Negative Printing for the Reinforcement of In Situ Tissue-Engineered Cartilage

Area of Science:

• Biomaterials Engineering
• Tissue Engineering
• Regenerative Medicine

Background:

• In situ cartilage engineering aims for direct chondral repair using cell-laden hydrogels.
• Soft hydrogels require enhanced mechanical properties to withstand physiological loads during cartilage regeneration.

Purpose of the Study:

• To develop a reinforced hydrogel system for in situ cartilage repair.
• To investigate the efficacy of 3D printed polycaprolactone scaffolds in providing mechanical support to cell-laden hydrogels.

Main Methods:

• Developed a system combining gelatin methacryloyl hydrogel with human adipose-derived mesenchymal stem cells and 3D printed polycaprolactone reinforcement structures.
• Utilized negative embodied sacrificial template 3D printing to create lattice-based scaffolds with varying porosity and stiffness.
• Evaluated the mechanical stability and chondrogenic potential of the combined hydrogel-scaffold construct over 41 days.

Main Results:

• Generated eight lattice-based reinforcement structures with stiffnesses ranging from 28 ± 5 kPa to 2853 ± 236 kPa.
• The 'hex prism edge' scaffold design combined with cellular hydrogel maintained stable stiffness for 41 days.
• No significant difference in sulfated glycosaminoglycan production or Type II Collagen gene expression was observed between hydrogel-only and hydrogel-scaffold groups.

Conclusions:

• Negative embodied sacrificial template 3D printing enables integration of bulk reinforcement for hydrogels in cartilage engineering.
• This approach provides mechanical stability without compromising chondrogenic matrix production by stem cells.
• The developed system shows promise for enhancing in situ cartilage regeneration strategies.