Review 3D-Printed hydrogels for tissue engineering: a review.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Three-dimensional (3D) bioprinting of hydrogels is a key strategy in tissue engineering.
• It enables the creation of scaffolds with controlled architectures and biomimetic properties.
• This review covers advances in the last two decades, with historical context.

Purpose of the Study:

• To review recent advances in hydrogel-based 3D bioprinting.
• To compare major hydrogel printing techniques.
• To examine applications and translational challenges in tissue engineering.

Main Methods:

• Discussion and comparison of light-based, extrusion-based, and inkjet-based hydrogel printing systems.
• Examination of natural and synthetic hydrogels, including tough and composite hydrogels.
• Review of strategies for improving mechanical durability and functional performance.

Main Results:

• Hydrogel bioprinting techniques vary in resolution, fidelity, and cytocompatibility.
• Natural and synthetic hydrogels offer complementary advantages in bioactivity, printability, and mechanics.
• Advanced strategies enhance the performance of 3D-printed hydrogel constructs.

Conclusions:

• 3D bioprinting of hydrogels holds significant potential for diverse tissue engineering applications.
• Key challenges include scalability, vascularization, standardization, and regulatory approval.
• Further optimization is needed for successful clinical translation.