The skin, which represents about 16% of the total body mass, acts as a protective barrier against external microbial factors [¹]. Therefore, damaged tissues, especially burns, require rapid local coverage to avoid infections and to ensure the protective barrier function of the skin [²]. The aim of this study was to design and characterize new hydrogel formulations based on natural and synthetic polymers and that were biodegradable and cytocompatible to serve as temporary dressings with regenerative properties for skin wound healing. The proposed experimental variants of the hydrogels are based on mixtures of gelatin (Gel), sodium alginate (Alg), polyvinyl alcohol (PVA), and methylcellulose (MC1500) in different weight ratios: Gel-Alg (1:0.75, g/g), Gel-Alg-PVA (1:0.27:0.18, g/g/g) and Gel-Alg-MC1500 (1:0.26:0.35, g/g/g). Physicochemical and biochemical characterizations were performed to determine the swelling degree, biodegradation in physiological conditions (pH 7.4, 37 °C) and in the presence of collagenase (mimicking the inflamed wounded milieu), viscosity, and syneresis, while their ultrastructure was investigated by SEM analysis [³]. The L929 murine fibroblast culture was used to assess the in vitro cytocompatibility of the hydrogels after 24 h and 48 h of cultivation using quantitative MTT and LDH assays [⁴]. Cell morphology was observed in treated cultures by light microscopy after Giemsa staining. The physicochemical and biochemical analyses indicated that the novel polymeric hydrogels variants had a good swelling capacity due to the presence of Alg, had an adjustable viscosity, and controlled biodegradation over time in both physiological and inflamed conditions. Two mixture variants were outlined: Gel-Alg-PVA with reduced porosity and low biodegradability over time and Gel-Alg-MC1500 with increased porosity and higher biodegradation over time, even in the physiological environment. The SEM morphology observations showed that the hydrogels had a dense and microporous structure, with pores of irregular shapes and sizes, which could ensure skin protection against external microbial agents while also maintaining the required degree of humidity and oxygen exchange with the external environment. In vitro quantitative tests indicated a high degree of cytocompatibility for all of the tested hydrogels, with cell viability percentages higher than 90%. The cell morphology observations revealed that in the presence of hydrogel samples, the L929 murine fibroblasts maintained their normal phenotype, and the cell density was similar to that of the negative control (untreated cells). Overall, our findings indicated that the hydrogels containing synthetic polymers (Gel-Alg-PVA, Gel-Alg-MC1500) had adequate physicochemical, biochemical, and biological properties that should be further tested to determine their role as biomaterials for skin tissue engineering applications.

Osteochondral regeneration is a major challenge due to the different composition of cartilage and subchondral bone and different biochemical, biomechanical and biological properties. For this reason, a biomimetic scaffold is necessary to provide different biological signals needed to allow for osteochondral regeneration [¹]. This study aims to design novel biodegradable cross-linked composite hydrogels based on gelatin and polysaccharidic components (chondroitin-4-sulphate and hyaluronic acid), mixed with akermanite and enriched with small bioactive molecule (icariin). Akermanite was used as a better alternative to conventional ceramics due to its bone-like apatite formation ability and good bioactivity [²]. Icariin (Ica) flavonoid (from traditional Chinese medicine Epimedium herb) was used as substitute for growth factors to enhance cell proliferation and chondrogenic and osteogenic differentiation [3]. Variants of biodegradable cross-linked composite hydrogel based on gelatin, polysaccharidic components (chondroitin-4-sulphate and hyaluronic acid), in two ratios of 2:0.8:0.2 and 2:0.08:0.02 (w/w/w), were developed and mixed with akermanite, at a ratio of 2:1 (w/w). Subsequently, both composite hydrogel variants were cross-linked with (N,N-(3-dimethylaminopropyl)-N-ethyl carbodiimide (EDC) and enriched with small bioactive molecule (icariin). The obtained cross-linked composite hydrogel variants enriched with Ica were characterized related to enzymatic biodegradation (type I collagenase), swelling capacity, degree of cross-linking (TNBS assay), and morphology (SEM). Their cytocompatibility was evaluated by analyses of cell viability and cellular cycle (flow cytometry), cell proliferation (Neutral Red assay), and cell adhesion to composite hydrogels (SEM) using NCTC clone L929 cell line. The final results show that both cross-linked composite hydrogel variants enriched with Ica presented optimal physicochemical and structural properties to be used as a scaffold for osteochondral healing. Our data did not reveal any toxicity of composite hydrogels in the NCTC cell line within the tested range of concentrations (10–50 mg/mL). Additionally, cells were capable of spreading and proliferating on the surface of composite hydrogels. The designed biodegradable cross-linked composites enriched with Ica are recommended for further studies as natural temporary scaffolds, which can allow both cartilage and subchondral regeneration with implications for the management of osteochondral healing.

The aim of this work was to obtain a mixture of polyphenols and polysaccharides, extracted from forest fruit pomace (a side stream of forest fruit juice production) and chia seeds with a synergic antioxidant activity that will be further encapsulated and used in a fortified protein bar

Introduction: Nutraceuticals are food or parts of a food that provide medicinal or health benefits, including the prevention and treatment of disease.

Freshwater fish skin and bones are usually by-products of the fish processing industry.