A conductive poly(m-aminophenol) interface for α-lipoic acid detection in NELL-1 membranous nephropathy

Abstract

Conductive polymers are crucial for improving the performance of electrochemical sensors due to their tunable electronic properties and functional versatility. Poly(m-aminophenol) (PmAP), a conductive polymer, serves as an electroactive interface for the development of a disposable point-of-care (POC) electrochemical sensor for α-lipoic acid (LA) detection, a potential etiological trigger of neural epidermal growth factor-like 1 protein-associated membranous nephropathy (NELL-1 MN). Synthesized via oxidative polymerization of diphenylamine-cross-linked m-aminophenol, PmAP exhibits a hierarchically porous morphology and intrinsic redox activity, enabling efficient electron transfer. Immobilization onto screen-printed gold electrodes (Au-SPEs) provides a cost-effective and scalable sensing platform. Electrochemical impedance spectroscopy (EIS) reveals that PmAP significantly reduces charge-transfer resistance and enhances electron transfer kinetics. Differential pulse voltammetry (DPV) confirms that LA selectively interacts with PmAP, leading to a concentration-dependent attenuation of oxidation peak current across a 1–300 µM range. The PmAP/Au-SPE sensor achieves a sensitivity of 4.77 µA cm⁻² µM⁻¹ and a detection limit of 430 nM, demonstrating high selectivity with minimal interference from biologically relevant analytes. Additionally, the sensor achieves a recovery rate of 101% ± 6.32% in human serum, validating its clinical applicability. The integration of PmAP as a versatile polymeric interface offers a highly robust, stable, and selective platform for real-time renal function assessment and early-stage NELL-1 MN monitoring.