Table 2.

Comparison of natural, synthetic, and hybrid hydrogels for cartilage tissue engineering.

Hydrogel Type	Examples (Source)	Pros	Cons	References
Natural Hydrogels	Alginate (Marine, Algae) Collagen (Animal) Hyaluronic Acid (Animal or Bacterial) Chitosan (Marine, Crustacean) Gelatin (Animal) Fibrin (Animal) Cellulose (Plant)	- Bioactivity and biocompatibility - Biodegradation - Supports cell adhesion, proliferation, and differentiation - Anti-inflammation and antioxidant	- Poor mechanical properties - Unpredictable degradation kinetics - Potential for immunogenicity	[33,39]
Synthetic Hydrogels	Polyethylene Glycol (PEG) Poly(N-isopropylacrylamide) (PNIPAAm) Poly(vinyl alcohol) (PVA) Poly(lactic-co-glycolic acid) (PLGA) Polycaprolactone (PCL)	- Precise control over mechanical and biochemical properties - Customizable scaffold design - Reproducible	- Risk of foreign body reaction - Poor biological activity - Uncertain long-term biocompatibility	[34,40]
Hybrid Hydrogels	Combinations of natural and synthetic components	- Synergizes advantages of both natural and synthetic materials - Balances bioactivity and mechanical strength	- Complexity in design and synthesis - Potential for uneven degradation or integration	[40,41,42]