Preparation and characterization of wound healing hydrogel based on fish skin collagen and chitosan cross-linked by dialdehyde starch.

Hydrogels due to high water absorption capacity, flexibility, biodegradability properties and also the ability to provide a moist environment, same as native extracellular, are widely used for wound healing applications. Developing multifunctional hydrogels using biomaterial is an emerging approach in this area. Collagen and chitosan are known as excellent biomaterials due to their properties, functionality, and sustainable sources. They also have good biocompatibility and biodegradability, suitable for wound healing hydrogels. In this study, the physicochemical characterization, morphology, and biocompatibility of collagen/chitosan/ dialdehyde starch hydrogel (Col/Ch/DAS) were evaluated. Type I collagen was extracted from silver carp skin by-product. DAS was synthesized by a one-step method of acid hydrolysis and oxidation. Hydrogels were made from collagen (4 % w/v) and chitosan mix (2 % w/v) and added DAS (2 % w/v) (0.5, 1.0 and 1.5 ml) as a cross-linker to enhance the physicochemical behaviors of the hydrogels. Swelling ratio, biodegradation, water vapor transmission rate (WVTR), surface morphology and the interactions between functional groups of polymers used in the hydrogel were evaluated. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) test of extracted collagen indicated the presence of two different α-chains in collagen and confirmed type I collagen. The results showed that DAS content significantly affected the swelling ratio and biodegradability of hydrogels (P < 0.05). Col/Ch/Das0.5 hydrogel showed the highest swelling and biodegradability compared to other hydrogels (P < 0.05). Col/Cs/DAS hydrogels showed suitable water vapor transmission for wound dressing. The Fourier transform infrared spectroscopy (FTIR) results showed that covalent bonds formed via acetalization and Schiff base reaction. The results suggested that the prepared hydrogel from silver carp fish skin collagen has excellent potential as a new wound dressing for medical and biomedical applications such as wound healing.

The Effects of Zataria multiflora Boiss Essential Oil and Nisin on Chemical Characteristics of Rainbow Trout Fillet Stored at 4 °C.

This study evaluated the effects of Zataria multiflora essential oil (EO) and nisin on fresh rainbow trout fillets during storage at 4 °C. Treatments included the following: A (control samples without EO and nisin), E1 (treated samples with 0.2% EO), E2 (treated samples with 0.4% EO), N (treated samples with 150 IU nisin/g), E1N (treated samples with 0.2% EO and nisin) and E2N (treated samples with 0.4% EO and nisin). Chemical and oxidation changes were investigated in this study as the functions of treatment and storage time. E1N and E2N had better effects on oxidation changes and maintaining values of peroxide value and thiobarbituric acid than A, E1, E2 and N treatments. Lower total volatile base nitrogen was found in E2N than in other treatments during storage time.