Pyridine and isoxazole substituted 3-formylindole-based chitosan Schiff base polymer: Antimicrobial, antioxidant and in vitro cytotoxicity studies on THP-1 cells.

This paper presents the synthesis of two new chitosan Schiff base (CSB) polymers, namely, 2PCT and 4MCT based on pyridin-2-ylmethyl-1H-indole-3-carbaldehyde and 1-(4-methyl-3,5-dimethylisoxazole)-1H-indole-3-carbaldehyde with chitosan (CT). The structural features of CSB polymers were confirmed by Fourier-transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy and their antimicrobial activity was evaluated against Staphylococcus aureus, Escherichia coli and Candida albicans. The antioxidant studies found that both 2PCT and 4MCT presented significant free radical scavenging activity with IC50 at 169.01 and 372.84 µg/mL, respectively. The cell viability results obtained from in vitro cytotoxicity studies performed using human monocyte leukemia (THP-1) cells were found to be 75.6 ± 0.25 % and 79.1 ± 1.5 % for 2PCT and 4MCT, respectively, at a concentration of 10 mg/mL. Flow cytometry analysis demonstrated the reducing ability of CSB polymers on intracellular reactive oxygen species (ROS) in THP-1 cells. The overall results of antioxidant activity, in vitro biocompatibility and ability to reduce the intracellular ROS production emphasized that the CSB polymers prepared could serve as a potential biomaterial in biomedical applications, such as wound treatment process.

3-Formylindole-based chitosan Schiff base polymer: Antioxidant and in vitro cytotoxicity studies on THP-1 cells.

Two imine derivatives of chitosan (i-CTs), namely 2FCT and 5MCT, were synthesized by reacting chitosan (CT) with 2-(3-formyl-1H-indol-1yl)acetonitrile (2F), and 5-methoxyindole-3-carbaldehyde (5M), respectively. The antimicrobial evaluation of i-CTs exhibited stronger inhibition effect against Staphylococcus aureus, Escherichia coli and Candida albicans. The antioxidant activity of 2FCT and 5MCT showed strong scavenging ability with IC50 2.31 and 6.92 µg/mL, respectively. The results of in vitro cytotoxicity of 2FCT and 5MCT examined using human monocyte leukemia (THP-1) cells indicate no cytotoxic effect on host cells and the value of cell viability was found to be 87.08 and 84.47%, respectively. Measurement of intracellular Reactive Oxygen Species (ROS) production by flow cytometry analysis revealed that the 2FCT and 5MCT reduced the ROS generation by 83 and 43%, respectively. In summary, these findings show that i-CTs synthesized to be promising biomaterial for biomedical applications such as wound healing.

Green synthesis, characterization and drug delivery applications of a novel silver/carboxymethylcellulose - poly(acrylamide) hydrogel nanocomposite.

Biodegradable polymeric hydrogels are a unique class of macromolecular networks that can hold a large fraction of an aqueous solvent within their structures. They are particularly suitable for biomedical applications including controlled drug delivery, because of their ability to stimulate biological tissues. Many hydrogel-based networks have been designed and fabricated to meet the needs of pharmaceutical and medical fields. The investigation deals with the environment friendly synthesis of biodegradable semi interpenetrating hydrogel networks based on cross-linked poly(acrylamide) through an optimized rapid redox solution polymerization with N, N'Methylenebisacrylamide (MBA) in presence of Carboxymethylcellulose (CMC).The silver nanoparticles within hydrogel networks as nano reactors have been prepared by green synthesis via insitu reduction of silver nitrate (AgNO3) using Azadirachta Indica (Neem) plant extract under atmospheric conditions. The synthesized nanocomposites were characterised by FTIR spectroscopy, UV-Visible Spectroscopy, Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM) and Dynamic light scattering (DLS) technique. The thermal properties of the nanocomposite was analyzed by Thermogravimetric Analysis (TGA). The pH response and drug release profile of the synthesised biodegradable Silver-Hydrogel nanocomposite was investigated. Further, it was observed that physicochemical interaction between the polymeric nanocomposites and drug influences the degree of matrix swelling and therefore, its porosity and diffusion release process.