A hierarchical chitosan-intercalated montmorillonite/carboxylated MWCNTs composites for highly-Performance non-invasive glucose sensing via salivary analysis

Abstract Accurate and continuous glucose monitoring is crucial for managing diabetes, especially through non-invasive approaches. High-performance biosensors can be achieved through the design of innovative device architectures and the application of surface-engineered functional materials. Herein, we report a novel electrochemical sensor constructed from a three-dimensional porous composite of chitosan-intercalated montmorillonite (CS-MMT) and carboxylated multi-walled carbon nanotubes (MWCNTs-COOH), enabling ultrasensitive detection of salivary glucose. The hybrid architecture integrates MMT's cation exchange capability and superior specific surface area, the biocompatibility and film-forming properties of chitosan, and the exceptional conductivity of MWCNTs-COOH. The resulting sensor exhibits a broad linear range (0.001-5.78 mM), low detection limit (1.09 μM), and high sensitivity (3.89 μA mM⁻¹ cm⁻²) under operation at a potential of -0.40 V vs. SCE. Superior selectivity, reproducibility, and operational stability were also demonstrated. The sensor's feasibility for real-time, non-intrusive glucose sensing is validated by glucose detection in saliva under fasting and postprandial conditions. This study outlines a prospective strategy for wearable biosensing devices in personalized diabetes management.