Development of a Reagentless Molecularly Imprinted Polymer-Based Electrochemical Biosensor for Rapid Troponin I Detection in Biofluids

Cardiovascular diseases (CVDs) remain the leading cause of death worldwide, highlighting the urgent need for efficient diagnostic methods. Troponin I (TnI) serves as a critical biomarker for myocardial infarction, necessitating tools for its rapid and accurate detection. This study presents a reagentless molecularly imprinted polymer (MIP)-based electrochemical biosensor designed for single-step TnI detection in untreated biofluids. The biosensor utilizes a MIP layer formed via the electropolymerization of orthophenylene diamine on lab produced screen printed gold electrodes. The polymerization conditions, including the monomer-to-template ratio, and the type of washing solution, were systematically optimized to maximize the sensitivity and performance of the MIP. Characterization techniques, such as atomic force microscopy (AFM) and Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy confirmed the successful formation of the MIP layer and the effective removal of the template. Electrochemical analyses, including electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV), demonstrated the biosensor’s linear response to TnI concentrations between 10 pg/mL and 100 pg/mL, with a detection limit of 2.62 pg/mL. This sensitivity is on par with enzyme-linked immunosorbent assays (ELISAs) while offering the added benefits of a reagent-free and rapid detection process. The biosensor exhibited minimal cross-reactivity with other cardiac biomarkers, such as troponin T, prothrombin, and thrombin, ensuring reliable performance in complex biological samples. Validation with untreated human serum samples showed recovery rates between 95% and 105%, demonstrating its accuracy and potential for clinical applications. Importantly, the sensor provided stable readings within 5 minutes, making it suitable for emergency diagnostic use. This work underscores the potential of MIP-based electrochemical sensors for point-of-care diagnostics, combining cost-effectiveness, user-friendliness, and high specificity. Future efforts will focus on miniaturizing the sensor for portable use and expanding the platform to detect other clinically relevant biomarkers. By providing a reagentless and efficient solution for TnI detection, this study paves the way for the broader adoption of electrochemical biosensors in the early diagnosis of myocardial infarction, ultimately improving patient outcomes. Keywords: Troponin I, Molecularly Imprinted Polymer, Electrochemical Biosensor, Reagentless Detection, Cardiovascular Diagnostics, Point-of-Care Testing