Control of the biomaterial properties through stimuli-responsive polymeric platforms has become an essential technique in recent biomedical applications. A multilayer system of thiolated chitosan (t-Chi) and thiolated chondroitin sulfate (t-CS), consisting of five double layers ([t-Chi/t-CS]), was fabricated here by applying a layer-by-layer coating strategy. To represent a novel class of chemically tunable nanostructures, the ability to cross-link pendant thiol groups was tested by a rise from pH 4 during layer formation to pH 9.3 and a more powerful chemical stimulus by using chloramine-T (ChT). Following both treatments, the resulting multilayers showed stimuli-dependent behavior, as demonstrated by their content of free thiols, wettability, surface charge, elastic modulus, roughness, topography, thickness, and binding of fibronectin. Studies with human dermal fibroblasts further demonstrated the favorable potential of the ChT-responsive multilayers as a cell-adhesive surface compared to pH-induced cross-linking. Because the [t-Chi/t-CS] multilayer system is responsive to stimuli such as the pH and redox environment, multilayer systems with disulfide bond formation may help to tailor their interaction with cells, film degradation, and controlled release of bioactive substances like growth factors in a stimuli-responsive manner useful in future wound healing and tissue engineering applications.
Nanoformulations derived from fine porous ZnO quantum dot nanoparticles (QD NPs) can offer strong potential medical applications; especially in cancer therapy. ZnO QD NPs was synthesized by sol-gel hydrothermal process, fast cold quenching and further smart surface functionalization methods to obtain ultrasmall size (1-4 nm) NPs. ZnO nanopolymer, a wetting agent, PEG co-solvent and water/oil emulsion stabilizer were considered in our nanofluid formulation. The resulting nanofluid was characterized by SEM, FTIR, photoluminescence, band gap energy, zeta potential and UV-Vis spectroscopy. The cytotoxic effects on the growth of four cancer cell lines were evaluated by MTT assay. The IC (µg/ml) values of 30, 41, 40 and 35 for KB44, MCF-7, HT29 and HeLa cells, respectively, after 48 h of nanoformulation treatment suggested the cytotoxic effect of this nanoformulation on these cell lines in a concentration-dependent manner (p < .05). ZnO nanofluid destroyed cancer cell lines more efficiently than the normal HFF-2 (IC= 105 µg/ml). The reduction in cell viability in response to ZnO nanofluid treatment induced apoptosis in the cultured cells. Skin sensitization test plus antibacterial activity were also measured. Side effect tests on 70 white mice in vivo resulted in only 3-4 abnormal situations in hepatic tissue section possibly due to the idiosyncratic drug reactions.
Antibacterial activities of various spherical zinc oxide nanoparticles and nano special morphological structures including quantum dots, nanorod arrays, nanoporous shapes and needle-like crystals had been investigated as new nanomedicine compounds. Also antibacterial activity based on minimal inhibitory concentration and the growth inhibitory zone (well method) was evaluated. ZnO nanostructures were fabricated by novel hydrolysis sol-gel-hydrothermal process followed with rapid quenching as new technique using glycerine, vegetable fatty esters such as coconut, sunflower and Lauric alcohol ethoxylated as organic templates soluble in eco-friendly nanofluids. The results showed that Bacillus anthracis and Pseudomonas aerogenes were extremely sensitive to treatment with unique ZnO nanostructured. Their growth inhibitory zone presented 30 mm and 25 mm inhibition zone with better inhibitory effect compared to the Gentamicin antibiotic standard. ZnO nanostructures had also been indicated to have a wide range of antibacterial activities against both Gram-positive and Gram-negative bacteria especially more effective on (gr+) species using the growth inhibitory zone. We could design and make significant formulations of fatty acids and esters-capped ZnO quantum dots nanofluids which created high promising agents for controlling Anthrax, Staphylococcus epidermidis and their influences in antimicrobial properties with low cost for future.
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