A novel electrochemical sensor based MXene/OKB composite for the simultaneous detection of Hcy and ONOO^- in...

It is essential to maintain redox homeostasis between reactive nitrogen species (RNS) and reactive sulfur species (RSS) for normal physiological function. Peroxynitrite (ONOO^-) and homocysteine (Hcy) are the representative RNS and RSS, and dysregulation of their concentrations will drive various oxidative stress-related diseases. Given that such pathologies typically involve the dysregulation of multiple species, the development of highly sensitive sensors for simultaneous detection is of great significance for mitigating associated health risks. Herein, we constructed a novel electrochemical sensor based on the MXene/OKB composite. This composite enhanced the electrocatalytic activity toward Hcy and ONOO^- oxidation, enabling a well-defined peak separation of 0.368 V. As a result, the sensor exhibited exceptional performance, featuring wide linear ranges (Hcy: 0.983 - 210 μM, ONOO^-: 0.104 - 83 μM) and low detection limits (Hcy: 0.32 μM; ONOO^-: 0.034 μM), alongside good reproducibility and stability. Its practical applicability was successfully validated through the simultaneous detection of both species in biological samples, achieving satisfactory recoveries. Taken together, the MXene/OKB composite emerges as a promising nanomaterial, and the developed platform proves to be a reliable tool for detecting redox homeostasis-related biomarkers. This work holds considerable promise for advancing studies of oxidative stress-related pathologies and early diagnosis.