Fish skin gelatin-based adhesive hydrogels loading cod peptides with osteogenic activity for bone tissue engineering

Loading bioactive molecules, such as proteins and peptides, into hydrogels is a promising strategy to expand the application of hydrogels in tissue engineering. Herein, a novel bioactive gelatin hydrogel loading peptide derived from Atlantic cod (Gadus morhua) was developed for bone tissue engineering, which was constructed on the NaIO4-mediated oxidative coupling of dopamine-modified gelatin (Gel-DA). The Gel-DA hydrogel incorporated with cod peptides (0.5 mg/mL) showed an acceptable gelation time (130.22 & PLUSMN; 7.15 s) and maintained a continuous microscopic pore structure. Besides, the compression strength and adhesive strength of Gel-DA hydrogel with 0.5 mg/mL cod peptides reached 136.33 & PLUSMN; 38.95 kPa and 4.93 & PLUSMN; 0.80 kPa, respectively. Meanwhile, all hydrogels exhibited excellent mechanical stability. The incorporation of cod peptides (0.1, 0.5 mg/mL) was beneficial to the adhesion and spreading of mouse osteoblasts precursor cells MC3T3-E1. Moreover, the alkaline phosphatase (ALP) activity of the Gel-DA hydrogel loading 0.5 mg/mL peptides was significantly increased from 0.16 & PLUSMN; 0.02 U.mg/protein to 0.19 & PLUSMN; 0.02 U.mg/protein as compared to Gel-DA hydrogel. These results indicated that the GD-CPs hydrogel is an effective candidate material for bone tissue engineering.