4D Printed Programmable Shape-Morphing Hydrogels as Intraoperative Self-Folding Nerve Conduits for Sutureless...

Area of Science:

• Biomaterials Engineering
• Regenerative Medicine
• Tissue Engineering

Background:

• Few implantable 4D printed biomaterials exist, with slow deformations limiting surgical use.
• Hydrogels offer potential for dynamic shape changes but require precise control.

Purpose of the Study:

• To engineer a 3D printable hydrogel with programmed in vivo shape deformation for nerve repair.
• To create self-assembling nerve conduits using 4D printing technology.

Main Methods:

• Developed a hydrogel system with controlled swelling for extrusion-based 3D printing.
• Utilized computational prediction and experimental validation of hydrogel shape deformations.
• Coated 3D printed hydrogels with gelatin-rich nanofibers to enhance cell growth.
• Evaluated the in vivo performance of 4D printed hydrogel tubes as nerve-guiding conduits in a rat sciatic nerve defect model.

Main Results:

• Achieved excellent printability and programmed shape deformations in the engineered hydrogels.
• Demonstrated rapid in vivo self-rolling of 3D printed hydrogel sheets into tubes.
• Successfully used the 4D printed hydrogel tubes to repair sciatic nerve defects in rats.
• Observed minimized surgical complexity and assisted peripheral nerve healing, confirmed by histological and functional assessments up to 45 days.

Conclusions:

• 3D printed hydrogels can be designed for programmed in vivo shape changes, creating effective 4D printed tissue constructs.
• This 4D printing approach offers a promising solution for peripheral nerve damage repair.
• The technology has potential for broader applications in regenerative medicine.