Fast responsive crystalline colloidal array photonic crystal glucose sensors.

Area of Science:

• Materials Science
• Biomedical Engineering
• Optics

Background:

• Existing photonic crystal glucose sensors often require chelating agents.
• Diabetes mellitus necessitates continuous glucose monitoring for effective management.
• Contact lenses offer a non-invasive platform for ocular diagnostics.

Purpose of the Study:

• To develop novel photonic crystal polymerized crystalline colloidal array (PCCA) glucose sensing materials.
• To enhance the response kinetics of PCCA glucose sensors for practical applications.
• To design PCCA materials for use in glucose-sensing contact lenses for individuals with diabetes mellitus.

Main Methods:

• Fabrication of hydrogels embedded with monodisperse polystyrene colloids for Bragg diffraction.
• Tuning hydrogel elasticity and hydrophilic-hydrophobic balance via copolymerization (n-hexylacrylate).
• Characterization of sensor response kinetics and sensitivity to glucose concentrations in artificial tear fluid.

Main Results:

• Developed PCCA materials that operate without Na+ chelating agents.
• Achieved significantly faster response kinetics, with full response within 90 seconds to 5 mM glucose and 300 seconds to 0.15 mM glucose.
• Demonstrated sensor responsiveness to physiological glucose concentrations in artificial tear fluid, with unusual temperature-dependent kinetics linked to glucose mutarotation.

Conclusions:

• The new PCCA glucose sensing materials are effective and do not require chelating agents.
• Optimized hydrogel composition leads to rapid response kinetics suitable for continuous glucose monitoring.
• These materials show promise for developing non-invasive, glucose-sensing contact lenses for diabetes management.