Collagen from Iris squid grafted with polyethylene glycol and collagen peptides promote the proliferation of fibroblast through PI3K/AKT and Ras/RAF/MAPK signaling pathways

Tracheal regeneration and mesenchymal stem cell augmenting potential of natural polyphenol-loaded gelatinmethacryloyl bioadhesive

Hydrogels incorporating natural biopolymer and adhesive substances have extensively been used to develop bioactive drugs and to design cells encapsulating sturdy structure for biomedical applications. However, the conjugation of the adhesive in most hydrogels is insufficient to maintain long-lasting biocompatibility inadequate to accelerate internal organ tissue repair in the essential native cellular microenvironment. The current work elaborates the synthesis of charged choline-catechol ionic liquid (BIL) adhesive and a hydrogel with an electronegative atom rich polyphenol (PU)-laden gelatinmethacryloyl (GelMA) to improve the structural bioactivities for in vivo tracheal repair by inducing swift crosslinking along with durable mechanical and tissue adhesive properties. It was observed that bioactive BIL and PU exhibited potent antioxidant (IC 50 % of 7.91 μg/mL and 24.55 μg/mL) and antibacterial activity against E. coli, P. aeruginosa and S. aureus. The novel integration of photocurable GelMA-BIL-PU revealed outstanding mechanical strength, biodegradability and sustained drug release. The in vitro study showed exceptional cell migration and proliferation in HBECs, while in vivo investigation of the GelMA-BIL-PU hydrogel on a rat's tracheal model revealed remarkable tracheal reconstruction, concurrently reducing tissue inflammation. Furthermore, the optimized GelMA-BIL-PU injectable adhesive bioink blend demonstrated superior MSCs migration and proliferation, which could be a strong candidate for developing stem cell-rich biomaterials to address multiple organ defects.

The targeted development of collagen-active peptides based on composite enzyme hydrolysis: a study on the structure-activity relationship

Fish collagen, derived from sustainable sources, offers a valuable substrate for generating peptides with diverse biofunctionalities. In this study, alkaline, papain, and ginger protease were used to enzymatically hydrolyze fish skin collagen. The peptide molecular weight distribution and sequence were measured using HPLC and ICP-MS-MS, with papain/alkaline protease (AP) and papain/alkaline/ginger protease (APG) hydrolyzed samples compared. As the results showed, the incorporation of ginger protease was useful for increasing the degree of hydrolysis, with the content of <400 Da peptides increasing from 49.82% to 58.56%. The identified peptide sequence in the APG sample had more proline at the C-terminal. The peptides were separated into two components (different in molecular weight) using gel column chromatography. The molecular weight distribution, amino acid composition, ACE inhibitory activity, and fibroblast proliferation activity of the collected components were measured. In comparison, the contents of proline and hydroxyproline in the larger peptides decreased obviously after combined hydrolysis by ginger protease, reflecting the formation of a peptide sequence of smaller molecular weight containing glycine and hydroxyproline. The combined hydrolysis of ginger protease was beneficial for the improvement of the ACE inhibitory activity of the sample. However, the fibroblast proliferation activity of AP was higher than that of APG, indicating that further hydrolysis by ginger protease may destroy the hydroxyproline at the end of the peptide sequence. This study proposed a creative directional hydrolysis method and provided practical guidance for the production of collagen peptides with enhanced functional activity.