ABSTRACT
In this work, a pH-sensitive and antibacterial drug delivery system based on poly(vinyl alcohol) (PVA)/citric acid (CA)/Ag nanoparticles (NPs) was designed using a completely green, facile and one-step route. Interestingly, the crosslinking of PVA with CA, and in-situ formation of Ag NPs within the polymeric matrix were simultaneously and simply carried out using an annealing process without need for any toxic chemicals. The developed hydrogels were characterized by FTIR, UV-vis spectra, SEM and TEM techniques. It was found that CA not only acted as a crosslinker of PVA via esterification reaction, but also it endowed pH-responsiveness and antibacterial activity to the PVA matrix due to presence of free carboxylic acid groups on CA. Hydrogels demonstrated a pH-dependent swelling as well as drug release behavior, as the swelling ratio and the drug release at pH 7.4 were found higher than pH 1.2. Furthermore, the release of ciprofloxacin was more sustained when Ag NPs were incorporated into hydrogels. In addition, the incorporation of CA, Ag NPs and ciprofloxacin into the PVA matrix provided an effective antibacterial activity against E. coli and S. aureus microorganisms. The developed hydrogels can be considered as a promising material in the prolonged antibiotic therapy such as intestinal infection treatment.
Subject(s)
Anti-Bacterial Agents/pharmacology , Ciprofloxacin/pharmacology , Cross-Linking Reagents/pharmacology , Escherichia coli/drug effects , Staphylococcus aureus/drug effects , Anti-Bacterial Agents/chemistry , Ciprofloxacin/chemistry , Citric Acid/chemistry , Citric Acid/pharmacology , Cross-Linking Reagents/chemistry , Drug Delivery Systems , Drug Liberation , Hydrogels/chemical synthesis , Hydrogels/chemistry , Hydrogels/pharmacology , Hydrogen-Ion Concentration , Metal Nanoparticles/chemistry , Microbial Sensitivity Tests , Particle Size , Polyvinyl Alcohol/chemistry , Polyvinyl Alcohol/pharmacology , Silver/chemistry , Silver/pharmacology , Surface PropertiesABSTRACT
A novel Fe(III) crosslinked poly (vinyl alcohol) (PVA)/chitin nanofiber composites were prepared for dye adsorption from water. The adsorbents were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis. The effects of Fe(III) content and chitin nanofibers (NFs) incorporation on the dye removal efficiency of adsorbents were investigated. The adsorption influencing parameters such as solution pH, contact time and initial dye concentration were optimized for maximum methyl orange (MO) adsorption. With loading of chitin NFs, the dye removal efficiency of PVA/Fe(III) adsorbents was noticeable increased. In addition, the dye removal efficiency did not show significant decline in alkaline solution in the presence of chitin NFs. Kinetics, isotherms and thermodynamics of dye adsorption process were also thoroughly studied. The adsorption data were better fitted with the pseudo-second-order kinetics and Freundlich isotherm model. PVA-chitin NFs-Fe(III) adsorbent exhibited a high maximum adsorption capacity of 810.4â¯mg/g for MO adsorption. Furthermore, reuse experiments revealed that the adsorption efficiency remained almost constant during five cycles of adsorption/desorption. At last, the possible mechanism for dye adsorption-desorption was proposed. The obtained results revealed that the developed bionanocomposites could be considered as promising recyclable adsorbents for wastewater treatment.
