The emerging strategy of tissue engineering for the management of end-stage organ failure and associated complications mainly relies on ECM mimicking scaffolds for neo-tissue genesis. In the current study, novel polyethylene glycol interpenetrated cross-linked hydrogel scaffold based on a co-polysaccharide (PIAC) synthesized from two marine heteropolysaccharides, alginate and chitosan, was designed. Partially cross-linked (PIAC-P) and fully cross-linked hydrogels (PIAC-F) were prepared. The physiochemical evaluations of both the hydrogels revealed the presence of alginate fraction and extensive –OH groups on the surface, sufficient water content and water holding capacity. The porosity and bulk density were also appreciable. The scaffolds were hemocompatible and were able to adsorb appreciable plasma proteins on to the surface. MTT assay on hydrogel extracts and direct contact assay showed the nontoxic effects of fibroblast cells upon contact with the hydrogel. Live/dead assay using ethidium bromide/acridine orange cocktail on fibroblast cells grown on the hydrogels after 5 days of initial seeding displayed green nucleus revealing the non-apoptotic cells. PIAC-P hydrogels were superior to certain aspects due to the availability of free functional groups than PIAC-F where most of these groups were utilized for cross-linking. The biological evaluations confirmed the healthy being and 3D growth of fibroblasts on the porous networks of both the hydrogels. The present hydrogel can form an ECM mimic and can form a potent candidate for various tissue engineering applications.

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<p class="Default">Antioxidants play a central role in the prevention of carcinogenesis. The most natural compounds exhibit their protective effects by eliciting antioxidant potential. Sulfated polysaccharide was isolated from the brown algae <em>Padina tetrastromatica</em>, then purified and evaluated for its composition and <em>in vitro </em>antioxidant and antimitotic activities. Both ethanolic sulfated polysaccharide (ESPS) and ethanolic sulfated polysaccharide-column purified (ESPS-CP) exhibited considerable amount of carbohydrates (11.2% and 17.6%), sulfate (11.4% and 7.4%), fucose (5.5% and 15.7%), uronic acid (4.7% and 11.8%), xylose (0.5% and 0.03%) and sulfated polysaccharide (2.4% and 12.7%) content. The FTIR analysis and phytochemical screening also confirmed the presence of sulfated polysaccharides. In the <em>in vitro</em> antioxidant activity determination using DPPH (1-1-diphenyl 2-picryl hydrazyl) radical scavenging activity, hydroxyl radical scavenging activity, superoxide anion scavenging activity, hydrogen peroxide scavenging activity, total antioxidant activity and reducing power, ESPS showed more activity than ESPS-CP. In the case of nitric oxide radical scavenging, ESPS-CP was found to be more effective. At a concentration of 2mg/ml, both samples were potent antioxidants with significant IC₅₀ values. The antimitotic studies such as mitotic index in onion root tips and sprouting assay in green gram seeds also proved that both the extracts are able to prevent mitosis. The extrapolation of these results can find opportunities in therapeutic regiments of cancer.<strong></strong></p>

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Scaffold-guided tissue regeneration using hydrogels has been emerging as an ideal alternative for the management of terminal-stage organ damage. Design of scaffolds for tissue regrowth mainly focuses on their immuno/biocompatibility as well as physiochemical characteristics. The focus of this study is on the biocompatibility evaluations of a panel of four hydrogel scaffolds fabricated using alginate, chitosan and hydroxyapatite reinforced with poly(ethylene glycol). The hydrogels were subsequently cross-linked with calcium ions and glutaraldehyde. Immunocompatibility was assessed by interacting Raw 264.7 cell lines with these hydrogels. MTT cell viability assay revealed the non-cytotoxic nature of the hydrogels, and the macrophages grown in contact with the hydrogels exhibited no alteration in their morphology and were similar to the untreated normal cells. The concentration of nitric oxide, activity of myeloperoxidase and the messenger ribonucleic acid transcripts of proinflammatory cytokines, interleukin 6 and tumour necrosis factor alpha exhibited no considerable increase in the macrophages cultured with the hydrogels when compared to lipopolysaccharide-stimulated cells. In short, the absence of macrophage activation on contact with hydrogels is a clear indication of their in vitro immunocompatibility, suggesting their potential application as tissue engineering templates.

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