Distribution Of Zinc Oxide Nanoparticles Research Articles

Active and intelligent packaging films based on PVA/Chitosan/Zinc oxide nanoparticles/Sweet purple potato extract as pH sensing and antibacterial wraps

With growing concerns about the environmental impact of petroleum-based products, researchers are exploring new materials for food packaging. One promising avenue is the use of nanotechnology and natural materials. In this study, active and intelligent composite films were developed by solvent casting method using polyvinyl alcohol (P), chitosan (C), zinc oxide nanoparticles (Z), and sweet purple potato extract (S). The results demonstrated that C and Z did not affect the pH-based structural transformation of pigment (S)-containing PVA solutions. SEM microstructural observation revealed a uniform distribution of zinc oxide nanoparticles in the polymeric matrix. The addition of C and Z to the composite film improved its thermal, water barrier, and antibacterial and antioxidant properties. The tensile strength of the neat film (P) was 13.0 MPa and increased to 30.8 MPa for PCZS composite film because of the good interaction between PVA and the additives. The strong antimicrobial activity of PCZS composite films against environmental pathogens was validated by antimicrobial barrier analysis. Additionally, the functional composite film (PCZS) efficiently detected chicken freshness as a function of pH change. These findings suggest that the PCZS film has great potential as a smart and active food packaging material or as an antimicrobial wrap.

Toxicity and tolerance mechanism of binary zinc oxide nanoparticles and tetrabromobisphenol A regulated by humic acid in Chlorella vulgaris.

Recent studies have reported that nanoparticles (NPs) released into the aquatic environment may interact with persistent organic pollutants such as brominated flame retardants, whereas the environmental processes and toxicological impacts induced by such binary NPs require further specification. This study investigated the ultrastructural damage of Chlorella vulgaris triggered by exposure to zinc oxide (ZnO) NPs, tetrabromobisphenol A (TBBPA), ZnO-TBBPA, and ZnO-TBBPA-humic acid (HA), clarified the uptake and distribution of ZnO NPs in cells, and explored the physiological toxicity and tolerance mechanism. The results demonstrated that ZnO NPs induced irregular morphology in algal cells, and the disruption of the cellular ultrastructure by binary ZnO-TBBPA was also extremely severe due to the excessive uptake of ZnO NPs, which resulted in strong oxidative stress responses. In particular, the accumulation of reactive oxygen species further exacerbated the reduction of total chlorophyll content and algal density. Moreover, the cluster heat map and correlation analysis revealed that superoxide dismutase activity played a critical role in alleviating lipid peroxidation damage and enhancing the tolerance of algal cells to the stress of binary ZnO NPs. More notably, the existence of HA intensified the dispersion stability of NP suspensions and significantly mitigated the synergistic toxicity of binary ZnO-TBBPA. This study provides new insights into the environmental behavior and biological impacts of binary NPs in the natural environment.

Synthesis and characterization of PVDF/PMMA/ZnO hybrid nanocomposite thin films for humidity sensor application

This work aimed PVDF/PMMA thin films in a range of ZnO NPs weight ratios that were successfully manufactured via spin coating as high-performance humidity sensors. The films have been characterized to calculate the structure, functional groups, transmittance and optical energy band gap. X-ray diffraction (XRD) structural studies reveal that the prepared films are polycrystalline with hexagonal crystal structures. It was found that the grain size of these films decreases with the increasing weight ratios of zinc oxide nanoparticles. Field emission scanning electron microscopy reveals the homogeneous distribution of zinc oxide nanoparticles in the PMMA/PVDF matrix. EDX was used to investigate the chemical composition of the PVDF/PMMA/ZnO nanocomposite. FTIR test was performed to identify the functional groups in the prepared samples as well as the detection of doping which is added to the samples. The optical energy band gap values were calculated and types of optical transmission and absorption of the films were determined from the optical transmittance spectra. The optical absorption studies in the wavelength range (200−700) nm show that energy band gap values of the prepared films decrease from (4.98–4.28) eV with increasing the ZnO NPs weight ratio. A sensor for relative humidity within the range (31−100) % RH was manufactured by studying the change of electrical properties (capacitive, resistance) and simulating them theoretically. It was found that the PVDF/PMMA/ZnO NPs nanocomposite is highly sensitive to humidity due to the high porosity of the material. The parameters of the sensors, such as response time and retrieval time, were also studied, and it was found that the manufactured sensors have acceptable values for these parameters.

A novel antimicrobial ZnO nanoparticles-added polysaccharide edible coating for the preservation of postharvest avocado under ambient conditions

Edible coatings or films are considered effective and sustainable in preventing the waste of millions of tons of fruits and vegetables resulting from decay and deterioration. In this study, we propose a new edible coating formulation to preserve avocado. The edible coating consisted of film-forming mixed polysaccharides (chitosan and gum arabic) supplemented with non-toxic zinc oxide (ZnO) nanoparticles using the mixing method. ZnO nanoparticles with diameters ranging from 10 to 40 nm were synthesized using hydrothermal method. The prepared ZnO and ZnO/chitosan/gum arabic edible coatings were characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The results showed that the edible film coated on the avocado's surface was smooth and uniform with an even distribution of ZnO nanoparticles in the film matrix. The physicochemical properties of avocados, such as appearance and brightness; weight; firmness; and reducing sugar content significantly improved after coating with the ZnO/chitosan/gum arabic edible film as compared to the uncoated samples. The best protective performance was achieved when the coating’s optimum ZnO concentration was 0.3 % w/w. While the uncoated avocados rotted after seven days of storage in room temperature, the coated avocados remained fresh under similar storage conditions.

Diverse-shaped ZnO nanoparticles on polyester fabric through assorted in situ methods: studying plasma treatment order and different alkali media

Zinc oxide nanoparticles (ZnO-NPs) were in situ synthesized on the polyester fabric with different alkaline and plasma treatment orders. Diverse alkaline in various percentages along with different plasma orders were taken into account for synthesis of ZnO-NPs on the fabric at 130 °C for 1 h. In general, applying NaOH as an alkaline in synthesis of ZnO-NPs on polyester made the smallest ZnO-NPs with uniform distribution. Also, air plasma pre-treatment activated the surface of polyester fabric affected the shape of nanoparticles. The ZnO-NPs on the air plasma pre-treated fabric led to the even distribution of nanoparticles on the surface, while the plasma post-treatment caused the uneven nanoparticles distribution on the surface. The polyester/ZnO-NPs fabric were characterized by several techniques, including field-emission scanning electron microscopy (FESEM), EDS, and MAP analysis. The size, shape, and distribution of ZnO-NPs on the polyester fabric varied in each condition. Further, treatment with urea along with NaOH resulted in the smaller ZnO nanoparticles with better distribution of NPs.

Zinc Oxide Nanoparticle Induces Apoptosis in Human Epidermoid Carcinoma Cells Through Reactive Oxygen Species and DNA Degradation.

Zinc oxide nanoparticles (ZnO-NPs) are used immensely in technology and medicine, but very less is known about toxicity mechanism to human epidermal cells. The objective of this study was to evaluate possible anticancer properties of ZnO-NPs on human epidermoid carcinoma cells using MTT assay, measurement of reactive oxygen species, DNA fragmentation, and nuclear condensation. ZnO-NPs were synthesized by sol-gel method using zinc acetate dihydrate, ethylene glycol, and 2-propyl alcohol. Numerous characterization techniques such as UV-visible spectroscopy, X-ray powder diffraction, transmission electron microscopy, and dynamic light scattering spectroscopy were used to confirm synthesis, purity, optical, and surface characteristics, size, shape, and distribution of ZnO-NPs. Our finding showed that ZnO-NPs considerably decreased cell viability of human epidermoid carcinoma A431 cells with a parallel increase in nuclear condensation and DNA fragmentation in a dose dependent manner. Moreover, real time PCR expression study showed that treatment of human epidermoid carcinoma cells with ZnO-NPs trigger increased expression of tumor suppressor gene p53, bax, and caspase-3 while downregulate antiapoptotic gene bcl-2. Thus ZnO-NPs induce apoptosis in A431 cells through DNA degradation and generation of reactive oxygen species via p53, bax/bcl-2, and caspase pathways.

Distribution of zinc oxide nanoparticles on unbleached and bleached bamboo paper via in-situ approaches

Metal oxide nanoparticles such as zinc oxide are increasingly being recognized for potential use in research and health-related application. It is usually incorporated in the modern healthcare products functioning as antimicrobial properties. These inorganic compounds could be applied for antimicrobial paper. Therefore, the objective of this study is to investigate the growth distribution of zinc oxide nanoparticles prepared via in-situ approaches on unbleached and bleached pulps. In order to produce these pulps, hydrothermal method is used throughout the study. The micrograph obtained from the scanning of Field Emission Scanning Electron Microscope exhibited that zinc oxide nanoparticles appeared in the range of 64.1 nm to 87.5 nm supported by the analysis of Field Emission Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis, as high as 27% zinc and 39% oxygen. As expected, zinc oxide nanoparticles decreased the mechanical properties of paper due to the interference of fiber bonding. Antimicrobial test demonstrated acceptable results which required further test.

Imparting superhydrophobic and antibacterial properties onto the cotton fabrics: synergistic effect of zinc oxide nanoparticles and octadecanethiol

In this research, a one-step method for the preparation of superhydrophobic and antibacterial cotton fabric is presented, which has been modified by zinc oxide (ZnO) nanoparticles and octadecanethiol (ODT). The individual use of ZnO and ODT resulted in superhydrophilic fabrics whereas their combined use caused a transformation to the superhydrophobic behavior. Based on the morphological analysis, the distribution of ZnO nanoparticles on the fabrics’ surfaces was notably improved leading to a much more uniform rough structure. Such proper level of roughness along with the hydrophobicity induced by ODT were found responsible for the observed high contact angle (161°). The deposition of ZnO and ODT on the fabrics’ surfaces was further proved by X-ray photoelectron spectroscopy. The bacterial adhesion experiments revealed that even the sole presence of ODT could notably reduce the bacterial attachment to the fabric due to the reduced surface free energy. The individual use of ZnO nanoparticles was found to have a strong antibacterial effect on both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. The bacterial adhesion was even further diminished upon the combined use of ZnO and ODT. The numbers of adhered S. aureus and E. coli cells were highly reduced from 438,000 and 192,000 CFU cm−2 for the pristine fabric to 600 and 48 CFU cm−2 for the superhydrophobic fabric, respectively. Simultaneous achievement of superhydrophobicity and antibacterial activity on the fabrics’ surfaces could have promising potential in the hospital garments and facemasks where patients and staff need to be protected from the infections.

Comparison of the effects and distribution of zinc oxide nanoparticles and zinc ions in activated sludge reactors

ABSTRACTZinc Oxide nanoparticles (ZnO NPs) are being increasingly applied in the industry, which results inevitably in the release of these materials into the hydrosphere. In this study, simulated waste-activated sludge experiments were conducted to investigate the effects of Zinc Oxide NPs and to compare it with its ionic counterpart (as ZnSO4). It was found that even 1 mg/L of ZnO NPs could have a small impact on COD and ammonia removal. Under 1, 10 and 50 mg/L of ZnO NP exposure, the Chemical Oxygen Demand (COD) removal efficiencies decreased from 79.8% to 78.9%, 72.7% and 65.7%, respectively. The corresponding ammonium (NH4+ N) concentration in the effluent significantly (P < 0.05) increased from 11.9 mg/L (control) to 15.3, 20.9 and 28.5 mg/L, respectively. Under equal Zn concentration, zinc ions were more toxic towards microorganisms compared to ZnO NPs. Under 50 mg/L exposure, the effluent Zn level was 5.69 mg/L, implying that ZnO NPs have a strong affinity for activated sludge. The capacity for adsorption of ZnO NPs onto activated sludge was found to be 2.3, 6.3, and 13.9 mg/g MLSS at influent ZnO NP concentrations of 1.0, 10 and 50 mg/L respectively, which were 1.74-, 2.13- and 2.05-fold more than under Zn ion exposure.

Zinc oxide nanoparticle induced age dependent immunotoxicity in BALB/c mice.

Zinc oxide (ZnO) nanoparticles (NPs) have potential applications in cosmetics, food packaging and biomedicine but concerns regarding their safety need to be addressed. In the present study, the immunotoxic potential of ZnO NPs was evaluated in different ages of BALB/c mice after sub-acute exposure. The cytokine release, immunophenotyping, distribution of ZnO NPs and ultrastructural changes were assessed. A significant (p < 0.05) change in the CD4- and CD8-cells, levels of IL-6, IFN-γ and TNF-α and reactive oxygen species were observed in aged mice. In juvenile mice, increase in reactive oxygen species and IL-6 and TNF-α levels was observed with no significant changes in adult mice. A significant (p < 0.05) increase in the expression levels of mitogen activated protein kinase (MAPK) cascade proteins such as phospho-ERK1/2, phospho-JNK and phospho-p38 were also induced in aged mice. Collectively, our results indicate that the aged mice are more susceptible to ZnO NP induced immunotoxicity.

Evaluation of the effect of time on the distribution of zinc oxide nanoparticles in tissues of rats and mice: a systematic review.

To evaluate the time effect on the distribution of zinc oxide nanoparticles (ZnO NPs) in tissues from rats and mice, a search on the PubMed, Embase, SpringerLink, Scopus, Science Direct, Cochrane, CNKI, Wanfang, and vip databases up to September 2014 was performed, followed by screening, data extraction, and quality assessment. Thirteen studies were included. At 24 h, Zn content was mainly distributed in the liver, kidney, and lung. At ≥7 days, Zn content was mainly distributed in the liver, kidney, lung, and brain. ZnO NPs are readily deposited in tissues. Furthermore, as time increases, Zn content decreases in the liver and kidney, but increases in the brain.

The improvements in the size distribution of zinc oxide nanoparticles by the addition of a plant extract to the synthesis

AbstractRecently, the progress in using the plant extracts in the synthesis of nanoparticles (NPs) has occupied a lot of attention. In this study, zinc oxide nanoparticles (ZnO NPs) were synthesized in the presence and without the presence of a plant extract. The morphology and the size of ZnO NPs synthesized using these two methods were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, and Fourier transform infrared spectroscopy. XRD results were shown the wurtzite hexagonal type structure for the NPs and the average size of prepared NPs was found to be smaller, in the presence of plant extract. SEM images were confirmed the XRD results. Finally, the antibacterial activity of prepared NPs was evaluated against two bacteria of gram-positive staphylococcus aureus and gram-negative Escherichia coli.

Study of blueshift of optical band gap in zinc oxide (ZnO) nanoparticles prepared by low-temperature wet chemical method

We report synthesis of zinc oxide (ZnO) nanoparticles via wet chemical method using molar solutions of zinc nitrate hexahydrate [Zn(NO3)2·6H2O] and ammonium hydroxide (NH4OH) with polyvinylpyrollidone (PVP) as capping agent. The synthesized ZnO nanoparticles are characterized by X-ray diffraction (XRD) technique and electron microscopy (TEM and SEM with EDX) for compositional analysis and surface morphology. The average crystallite size calculated from XRD pattern has been found to be on the order of 8.5nm. In this work, the hyperbolic band model (HBM) and UV–vis absorption spectra have been utilized to calculate the band gap and nanoparticle size which was proposed by Meulenkamp. It was Meulenkamp who correlated the particle sizes with the wavelength at which the absorption becomes half of that at the shoulder (λ1/2). The optical band gap value of the prepared ZnO nanoparticle is found to be on the order of 3.63eV which indicates the presence of blueshift. In order to compare the size and distribution of ZnO nanoparticles, TEM has been utilized.

Synthesis and characterization of a narrow size distribution of zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnO-NPs) were synthesized via a solvothermal method in triethanolamine (TEA) media. TEA was utilized as a polymer agent to terminate the growth of ZnO-NPs. The ZnO-NPs were characterized by a number of techniques, including X-ray diffraction analysis, transition electron microscopy, and field emission electron microscopy. The ZnO-NPs prepared by the solvothermal process at 150°C for 18 hours exhibited a hexagonal (wurtzite) structure, with a crystalline size of 33 ± 2 nm, and particle size of 48 ± 7 nm. The results confirm that TEA is a suitable polymer agent to prepare homogenous ZnO-NPs.

Small angle neutron scattering and photoluminescence property of wet chemistry process synthesised ZnO nanoparticles

We report the synthesis of zinc oxide (ZnO) nanoparticles from aqueous solution at 25°C and subsequent heating of the solution at 115°C by the suitable selection of the solution chemistry and the control of the alkaline conditions. The structure of the synthesised ZnO particles was studied by X-ray diffraction (XRD), confirming the formation of Wurtzite structure. The optical property of synthesised ZnO nanoparticles is investigated through room temperature photoluminescence (PL) measurement. The PL of ZnO nanoparticles shows a strong UV emission band at approximately 385 nm, a blue–green band at approximately 473 nm and a very weak green band at approximately 554 nm, although polydispersity of the sample shows no presence on the PL spectrum. Small angle neutron scattering is used to determine the size and the size distribution of ZnO nanoparticles. The SANS data analysis and model fitting predict the size as about 18–20 nm, which is closely matched with XRD and transmission electron microscopy results with Gaussian distribution.