Synthesis of carboxymethyl chitosan-guar gum-poly(vinylpyrrolidone) ternary blended hydrogels with antibacterial/anticancer efficacy and drug delivery applications.

Biopolymers have the utmost significance in biomedical applications and blending synthetic polymers has shown favorable characteristics versus individual counterparts. The utilization of the blends can be restricted through the use of toxic chemical agents such as initiators or crosslinkers. In this regard, a chemical agent-free ionizing irradiation is a beneficial alternative for preparing the hydrogels for biomedical applications. In this study, carboxymethyl chitosan (CM-CS), guar gum (GG), and poly(vinylpyrrolidone) (PVP) based ternary blends (TB) were crosslinked using various doses of ionizing irradiation to fabricate hydrogels. The prepared hydrogels were characterized for physicochemical properties, swelling analysis, biological assays, and drug delivery applications. Swelling analysis in distilled water revealed that the hydrogels exhibit excellent swelling characteristics. An in vitro cytocompatibility assay showed that the hydrogels have greater than 90% cell viability for the human epithelial cell line and a decreasing cell viability trend for the human alveolar adenocarcinoma cell line. In addition, the prepared hydrogels possessed excellent antibacterial characteristics against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli). Finally, the release studies of anti-inflammatory Quercus acutissima (QA) loaded hydrogels exhibited more than 80% release in phosphate-buffered saline (pH = 7.4). These findings suggest that TB hydrogels can be used as suitable carrier media for different release systems and biomedical applications.

Removal of Radioactive Iodine Using Silver/Iron Oxide Composite Nanoadsorbents.

Efficient and cost-effective removal of radioactive iodine (radioiodine) from radioactive contaminated water has become a crucial task, following nuclear power plant disasters. Several materials for removing radioiodine have been reported in the literature. However, most of these materials exhibit some limitations, such as high production cost, slow adsorption kinetics, and poor adsorption capacity. Herein, we present silver/iron oxide nanocomposites (Ag/Fe3O4) for the efficient and specific removal of iodine anions from contaminated water. The Ag/Fe3O4 were synthesized using a modified method and characterized via scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analyses. This adsorbent showed a high adsorption capacity for iodine anions (847 mg/g of the adsorbent) in pure water. Next, Ag/Fe3O4 was applied to the removal of radioiodine, and high removal efficiencies were observed in water. In addition, its desalination capacity was retained in the presence of competitive ions and varied pH. After the adsorption process, Ag/Fe3O4 was easily removed from the water by applying an external magnetic field. Moreover, the same operation can be repeated several times without a significant decrease in the performance of Ag/Fe3O4. Therefore, it is expected that the findings presented in this study will offer a new method for desalinating radioiodine in various aqueous media.

Effect of Varying Amount of Polyethylene Glycol (PEG-600) and 3-Aminopropyltriethoxysilane on the Properties of Chitosan based Reverse Osmosis Membranes.

Chitosan and polyethylene glycol (PEG-600) membranes were synthesized and crosslinked with 3-aminopropyltriethoxysilane (APTES). The main purpose of this research work is to synthesize RO membranes which can be used to provide desalinated water for drinking, industrial and agricultural purposes. Hydrogen bonding between chitosan and PEG was confirmed by displacement of the hydroxyl absorption peak at 3237 cm-1 in pure chitosan to lower values in crosslinked membranes by using FTIR. Dynamic mechanical analysis revealed that PEG lowers Tg of the modified membranes vs. pure chitosan from 128.5 °C in control to 120 °C in CS-PEG5. SEM results highlighted porous and anisotropic structure of crosslinked membranes. As the amount of PEG was increased, hydrophilicity of membranes was increased and water absorption increased up to a maximum of 67.34%. Permeation data showed that flux and salt rejection value of the modified membranes was increased up to a maximum of 80% and 40.4%, respectively. Modified films have antibacterial properties against Escherichia coli as compared to control membranes.

Synthesis and characterization of hydrogels based on carboxymethyl chitosan and poly(vinylpyrrolidone) blends prepared by electron beam irradiation having anticancer efficacy, and applications as drug carrier for controlled release of drug.

Herein, carboxymethyl chitosan and poly(vinylpyrrolidone) based hydrogels were synthesized by electron beam irradiation with dose variations (15 kGy, 30 kGy, and 45 kGy) for drug delivery applications. Irradiation crosslinked hydrogels were characterized for swellings in different medias, chemical, thermal, cell cytotoxicity, and drug release aspects. Swelling analysis was evaluated in distilled water, buffer, and saline solutions. Fourier transform infrared analysis revealed the establishment of physical interactions and confirmed the presence of functional groups present in the drug carriers. Scanning electron microscopy depicted the porous structure, which is responsible for swelling, drug loading, and release. Cell cytotoxicity assays indicated good cell viability on RAW 264.7 cells and anticancer activity on cancerous AGS cell lines. Cumulative drug release (%) of kanamycin in PBS at pH 7.4 was more than 90 % at 168 h. These drug carriers show promise to be developed as a sustained drug delivery system.

Novel Maleic Acid, Crosslinked, Nanofibrous Chitosan/Poly (Vinylpyrrolidone) Membranes for Reverse Osmosis Desalination.

Fresh and clean water is consistently depleting and becoming a serious problem with rapid increases in population, so seawater desalination technology has captured global attention. For an efficient desalination process, this work proposes a novel, nanofibrous, thin-film composite membrane (NF-TFC) based on the deposition of the nanofibrous active layer of a blend of chitosan (CS) and poly (vinylpyrrolidone) (PVP) crosslinked with maleic acid on a 3-triethoxysilylpropylamine functionalized cellulose acetate substrate. FTIR analysis demonstrated the development of chemical and physical interactions and confirmed the incorporation of functional groups present in the NF-TFC. Scanning electron microscopy (SEM) micrographs depict the fibrous structure of the active layers. The reverse osmosis (RO) desalination characteristics of NF-TFC membranes are elevated by increasing the concentration of the crosslinker in a CS/PVP blend. Cellulose acetate (CA)-S4 attained an optimal salt rejection of 98.3% and permeation flux of 42.9 L/m2h, suggesting that the NF-TFC membranes could be favorable for seawater desalination.