High-Linearity Hydrogel-Based Capacitive Sensor Based on Con A-Sugar Affinity and Low-Melting-Point Metal

Area of Science:

• Biomedical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Continuous glucose monitoring (CGM) is crucial for diabetes management.
• Affinity glucose sensors offer specificity and stability but face linearity and hydrogel attachment challenges.
• Concanavalin A (Con A) exhibits high specificity to glucose, improving sensor performance.

Purpose of the Study:

• To develop a capacitive glucose sensor with enhanced linearity and a wide detection range.
• To address limitations of existing affinity glucose sensors, particularly in linearity and hydrogel stability.
• To create a reliable and biocompatible sensor for continuous blood glucose monitoring.

Main Methods:

• Fabrication of a capacitive glucose sensor using a glucose-responsive DexG-Con A hydrogel.
• Integration of the hydrogel with a serpentine coplanar electrode made from a low-melting-point metal.
• Characterization of sensor performance, including linearity, sensitivity, and stability across various glucose concentrations.

Main Results:

• The sensor demonstrated high linearity (R² = 0.94) in the 0-20 mM glucose range with a sensitivity of 33.3 pF mM⁻¹.
• Good linearity (R² = 0.84) was maintained even in a wider 0-30 mM glucose concentration range.
• The sensor exhibited excellent resistance to interference from small molecules, good reversibility, and long-term stability.

Conclusions:

• The developed capacitive glucose sensor offers high linearity, a wide detection range, and robust stability.
• The DexG-Con A hydrogel and serpentine electrode design overcome key limitations of previous affinity glucose sensors.
• This low-cost, sensitive, and biocompatible sensor shows significant potential for continuous blood glucose monitoring applications.