REAGENT-FREE ELECTROCHEMICAL BIOSENSOR UTILIZING MOLECULARLY IMPRINTED POLYMERS FOR SINGLE-STEP DETECTION OF TROPONIN I IN BIOLOGICAL SAMPLES

Cardiovascular diseases (CVDs) are a leading cause of mortality worldwide, making the rapid and accurate detection of biomarkers like troponin I (TnI) crucial for early diagnosis of myocardial infarction (MI).This study introduces a novel reagentless molecularly imprinted polymer (MIP)-based electrochemical biosensor for single-step detection of TnI in biofluids.The biosensor integrates Prussian blue (PB) as an embedded redox probe on a lab-designed gold working electrode (GWE) with a signal-off MIP assay.Electropolymerization of orthophenylene diamine (O-PD) in the presence of TnI creates a MIP layer with high-affinity binding sites specific to TnI.Pre-treatment of gold electrodes enhances surface roughness, improving polymer adhesion and sensor sensitivity.Optimizing the monomer-to-template ratio and polymerization conditions further refines the MIP's specificity.Characterization of the MIP layer via scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) confirms successful polymer formation and template removal.Cyclic voltammetry (CV), atomic force microscopy (AFM), and Raman spectroscopy fully characterize the preparation steps.Differential pulse voltammetry (DPV) was employed to assess the biosensor's performance.The biosensor exhibited a linear response to TnI concentrations ranging from 10 pg/mL to 100 pg/mL in both serum and plasma, with a detection limit of 3.55 and 1.77 pg/mL in serum and plasma respectively.This sensitivity is comparable to conventional enzyme-linked immunosorbent assays (ELISAs) but offers the advantage of a reagentless and more rapid detection process.Selectivity tests demonstrated minimal interference from other cardiac biomarkers, such as thrombin, prothrombin, and Troponin T, ensuring the biosensor's reliability in complex biological matrices.The biosensor's applicability was validated using human serum samples spiked with known concentrations of TnI.The recovery rates ranged from 98% to 102%, demonstrating excellent accuracy and potential for clinical application.The sensor achieved stable readings within 5 minutes, crucial for emergency diagnostic settings.This study presents a significant advancement in the development of electrochemical biosensors for cardiac biomarker detection.The reagentless MIP-based electrochemical biosensor offers a promising tool for the early diagnosis of myocardial infarction, potentially improving patient outcomes through timely and accurate detection of TnI in biofluids.The methodology described can be adapted for the detection of a wide range of biomarkers, paving the way for versatile and efficient point-of-care diagnostic devices.