A high-strength collagen-based antimicrobial film grafted with ε-polylysine fabrication by riboflavin-mediated ultraviolet irradiation for pork preservation.

In this study, a UV-cured collagen-based film (C-P-H film) with high mechanical strength and antimicrobial properties was developed by riboflavin-mediated ultraviolet irradiation of collagen solution containing histidine-modified ε-polylysine. Fourier transform infrared analysis indicated that covalent cross-linking was formed between the collagen molecule and the histidine-grafted ε-polylysine. Compared with the pure collagen film, the C-P-H film containing 5 wt% histidine-modified ε-polylysine showed higher tensile strength (145.98 MPa), higher thermal denaturation temperature (76.5 °C), lower water vapor permeability (5.54 × 10-11 g m-1 s-1 Pa) and excellent antimicrobial activities against Escherichia coli and Staphylococcus aureus. In addition, the wrapping of the C-P-H film effectively inhibited bacterial growth of pork during storage time, successfully prolonging the shelf-life of pork by approximately 4 days compared to that of plastic wrap. These results suggested that collagen-based film grafted with histidine-modified ε-polylysine via riboflavin-mediated ultraviolet irradiation process had a great potential for pork preservation.

A bioactive composite sponge based on biomimetic collagen fibril and oxidized alginate for noncompressible hemorrhage and wound healing.

The study focuses on developing a bioactive shape memory sponge to address the urgent demand for short-term rapid hemostasis and long-term wound healing in noncompressible hemorrhage cases. A composite sponge was created by spontaneously generating pores and double cross-linking under mild conditions using biomimetic collagen fibril (BCF) and oxidized alginate (OA) as natural backbone, combined with an inert calcium source (Ca) from CaCO3-GDL slow gelation mechanism. The optimized BCF/OACa (5/5) sponge efficiently absorbed blood after compression and recovered to its original state within 11.2 ± 1.3 s, achieving physical hemostatic mechanism. The composite sponge accelerated physiological coagulation by promoting platelet adhesion and activation through BCF, as well as enhancing endogenous and exogenous hemostatic pathways by Ca2+. Compared to commercial PVA expanding hemostatic sponge, the composite sponge reduced bleeding volume and shortened hemostasis time in rat liver injury pick and perforation wound models. Additionally, it stimulated fibroblast migration and differentiation, thus promoting wound healing. It is biodegradable with low inflammatory response and promotes granulation tissue regeneration. In conclusion, this biocomposite sponge provides multiple hemostatic pathways and biochemical support for wound healing, is biologically safe and easy to fabricate, process and use, with significant potential for clinical translation and application.