Programmable Injectable Dual-Responsive Hydrogels with NIR Ratiometric Self-Monitoring of pH/Ca²⁺ for Sensing and...

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Soft Matter Physics

Background:

• Injectable hydrogels are advanced smart biomaterials.
• Developing self-monitoring materials is crucial for advanced applications.

Purpose of the Study:

• To create injectable dual-responsive hydrogel composites with near-infrared (NIR) emission.
• To enable self-monitoring capabilities in hydrogels through phototriggered cross-linking.

Main Methods:

• Fabrication of hydrogels from nonradiative energy transfer (NRET) nanoprobes and doubly cross-linked microgel (DX MG) building blocks.
• Utilizing phototriggered covalent cross-linking of shear-thinning microgels for dual responsiveness to pH and Ca²⁺.
• Employing NIR ratiometric photoluminescence (RMPL) for monitoring hydrogel properties.

Main Results:

• Developed easily prepared, injectable hydrogels with reversible pH (4.5-7.4) and Ca²⁺ (0.005-0.08 M) responsiveness.
• Achieved tunable modulus and swelling ratios monitored via NIR RMPL.
• Demonstrated a bilayer actuator capable of simultaneous pH/Ca²⁺ response and tortuosity monitoring using NIR RMPL.

Conclusions:

• This study presents the first self-monitoring hydrogel actuator utilizing NIR ratiometric photoluminescence.
• The developed hydrogels offer significant promise for photoluminescence (PL) bionic-driven soft matter and biomedical applications.
• The tunable and responsive nature of these hydrogels facilitates real-time monitoring in various environments.