Interparticle Crosslinked Ion-responsive Microgels for 3D and 4D (Bio)printing Applications

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Soft Robotics

Background:

• Microgels offer superior diffusion compared to bulk hydrogels.
• Stimuli-responsive microgels are promising bioactive and self-supporting biomaterials.

Purpose of the Study:

• Develop interparticle-crosslinked, ion-responsive microgels for 3D and 4D bioprinting.
• Create self-supporting microgels that preserve void spaces for cell migration and vascularization.
• Investigate ion-responsive shrinking behavior via the Hofmeister effect.

Main Methods:

• Fabrication of spherical (µS) and random-shaped (µR) ion-responsive microgels.
• Utilized interparticle crosslinking to eliminate filler hydrogels.
• Validated microgels in extrusion-based, embedded, intraembedded, and aspiration-assisted bioprinting techniques.
• Achieved multi-material 4D printing by combining ion-responsive and non-responsive microgels.

Main Results:

• µR microgels showed superior mechanical properties and packing density.
• Microgel constructs supported angiogenesis with tunable vessel sizes.
• Demonstrated excellent shear-thinning, self-healing properties, and high print fidelity.
• Generated dynamic 4D printed structures like coiling filaments and folding sheets.

Conclusions:

• Developed novel ion-responsive microgels for advanced bioprinting applications.
• Enabled fabrication of scalable, dynamic constructs for tissue models and soft robotics.
• The ion-responsive nature and interparticle crosslinking offer new possibilities in biomaterial design.