Fabrication and characterization of chitosan based collagen/ gelatin composite scaffolds from big eye snapper Priacanthus hamrur skin for antimicrobial and anti oxidant applications.

In this study, for developing a scaffold for tissue engineering from fish processing wastes, a hierachial collagen/gelatin/chitosan novel porous scaffold was fabricated using blends of collagen and gelatin extracted from the skins of Marine big eye snapper Priacanthus humrur. Scaffolds were developed by mechanical spinning of chitosan and by mixing of collagen and gelatin solutions followed by freeze drying and subsequent crosslinking of polymers. The scaffolds were evaluated for rheological properties - porosity, apparent density and swelling capacity to assess their mechanical property.Gelatin/chitosan composition shown very high porosity(81.02%) and incorporation of collagen shown higher density in Collagen/gelatin/chitosan scaffolds (0.0522g/cm3) and collagen/chitosan scaffolds (0.0468 g/cm3).Morphology of the prepared scaffolds were analyzed by Scanning Electron Microscopy which showed reduced pore size of 10 to 20µ in Collagen/gelatin/Chitosan composite, 5 to 10µ in gelatin/chitosan composites and 2-5µ in collagen/chitosan composites. FTIR analysis showed intense peaks ranging 1120 -11267 cm-1 in the three different scaffolds that are denoted as CH groups. In-vitro antioxidant investigation through DPPH assay showed that the composite 3 in 1 mg/ml concentration exhibited higher antioxidant potential (70%). In contrast, ABTS scavenging assay identified composite1 in 1 mg/ml had good antioxidant activity with highest percentage of inhibition (29.5%). The scaffolds were also evaluated for anti microbial properties through disc diffusion assay. The results showed maximum inhibition- 14 mm, 12 mm and 14 mm for 200 µg of the sample for collagen/chitosan, gelatin/chitosan and collagen/gelatin/chitosan scaffolds respectively towards E.Coli and 20 mm, 20 mm and 24 mm towards S.aureus. The zone of inhibition against E. coli and S. aureus for the three scaffolds was comparatively lower and that could be due to the presence of chitosan. The findings of the study indicates that the bioscaffolds are expected to have wide application in tissue engineering.

Evaluation of zinc oxide nanoparticles toxicity on marine algae chlorella vulgaris through flow cytometric, cytotoxicity and oxidative stress analysis.

The increasing industrial use of nanomaterials during the last decades poses a potential threat to the environment and in particular to organisms living in the aquatic environment. In the present study, the toxicity of zinc oxide nanoparticles (ZnO NPs) was investigated in Marine algae Chlorella vulgaris (C. vulgaris). High zinc dissociation from ZnONPs, releasing ionic zinc in seawater, is a potential route for zinc assimilation and ZnONPs toxicity. To examine the mechanism of toxicity, C. vulgaris were treated with 50mg/L, 100mg/L, 200mg/L and 300 mg/L ZnO NPs for 24h and 72h. The detailed cytotoxicity assay showed a substantial reduction in the viability dependent on dose and exposure. Further, flow cytometry revealed the significant reduction in C. vulgaris viable cells to higher ZnO NPs. Significant reductions in LDH level were noted for ZnO NPs at 300 mg/L concentration. The activity of antioxidant enzyme superoxide dismutase (SOD) significantly increased in the C. vulgaris exposed to 200mg/L and 300 mg/L ZnO NPs. The content of non-enzymatic antioxidant glutathione (GSH) significantly decreased in the groups with a ZnO NPs concentration of higher than 100mg/L. The level of lipid peroxidation (LPO) was found to increase as the ZnO NPs dose increased. The FT-IR analyses suggested surface chemical interaction between nanoparticles and algal cells. The substantial morphological changes and cell wall damage were confirmed through microscopic analyses (FESEM and CM).

Biosynthesis, characterization and cytotoxic effect of plant mediated silver nanoparticles using Morinda citrifolia root extract.

Silver has been used since time to control bodily infection, prevent food spoilage and heal wounds by preventing infection. The present study aims at an environmental friendly method of synthesizing silver nanoparticles, from the root of Morinda citrifolia; without involving chemical agents associated with environmental toxicity. The obtained nanoparticles were characterized by UV-vis absorption spectroscopy with an intense surface plasmon resonance band at 413 nm clearly reveals the formation of silver nanoparticles. Fourier transmission infra red spectroscopy (FTIR) showed nanopartilces were capped with plant compounds. Field emission-scanning electron microscopy (FE-SEM) and Transmission electron microscopy (TEM) showed that the spherical nature of the silver nanoparticles with a size of 30-55 nm. The X-ray diffraction spectrum XRD pattern clearly indicates that the silver nanoparticles formed in the present synthesis were crystalline in nature. In addition these biologically synthesized nanoparticles were also proved to exhibit excellent cytotoxic effect on HeLa cell.