Bacterial Cellulose: A Sustainable Source for Hydrogels and 3D-Printed Scaffolds for Tissue Engineering

Bacterial cellulose is a biocompatible biomaterial with a unique macromolecular structure. Unlike plant-derived cellulose, bacterial cellulose is produced by certain bacteria, resulting in a sustainable material consisting of self-assembled nanostructured fibers with high crystallinity. Due to its purity, bacterial cellulose is appealing for biomedical applications and has raised increasing interest, particularly in the context of 3D printing for tissue engineering and regenerative medicine applications. Bacterial cellulose can serve as an excellent bioink in 3D printing, due to its biocompatibility, biodegradability, and ability to mimic the collagen fibrils from the extracellular matrix (ECM) of connective tissues. Its nanofibrillar structure provides a suitable scaffold for cell attachment, proliferation, and differentiation, crucial for tissue regeneration. Moreover, its mechanical strength and flexibility allow for the precise printing of complex tissue structures. Bacterial cellulose itself has no antimicrobial activity, but due to its ideal structure, it serves as matrix for other bioactive molecules, resulting in a hybrid product with antimicrobial properties, particularly advantageous in the management of chronic wounds healing process. Overall, this unique combination of properties makes bacterial cellulose a promising material for manufacturing hydrogels and 3D-printed scaffolds, advancing the field of tissue engineering and regenerative medicine

Chemopreventive functional food through selenium biofortification of cauliflower plants

The aim of this work was to develop a biotechnological approach for production of cauliflower as safe functional food, with an optimal content of chemopreventive compounds, by a protective biofortification, through selenium application together with betaine and spraying adjuvants. In the control and treated cauliflower plants we determined the amount of total selenium, glucosinolates (sulforaphane) and SAH (S-Adenosyl-homocysteine). We also assayed the chemopreventive effects of compounds formed in the treated cruciferous plants through in vitro tests, using human colorectal tumor cell line (CaCo2). Extracts of plants treated with selenium applied together with betaine and spraying adjuvant were significantly more active on reduction of tumoral cell viability than the extract of control plants. Cauliflower plants, obtained after our treatments for protective biofortification, were used to feed rabbits, for 10 days. The ingestion of biofortified cauliflower did not modify the hematological and biochemical parameters on the laboratory animals

New Hydrogel Formulations Based on Natural and Synthetic Polymers for Skin Regeneration

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

Evaluation of antioxidant and cytoprotective activities of <it>Arnica montana</it> L. and <it>Artemisia absinthium</it> L. ethanolic extracts

<p>Abstract</p> <p>Background</p> <p><it>Arnica montana</it> L. and <it>Artemisia absinthium</it> L. (Asteraceae) are medicinal plants native to temperate regions of Europe, including Romania, traditionally used for treatment of skin wounds, bruises and contusions. In the present study, <it>A. montana</it> and <it>A. absinthium</it> ethanolic extracts were evaluated for their chemical composition, antioxidant activity and protective effect against H₂O₂-induced oxidative stress in a mouse fibroblast-like NCTC cell line.</p> <p>Results</p> <p><it>A. absinthium</it> extract showed a higher antioxidant capacity than <it>A. montana</it> extract as Trolox equivalent antioxidant capacity, Oxygen radical absorbance capacity and 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging activity, in correlation with its flavonoids and phenolic acids content. Both plant extracts had significant effects on the growth of NCTC cells in the range of 10–100 mg/L <it>A. montana</it> and 10–500 mg/L <it>A. absinthium</it>. They also protected fibroblast cells against hydrogen peroxide-induced oxidative damage, at the same doses. The best protection was observed in cell pre-treatment with 10 mg/L <it>A. montana</it> and 10–300 mg/L <it>A. absinthium</it>, respectively, as determined by Neutral red and lactate dehydrogenase assays. In addition, cell pre-treatment with plant extracts, at these concentrations, prevented morphological changes induced by hydrogen peroxide. Flow-cytometry analysis showed that pre-treatment with <it>A. montana</it> and <it>A. absinthium</it> extracts restored the proportion of cells in each phase of the cell cycle.</p> <p>Conclusions</p> <p><it>A. montana</it> and <it>A. absinthium</it> extracts, rich in flavonoids and phenolic acids, showed a good antioxidant activity and cytoprotective effect against oxidative damage in fibroblast-like cells. These results provide scientific support for the traditional use of <it>A. montana</it> and <it>A. absinthium</it> in treatment of skin disorders.</p