Development and evaluation of a conductive titanium carbide/thiolated pectin hydrogel-based sensing system for...

Biosensors play an important role in disease detection, drug monitoring, food safety assurance, and chemical hazard identification. In this study, we developed a conductive hydrogel-based sensing system using thiolated citrus pectin (TP) polymer and two-dimensional (2D) titanium carbide (MXene) nanosheets. The TP polymer was crosslinked with disodium hydrogen phosphate (Na₂HPO₄) at concentrations of 0.5, 1, and 1.5 M to form hydrogels containing disulfide bonds (-S-S-). The hydrogel containing 1 mg/mL MXene and crosslinked with 1 M Na₂HPO₄ reached gelation within 27 min. In addition, MXene incorporation increased the compressive modulus to 3.4 ± 0.1 kPa and enhanced the electrical conductivity to 0.73 ± 0.03 S/m. We then applied the MXene/TP hydrogels as biosensors for detecting the antioxidant glutathione (GSH). GSH reduced disulfide bonds within the hydrogel network and induced changes in the electrochemical signals. As a result, the hydrogel enabled GSH detection over a micromolar concentration range from 0 to 15 μM. Moreover, we integrated the hydrogel with a microfluidic device to establish a dynamic flow-based sensing platform. This platform produced distinguishable electrochemical responses at different GSH concentrations and supported continuous GSH monitoring. Overall, this conductive hydrogel-based sensing system provides an effective strategy for GSH detection and shows strong potential as a preliminary platform for assessing GSH-related neurodegenerative conditions.