scholarly journals Physicochemical transformation of ZnO and TiO2 nanoparticles in sea water and its impact on bacterial toxicity

2019 ◽  
Vol 6 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Asli Baysal ◽  
Hasan Saygin ◽  
Gul Sirin Ustabasi

Background: The enormous properties of metal oxide nanoparticles make it possible to use these nanoparticles in a wide range of products. As their usage and application continue to expand, environmental health concerns have been raised. In order to understand the behavior and effect of metal oxide nanoparticles in the environment, comprehensive and comparable physicochemical and toxicological data on the environmental matrix are required. However, the behavior and effect of nanoparticles in the real environmental matrix, e.g. sea water, are still unknown. Methods: In this study, the effects of zinc oxide (ZnO) and titanium dioxide (TiO2 ) nanoparticles on the bacteria (gram positive-Bacillus subtilis, Staphylococcus aureus/gram-negative Escherichia coli, and Pseudomonas aeruginosa) in sea water were investigated. Furthermore, to better understand the behavior of the toxicity, surface chemistry, sedimentation, dissolution, particle size, and zeta potential of the nanoparticles dispersed in the sea water matrices were investigated using Fourier-transform infrared spectrometry (FTIR), ultraviolet–visible (UV-VIS) spectrophotometry, graphite furnace atomic absorption spectrometer (GFAAS), and dynamic light scattering (DLS), respectively. Results: The environmental matrix had a significant influence on physicochemical behavior of the tested nanoparticles. Besides, the inhibition of tested bacteria was observed against ZnO and TiO2 nanoparticles in the presence of sea water, while there was no inhibition in the controlled condition. Conclusion: The results demonstrate that surface chemistry with exposure to the sea water can have a significant role on the physicochemical properties of nanoparticles and their toxicity.

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Alexandra Guerreiro ◽  
Nicholas Chatterton ◽  
Eleanor M. Crabb ◽  
Jon P. Golding

Abstract Background A wide range of nanoparticles (NPs), composed of different elements and their compounds, are being developed by several groups as possible radiosensitisers, with some already in clinical trials. However, no systematic experimental survey of the clinical X-ray radiosensitising potential of different element nanoparticles has been made. Here, we directly compare the irradiation-induced (10 Gy of 6-MV X-ray photon) production of hydroxyl radicals, superoxide anion radicals and singlet oxygen in aqueous solutions of the following metal oxide nanoparticles: Al2O3, SiO2, Sc2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, ZrO2, MoO3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb4O7, Dy2O3, Er2O3 and HfO2. We also examine DNA damage due to these NPs in unirradiated and irradiated conditions. Results Without any X-rays, several NPs produced more radicals than water alone. Thus, V2O5 NPs produced around 5-times more hydroxyl radicals and superoxide radicals. MnO2 NPs produced around 10-times more superoxide anions and Tb4O7 produced around 3-times more singlet oxygen. Lanthanides produce fewer hydroxyl radicals than water. Following irradiation, V2O5 NPs produced nearly 10-times more hydroxyl radicals than water. Changes in radical concentrations were determined by subtracting unirradiated values from irradiated values. These were then compared with irradiation-induced changes in water only. Irradiation-specific increases in hydroxyl radical were seen with most NPs, but these were only significantly above the values of water for V2O5, while the Lanthanides showed irradiation-specific decreases in hydroxyl radical, compared to water. Only TiO2 showed a trend of irradiation-specific increase in superoxides, while V2O5, MnO2, CoO, CuO, MoO3 and Tb4O7 all demonstrated significant irradiation-specific decreases in superoxide, compared to water. No irradiation-specific increases in singlet oxygen were seen, but V2O5, NiO, CuO, MoO3 and the lanthanides demonstrated irradiation-specific decreases in singlet oxygen, compared to water. MoO3 and CuO produced DNA damage in the absence of radiation, while the highest irradiation-specific DNA damage was observed with CuO. In contrast, MnO2, Fe3O4 and CoO were slightly protective against irradiation-induced DNA damage. Conclusions Beyond identifying promising metal oxide NP radiosensitisers and radioprotectors, our broad comparisons reveal unexpected differences that suggest the surface chemistry of NP radiosensitisers is an important criterion for their success.


2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Mohamed E. I. Badawy ◽  
Mahmoud A. M. El-Nouby ◽  
Abd El-Salam M. Marei

The present study aims to prepare two new types of chitosan-metal oxide nanoparticles (Ch-MO NPs), namely, chitosan-copper oxide nanoparticles (Ch-CuO NPs) and chitosan-zinc oxide nanoparticles (Ch-ZnO NPs), using sol-gel precipitation mechanism, and test them new as adsorbent materials for extraction and clean-up of different pesticides from water. The design of core-shell was implemented by metal oxide core with chitosan as a hard shell after crosslinking mechanism by glutaraldehyde and then epichlorohydrin. The characterizations of the prepared nanoparticles were investigated using Fourier transform infrared spectrometry (FT-IR), zeta potential, scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). FT-IR confirmed the interaction between chitosan, metal oxide, and crosslinking mechanism. SEM and TEM explained that the nanoparticles have a spherical morphology and nanosize of 93.74 and 97.95 nm for Ch-CuO NPs and Ch-ZnO NPs, respectively. Factorial experimental design was applied to study the effect of pH, concentration of pesticide, agitation time, and temperature on the efficiency of adsorption of pesticides from water samples. The results indicated that optimum conditions were pH of 7, temperature of 25°C, and agitation time of 25 min. The SPE cartridges were then packed with Ch-MO NPs, and seven pesticides of abamectin, diazinon, fenamiphos, imidacloprid, lambda-cyhalothrin, methomyl, and thiophanate-methyl were extracted from water samples and determined by HPLC. The extraction efficiency of Ch-ZnO NPs was higher than Ch-CuO NPs, but both removed a larger amount of most of tested pesticides than the standard ODS cartridge (C18). The results showed that this method achieves rapid and simple extraction in small quantities of adsorbents (Ch-MO NPs) and solvents. In addition, the method is highly sensitive to pesticides and has a high recovery rate.


2018 ◽  
Vol 24 (8) ◽  
pp. 896-903 ◽  
Author(s):  
Usha Kadiyala ◽  
Nicholas A. Kotov ◽  
J. Scott VanEpps

Metal oxide nanoparticles (MO-NPs) are known to effectively inhibit the growth of a wide range of Gram-positive and Gram-negative bacteria. They have emerged as promising candidates to challenge the rising global issue of antimicrobial resistance. However, a comprehensive understanding of their mechanism of action and identifying the most promising NP materials for future clinical translation remain a major challenge due to variations in NP preparation and testing methods. With various types of MO-NPs being rapidly developed, a robust, standardized, in vitro assessment protocol for evaluating the antibacterial potency and efficiency of these NPs is needed. Calculating the number of NPs that actively interact with each bacterial cell is critical for assessing the dose response for toxicity. Here we discuss methods to evaluate MO-NPs antibacterial efficiency with focus on issues related to NPs in these assays. We also highlight sources of experimental variability including NP preparation, initial bacterial concentration, bacterial strains tested, culture microenvironment, and reported dose.


Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1790 ◽  
Author(s):  
Ana Maria Diez-Pascual

Thermosetting polymers derived from vegetable oils (VOs) exhibit a wide range of outstanding properties that make them suitable for coatings, paints, adhesives, food packaging, and other industrial appliances. In addition, some of them show remarkable antimicrobial activity. Nonetheless, the antibacterial properties of these materials can be significantly improved via incorporation of very small amounts of metal oxide nanoparticles (MO-NPs) such as TiO2, ZnO, CuO, or Fe3O4. The antimicrobial efficiency of these NPs correlates with their structural properties like size, shape, and mainly on their concentration and degree of functionalization. Owing to their nanoscale dimensions, high specific surface area and tailorable surface chemistry, MO-NPs can discriminate bacterial cells from mammalian ones, offering long-term antibacterial action. MO-NPs provoke bacterial toxicity through generation of reactive oxygen species (ROS) that can target physical structures, metabolic paths, as well as DNA synthesis, thereby leading to cell decease. Furthermore, other modes of action—including lipid peroxidation, cell membrane lysis, redox reactions at the NP–cell interface, bacterial phagocytosis, etc.—have been reported. In this work, a brief description of current literature on the antimicrobial effect of VO-based thermosetting polymers incorporating MO-NPs is provided. Specifically, the preparation of the nanocomposites, their morphology, and antibacterial properties are comparatively discussed. A critical analysis of the current state-of-art on these nanomaterials improves our understanding to overcome antibiotic resistance and offers alternatives to struggle bacterial infections in public places.


2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Derek Fawcett ◽  
Jennifer J. Verduin ◽  
Monaliben Shah ◽  
Shashi B. Sharma ◽  
Gérrard Eddy Jai Poinern

Today there is a growing need to develop reliable, sustainable, and ecofriendly protocols for manufacturing a wide range of metal and metal oxide nanoparticles. The biogenic synthesis of nanoparticles via nanobiotechnology based techniques has the potential to deliver clean manufacturing technologies. These new clean technologies can significantly reduce environmental contamination and decease the hazards to human health resulting from the use of toxic chemicals and solvents currently used in conventional industrial fabrication processes. The largely unexplored marine environment that covers approximately 70% of the earth’s surface is home to many naturally occurring and renewable marine plants. The present review summarizes current research into the biogenic synthesis of metal and metal oxide nanoparticles via marine algae (commonly known as seaweeds) and seagrasses. Both groups of marine plants contain a wide variety of biologically active compounds and secondary metabolites that enables these plants to act as biological factories for the manufacture of metal and metal oxide nanoparticles.


Author(s):  
Sharadwata Pan ◽  
Thomas B. Goudoulas ◽  
Jaison Jeevanandam ◽  
Kei Xian Tan ◽  
Shamik Chowdhury ◽  
...  

Invention of novel nanomaterials guaranteeing enhanced biomedical performance in diagnostics and therapeutics, is a perpetual initiative. In this regard, the upsurge and widespread usage of nanoparticles is a ubiquitous phenomenon, focusing predominantly on the application of submicroscopic (< 100 nm) particles. While this is facilitated attributing to their wide range of benefits, a major challenge is to create and maintain a balance, by alleviating the associated toxicity levels. In this minireview, we collate and discuss particularly recent advancements in therapeutic applications of metal and metal oxide nanoparticles in skin and cosmetic applications. On the one hand, we outline the dermatological intrusions, including applications in wound healing. On the other hand, we keep track of the recent trends in the development of cosmeceuticals via nanoparticle engrossments. The dermato-cosmetic applications of metal and metal oxide nanoparticles encompass diverse aspects, including targeted, controlled drug release, and conferring ultraviolet and antimicrobial protections to the skin. Additionally, we deliberate on the critical aspects in comprehending the advantage of rheological assessments, while characterizing the nanoparticulate systems. As an illustration, we single out psoriasis, to capture and comment on the nanodermatology-based curative standpoints. Finally, we lay a broad outlook and examine the imminent prospects.


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