Bio-approach: Ureolytic bacteria mediated synthesis of ZnO nanocrystals on cotton fabric and evaluation of their antibacterial properties

Dye adsorption and bactericidal properties of TiO2/chitosan coating layer

A new kind of titanium oxide dispersed in chitosan (TiO2/CS) nanocomposite adsorbent was prepared and adhered to high surface area substrate, cellulose microfibers mat (CMM). CS-CMM and TiO2/CS-CMM were used for the thymol violet (TV) dye removal from wastewater. Characterization of materials was carried out by X-ray diffraction, scanning electron microscope and energy dispersive X-ray spectroscopy. The adsorption properties of both the CS-CMM and TiO2/CS-CMM were investigated as a function of adsorbent dosage, solution pH, and contact time. It was revealed that the composites pretreated in the solution with higher pH value exhibited larger adsorption capacities. Kinetic studies showed that the composites could adsorb TV dye rapidly and reached the equilibrium in 90min. The adsorption process followed pseudo-second order kinetics and involved particle diffusion mechanism. The calculated maximum adsorption capacities of CS-CMM and TiO2/CS-CMM were 84.32 and 97.51mgg(-1), respectively. Compare to CS, the TiO2/CS nanocomposite coated CMM showed higher antibacterial characteristics as tested against Escherichia coli.

Enhancement of bioactivity of titanium carbonitride nanocomposite thin films on steels with biosynthesized hydroxyapatite

Thin films of titanium carbonitride (TiCN) were fabricated by DC magnetron sputtering on medical grade steel. The biocompatibility of the coating was further enhanced by growing hydroxyapatite crystals over the TiCN-coated substrates using biologically activated ammonia from synthetic urine. The coatings were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM)-energy dispersive spectroscopy, and Raman spectroscopy. The electrochemical behavior of the coatings was determined in simulated body fluid. In addition, hemocompatibility was assessed by monitoring the attachment of platelets on the coating using SEM. The wettability of the coatings was measured in order to correlate with biocompatibility results. Formation of a coating with granular morphology and the preferred orientation was confirmed by SEM and X-ray diffraction results. The hydroxyapatite coating led to a decrease in thrombogenicity, resulting in controlled blood clot formation, hence demonstrating the hemocompatibility of the coating.

PEGylation of novel hydroxyapatite/PEG/Ag nanocomposite particles to improve its antibacterial efficacy

Hydroxyapatite (HAp) nanocomposite particles were prepared simply in the presence of polyethylene glycol (PEG) and fabricated with silver via a sol-gel route and the physico-chemical and biological properties of these materials were investigated. The objective of this study is to inspect the crystallinity and antibacterial activity of these composite materials. PEG has been used to greatly promote biocompatibility and biodegradability of HAp. Silver nanoparticles were used for improving its bactericidal efficacy while applying composites. Nano-sized HAp composite particles with PEG and nano-silver was incorporated to increase the crystalline nature of the nanocomposite. The structure of nanocomposite particles was studied by XRD, FTIR, HR-SEM, EDS and TEM analyses. Silver nanoparticles loaded on the synthesized HAp-PEG showed a synergistic antibacterial effect against Gram-negative bacterium Escherichia coli (E. coli). The controlled release of Ag(+) ion from HAp-PEG-Ag nanocomposite has given good antibacterial efficacy evidenced by epi-fluorescence microscopy images during different hours.

RETRACTED: Facile, eco-friendly and template free photosynthesis of cauliflower like ZnO nanoparticles using leaf extract of Tamarindus indica (L.) and its biological evolution of antibacterial and antifungal activities

In the present investigation, we chose the very simple and eco-friendly chemical method for synthesis of zinc oxide nanoparticles from leaf extract of Tamarindus indica (L.) (T. indica) and developed the new green route for synthesis of nanoparticles. Formed product has been studied by UV-vis absorption spectroscopy, Photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FE-SEM) and with corresponding energy dispersive X-ray analysis (EDX). Mainly, the present results depicted that the synthesized nanoproducts are moderately stable, hexagonal phase, roughly spherical with maximum particles in size range within 19-37 nm in diameter. The antibacterial and fungal activities of aqueous extracts of T. indica were ended with corresponding disk diffusion and Minimum Inhibitory Concentration (MIC). The highest mean zones of inhibition were observed in the ZnO NPs (200 μg/mL) against Staphylococcus aureus (13.1±0.28). Finally, it can be concluded that microbial activity of ZnO NPs has more susceptible S. aureus than the other micro organisms. Further, the present investigation suggests that ZnO NPs has the potential applications for various medical and industrial fields.

Surface activation of cotton fiber by seeding silver nanoparticles and in situ synthesizing ZnO nanoparticles

Photocatalytic and antibacterial cotton fabric was produced by an in situ synthesis of zinc oxide–silver nanocomposites.