Methacrylated pullulan/polyethylene (glycol) diacrylate composite hydrogel for cartilage tissue engineering

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Polymer Chemistry

Background:

• Pullulan hydrogels are limited in cartilage repair due to poor mechanical properties and rapid degradation.
• Developing robust and biocompatible hydrogels is crucial for effective articular cartilage regeneration.

Purpose of the Study:

• To fabricate and characterize novel photo-crosslinkable pullulan/polyethylene glycol diacrylate (PulMA/PEGDA) hybrid hydrogels.
• To evaluate the mechanical properties, degradation rate, and biocompatibility of these hydrogels for cartilage tissue engineering.

Main Methods:

• Methacrylated pullulan (PulMA) was synthesized and combined with polyethylene glycol diacrylate (PEGDA).
• PulMA/PEGDA hydrogels were formed via photopolymerization using lithium phenyl(2,4,6-trimethylbenzoyl)phosphinate (LAP) as a photoinitiator.
• Mechanical properties, degradation rates, and *in vitro* cell responses (adhesion, proliferation, GAG synthesis) of encapsulated mesenchymal stem cells (MSCs) were assessed.

Main Results:

• Increasing PEGDA concentration enhanced mechanical strength (storage modulus up to 16.0 × 10³ Pa, compressive modulus up to 1.17 MPa) and reduced degradation rate (residual mass increased to 86.8%).
• The PulMA/PEGDA hydrogels demonstrated excellent biocompatibility, supporting MSC adhesion and proliferation.
• Encapsulated MSCs exhibited glycosaminoglycan (GAG) synthesis and maintained a chondrogenic phenotype in the presence of TGF-β3.

Conclusions:

• Photo-crosslinked PulMA/PEGDA hybrid hydrogels offer improved mechanical properties and controlled degradation compared to pure pullulan hydrogels.
• These hydrogels show significant promise as scaffolds for articular cartilage repair and regeneration due to their biocompatibility and ability to support chondrogenesis.