Ruthenium oxide electrode integrated with molecularly imprinted polymer for direct electrochemical sensing of a neurotrophic factor protein

Abstract

In the pursuit of precision diagnostics and analytical methodologies, electrochemical devices have emerged as a promising frontier. This article presents the synergy between a molecularly imprinted polymer (MIP) layer and the ruthenium dioxide (RuO₂) electrode as components of an electrochemical sensor designed for direct detection of disease biomarkers. For this purpose, brain-derived neurotrophic factor (BDNF), a potential biomarker for neurodegenerative disorder, was selected as the target analyte. By anchoring a BDNF-selective MIP (BDNF-MIP) layer to RuO₂ electrode functioning as both a substrate transducer and a redox-active internal probe, a direct electrochemical analysis of BDNF was achieved. Following the optimization of the template elution, rebinding time, and BDNF-MIP layer thickness, linear sweep voltammetry (LSV) analysis of the BDNF sensor demonstrated low detection limit, 0.1 ng/mL in buffer and an effective functionality within two linear analytical ranges (0–15 ng/mL and 15–40 ng/mL) in serum. Additionally, exceptional discriminatory selectivity for the target was confirmed in comparison with other neurotrophic factors, as well as other proteins. Importantly, an outstanding reusability of the BDNF sensor during at least 8 rebinding-regeneration cycles was achieved. Thus, the resulting sensing platform offers rapid and precise analysis of biological samples, paving the way for enhanced diagnostics and analytical methodologies across various scientific disciplines.