Enhancing Osteogenic Potential in Bone Tissue Engineering: Optimizing Pore Size in Alginate–Gelatin Composite Hydrogels

Abstract

Bone tissue engineering relies on crucial scaffolds for tissue formation and stem cell differentiation. A composite scaffold of alginate-gelatin effectively supports these processes. This study aims to design a porous alginate-gelatin hydrogel and assess pore size effects on cell behavior, focusing on morphology, adhesion, and proliferation in distinct osteogenic environments. Hydrogels are prepared using various alginate-gelatin concentrations: 4% alginate and 6% gelatin (4A6G) or 3% alginate and 5% gelatin (3A5G), cross-linked with 2% CaCl2. Pore size optimization employs simple freezing and thawing cycles. Scanning electron microscopy reveals varying pore sizes: 340 µm ± 30 µm for 4A6G and 635 µm ± 25 µm for 3A5G. Stiffness measurements indicate significant differences: ≈26.3 kPa ± 0.6 KPa for 4A6G and 21.6 kPa ± 0.2 KPa for 3A5G. Cell interaction studies demonstrate higher adhesion and proliferation rates in larger-pored hydrogels. Evaluation of bone tissue formation, including RT-PCR, ALP activity, and ARS staining, reveal superior osteogenic potential in the 3A5G hydrogel compared to 4A6G. In conclusion, the 3A5G hydrogel (3% alginate and 5% gelatin) holds promise for bone tissue regeneration due to its biodegradability and favorable bone-forming properties.