Role of physical and chemical interactions in the antibacterial behavior of ZnO nanoparticles against E. coli.

Zinc oxide (ZnO) nanoparticles (NPs) exhibit antibacterial activity against both Gram-positive and Gram-negative bacteria. However, the antimicrobial mechanism of ZnO NPs remains unclear. In this study, we investigated the interactions among ZnO NPs, released chemicals (Zn(2+) and Reactive Oxygen Species, ROS) and Escherichia coli (E. coli) cells. ZnO NPs without contacting with bacterial cells showed strong antibacterial effect. The results of the leakage of intracellular K(+) and integrity of carboxyfluoresce in-filled liposomes showed that ZnO NPs have antimicrobial activity against E. coli by non-specifically disrupting E. coli membranes. Traces of zinc ions (1.25mg/L) and hydrogen peroxide (from 1.25 to 4.5μM/L) were detected in ZnO NPs suspensions, but was insufficient to cause the antibacterial effect. However, the addition of radical scavengers suppressed the bactericidal effect of ZnO coated films against E. coli, potentially implicating ROS generation, especially hydroxyl radicals, in the antibacterial ability of ZnO NPs

Attaching different kinds of proteinaceous nanospheres to a variety of fabrics using ultrasound radiation

The application of a rapid, non-destructive, cost-effective technique such as ultrasonic emulsification for the coating of different textiles was explored. The technical benefits for this research were the generation of multifunctional materials and their combinations through environmentally friendly processing technologies. We have shown for the first time that ultrasonic waves can be used to coat proteinaceous micro- and nanospheres (PM) of BSA (Bovine Serum Albumin) protein and casein on the surface of cotton and polyester (PE) fabrics. The creation and the anchoring of the microbubbles to the fabrics were performed by a one step reaction, and the process is usually stopped after 3 min. The PM of bovine serum albumin (BSA) bonded to cotton and polyester fabrics has shown stability for ~9 months. The PMs were shown to be attached more strongly to the polyester than to the cotton, and sustained stronger washing conditions on PE. The diameter of the BSA and the casein spheres on cotton was in the range of 0.8–1.0 µm, while on the PE it varied between 60 and 120 nm.This research, was carried out as part of the activities of the LIDWINE Consortium, Contract No NMP2-CT-2006-026741 LIDWINE is an IP Project of the 6th EC Progra

Zinc oxide nanoparticle-coated films: fabrication, characterization, and antibacterial properties

In this article, novel antibacterial PVC-based films coated with ZnO nanoparticles (NPs) were fabricated, characterized, and studied for their antibacterial properties. It was shown that the ZnO NPs were coated on the surface of the PVC films uniformly and that the coating process did not affect the size and shape of the NPs on the surface of PVC films. Films coated with concentrations of either 0.2 or 0.075 g/L of ZnO NPs exhibited antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, but exhibited no antifungal activity against Aspergillus flavus and Penicillium citrinum. Smaller particles (100 nm) exhibited more potent antibacterial activity than larger particles (1000 nm). All ZnO-coated films maintained antibacterial activity after 30 days in water

Tuning the Properties of ZnO, Hematite, and Ag Nanoparticles by Adjusting the Surface Charge

Nanomaterials have become a central focus of scientific research and technological development over the last decade due to their broad applications in a variety of physicochemical and biological fields, including lasers,[1] solar cells,[2] catalysts,[3] sensors,[4–6] biological labels,[7] drug delivery,[8,9] and cancer therapy.[10–13] Controlling the size and/or shape of nanoparticles (NPs) has been widely used to modify and improve NP properties for designated applications.[1,6,11,14–19] Recently, it has been found that adjusting the surface charge (SC) can be a effective method to modify the cytotoxicity, cellular uptake, and specificity of targeting of NPs.[9,10,12,20–22] Electrons and/or other electrical charges play an essential role in many key material properties, such as electrostatic interactions, photoluminescence (PL), magnetism, plasmon properties, chemical bonds, and related chemical properties

Decorating parylene-coated glass with ZnO nanoparticles for antibacterial applications : a comparatives study of sonochemical, microwave, and microwave-plasma coating routes

A glass substrate, coated with a Parylene film, was coated with ZnO by three different methods: ultrasound, microwave, and microwave-plasma irradiation. These coating modes are simple, efficient, and environmentally friendly one-step processes. The structure of the coated products was characterized and compared using methods such as XRD, HR-SEM, EDS, RBS, and optical spectroscopy. Coating by ZnO nanoparticles was achieved for all three approaches. The products were found to differ in their particle sizes, coating thickness, and depth of penetration. All of the ZnO−Parylene−glass composites demonstrated a significant antibacterial activity against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) strains