Injectable and Conductive Granular Hydrogels for 3D Printing and Electroactive Tissue Support

Area of Science:

• Biomaterials Science
• Materials Engineering
• Tissue Engineering

Background:

• Conductive hydrogels are crucial for mimicking biological electrophysiological environments and for therapeutic applications.
• Existing conductive hydrogels often suffer from poor gelation, brittleness, or inadequate conductivity, limiting their use in injectable or 3D printing applications.
• There is a need for advanced conductive hydrogels that are injectable, possess good mechanical properties, and exhibit high conductivity.

Purpose of the Study:

• To develop a novel injectable conductive granular hydrogel system.
• To enhance the conductivity and mechanical properties of hydrogels for biomedical applications.
• To demonstrate the versatility of the developed hydrogel for 3D printing and tissue repair.

Main Methods:

• Fabrication of hydrogel microparticles (microgels) using microfluidics and water-in-oil emulsions.
• In situ metal reduction process to incorporate metal nanoparticles into the microgels.
• Jamming of microgels to form injectable granular hydrogels with tunable conductivity.

Main Results:

• The granular hydrogels exhibited significantly higher conductivity compared to bulk hydrogels or those with encapsulated nanoparticles, attributed to metal nanoparticles at the jammed interface.
• Conductivity could be precisely tuned by mixing conductive and non-conductive microgels.
• The hydrogels were successfully applied in 3D printing of lattices and for bridging muscle defects.

Conclusions:

• The developed conductive granular hydrogels offer an injectable and versatile platform with enhanced conductivity.
• This approach overcomes limitations of current conductive hydrogels, enabling applications in regenerative medicine and advanced material fabrication.
• The tunable conductivity and injectability make these hydrogels promising for various biomedical and electronic applications.