An enzyme-sensitive PEG hydrogel based on aggrecan catabolism for cartilage tissue engineering

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Cartilage defects pose significant clinical challenges.
• Current tissue engineering strategies require improved biomaterials for cartilage regeneration.
• Developing degradable scaffolds that mimic native cartilage extracellular matrix is crucial.

Purpose of the Study:

• To develop and evaluate a novel, cartilage-specific degradable hydrogel for cartilage tissue engineering.
• To assess the hydrogel's degradation behavior and its impact on chondrocyte matrix production.
• To compare the engineered cartilage matrix with native and hypertrophic cartilage characteristics.

Main Methods:

• Fabrication of photoclickable poly(ethylene glycol) (PEG) hydrogels with aggrecanase-cleavable peptide crosslinks.
• Encapsulation of bovine chondrocytes from juvenile and adult donors, including lipopolysaccharide (LPS)-stimulated cells.
• Culturing engineered constructs for 12 weeks and evaluating mechanical properties, swelling, matrix deposition, and inflammatory response.

Main Results:

• The hydrogel showed a twofold decrease in compressive modulus over 12 weeks with limited swelling, indicating controlled degradation.
• Chondrocytes from both juvenile and adult donors deposited aggrecan and collagen II, forming a hyaline-like matrix.
• Aggrecanase activity was elevated, but did not accelerate bulk degradation; LPS reduced matrix production without affecting enzyme activity.
• Non-degradable hydrogels led to hypertrophic cartilage markers (collagens I, X).
• No inflammatory response was observed in chondrocytes cultured within the degradable hydrogels.

Conclusions:

• The developed aggrecanase-sensitive hydrogel is effectively degraded by chondrocytes.
• The hydrogel promotes the formation of hyaline-like engineered cartilage, showing potential for cartilage regeneration.
• This biomaterial offers a promising platform for developing advanced cartilage tissue engineering therapies.