Dual-Mode Electrochemical Biosensor Based on Gold Nanoparticles/Two-Dimensional MoWS₂/Graphene Oxide Composite for Detection of Glycated Albumin and Glucose toward Advancing Diabetes Diagnosis

Diabetes, a widespread chronic disease, is characterized by dysregulated blood glucose levels, necessitating early diagnosis for effective management and complication prevention. To address the need for a more comprehensive diagnostic approach, we present a novel dual-mode electrochemical biosensor capable of simultaneously detecting two clinical biomarkers─glycated albumin (GA) and glucose─a combination not previously reported on a single platform. While glucose reflects immediate glycemic status, GA provides insight into short- to intermediate-term control; thus, their concurrent detection enables a more holistic glycemic assessment, enhancing diagnostic accuracy. This simultaneous biosensor demonstrates competitive immunoassay and enzymatic detection. The biosensor integrates polyethylenimine-capped gold nanoparticles, graphene oxide, and two-dimensional bimetallic molybdenum tungsten disulfide onto two working area screen-printed carbon electrodes, enhancing sensitivity and performance. For glucose detection, glucose oxidase and ferrocene monocarboxylic acid function as the enzyme catalyst and redox mediator, while a competitive immunosensor employing methylene blue as a redox signal selectively identifies GA. Differential pulse voltammetry facilitates simultaneous high-precision biomarker quantification. Validated in a 50-fold diluted human serum, the biosensor exhibited remarkable detection ranges of 500-25,000 pg mL^-1 for GA and 0.5-8.0 mM for glucose, achieving detection limits of 320 pg mL^-1 and 0.15 mM, respectively. By integrating GA and fasting plasma glucose assessments, this innovative biosensor design enhances diagnostic accuracy, addressing the limitations of individual methods and paving the way for a robust diabetes monitoring system that transforms diagnostic strategies for improved patient outcomes.