Composite Dynamic Hydrogels Constructed on Boronic Ester Cross-Links with NIR-Enhanced Diffusivity.

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Chemistry

Background:

• Dynamic hydrogels offer potential for on-demand drug delivery but suffer from inefficient bulk response.
• Achieving uniform and rapid thermoresponsiveness throughout the hydrogel volume is a key challenge.

Purpose of the Study:

• To engineer a graphene oxide-filled composite hydrogel with enhanced thermoresponsiveness for controlled drug delivery.
• To investigate the effect of graphene oxide concentration and cross-linker length on hydrogel properties and drug diffusion.

Main Methods:

• Fabrication of a composite hydrogel using hyperbranched polyglycidol (HbPGL) and poly(acrylamide-ran-2-acrylamidephenylboronic acid) with embedded graphene oxide (GO).
• Evaluation of near-infrared (NIR) photothermal response, including temperature changes and response times at varying GO concentrations.
• Assessment of network diffusivity and drug diffusion (niacin) using diffusion ordered NMR spectroscopy, correlating with cross-linker length.

Main Results:

• The composite hydrogel exhibited rapid bulk heating upon NIR irradiation, with temperature increasing from 36.6 to 41 °C in 29 seconds at 13.2 mg/mL GO.
• Drug diffusion (niacin) significantly increased with temperature in hydrogels with shorter cross-linkers, demonstrating tunable diffusivity.
• Hydrogels with longer cross-linkers showed less temperature-dependent changes in drug diffusion due to physical entanglement stabilization.

Conclusions:

• The developed boronic ester-based hydrogel, functionalized with graphene oxide, provides an effective platform for on-demand, NIR-regulated drug release.
• Tunable network diffusivity through cross-linker design allows for precise control over drug release kinetics.
• This material holds promise for advanced controlled drug delivery systems requiring external triggers.