system with a linear response from 5 pg/mL to 150 pg/mL and a detection limit of 1.4 pg/mL. The system was also tested for selectivity, stability, and practical analysis and showed satisfactory results compared to the literature.