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

Abstract

Bone tissue engineering is a complex process where the scaffold plays a significant role as it contributes to phenotypically stable tissue formation and stem cell differentiation. These properties can be reached with a composite scaffold of alginate‐gelatin three‐dimensional network structure. The primary purpose of this study was to design a three‐dimensional and porous alginate‐gelatin hydrogel and evaluate the effects of pore size on cell morphology, cell adhesion, and proliferation under different osteogenic microenvironments. For this purpose, hydrogels with various concentrations of alginate and gelatin were prepared by mixing 4% (w/v) alginate and 6% gelatin (4A6G), or 3% (w/v) alginate and 5% (w/v) gelatin (3A5G) and cross‐linked with 2% (w/v) CaCl2. The pore size of these hydrogels was optimized using a very simple method based on different freezing and thawing cycles. The scanning electron microscopy (SEM) analysis showed porous structures with different pore sizes, ranging from 340 µm ± 30 µm with the 4A6G hydrogel to 635 µm ± 25 µm with the 3A5G hydrogel. The stiffness measurement showed a significant difference, with approximately 26.3 kPa ± 0.6 KPa for the 4A6G hydrogel and 21.6 kPa ± 0.2 KPa for the 3A5G hydrogel. Cell interaction with both types of hydrogel showed higher cell adhesion and proliferation rates in the hydrogel with larger pore size. Bone tissue formation, as evaluated by RT‐PCR, ALP (alkaline phosphatase) activity, and ARS (Alizarin Red S) staining, demonstrated strong osteogenic potential of the 3A5G hydrogel compared to the 4A6G. In summary, the 3A5G hydrogel (3% (w/v) alginate and 5% (w/v) gelatin) can be considered a potential material for bone tissue regeneration construction due to its biodegradability and favorable bone‐forming properties.This article is protected by copyright. All rights reserved.