nano-ZnO Particles Research Articles

Development of carboxymethyl cellulose/starch films enriched with ZnO-NPs and anthocyanins for antimicrobial and pH-indicating food packaging

Active packaging, which can monitor food freshness and extend the shelf life, has gained significant attention in recent years. This study aims to develop a novel carboxymethyl cellulose (CMC)/starch/anthocyanins/ZnO active films with enhanced properties and specific functionalities. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that the addition of anthocyanins and nano-ZnO particles (ZnO-NPs) led to heterogeneous microstructures and a slight decrease in the crystallinity. Fourier transform infrared spectroscopy (FTIR) indicated that there were no chemical interactions among film components. Active films containing ZnO-NPs exhibited improved ductility, as well as enhanced light barrier and water resistance properties. Notably, a shift from hydrophilic to hydrophobic behavior of the films was observed with high ZnO-NP content, as evidenced by a significant increase in the water contact angle (from 63.44° to 114.22°). Furthermore, the presence of only 1 % ZnO-NPs resulted in efficient inhibition of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) growth. Moreover, active films containing both anthocyanins and ZnO-NPs were highly sensitive to pH changes in buffer solutions (pH 2–11). Based on the results, a recommended film formulation for future active packaging applications is a 80:20 CMC/starch blend with 3 % ZnO-NPs and 0.1 g anthocyanins.

Difference in the toxic effects of micro and nano ZnO particles on L. minor - an integrative approach.

The toxicity of nano-sized ZnO particles (nZnO) was evaluated and compared to that of their micro-sized counterparts (mZnO) using an integrative approach to investigate the mechanism of toxicity, utilizing duckweed (Lemna minor) as plant model. Following 7days of exposure to nZnO or mZnO (2.5, 5, 25, and 50mg L-1) growth rate, photosynthesis, oxidative stress, and genotoxicity parameters have been determined in duckweed. Phytotoxicity of both ZnO forms at relatively low concentrations was due to the release of free Zn ions into the nutrient media. However, the accumulation of Zn in plants treated with nZnO was significantly higher than in those treated with mZnO. Both mZnO and nZnO significantly reduced growth rate and impaired the functionality of the photosynthetic apparatus as evidenced by structural changes of chloroplasts, a decline in the efficiency of photosystem II, and chlorophyll a content. Additionally, exposure to mZnO and nZnO resulted in the accumulation of reactive oxygen species (ROS), increased lipid peroxidation, the formation of carbonylated proteins, DNA damage, and alterations in antioxidant defense mechanisms. Overall, nZnO caused significantly stronger toxic effects than mZnO. The mechanism of nZnO toxicity to L. minor, as determined by multivariate statistical analysis, involved the disruption of primary photosynthetic reactions due to a redox imbalance in the cell caused by the enhanced absorption of Zn into plant tissues.

Nano-ZnO modified hydroxyapatite whiskers with enhanced osteoinductivity for bone defect repair

Abstract Hydroxyapatite (HA) whisker (HAw) represents a distinct form of HA characterized by its high aspect ratio, offering significant potential for enhancing the mechanical properties of bone tissue engineering scaffolds. However, the limited osteoinductivity of HAw hampers its widespread application. In this investigation, we observed HAw punctured osteoblast membranes and infiltrated the cell body, resulting in mechanical damage to cells that adversely impacted osteoblast proliferation and differentiation. To address this challenge, we developed nano-zinc oxide particle-modified HAw (nano-ZnO/HAw). Acting as a reinforcing and toughening agent, nano-ZnO/HAw augmented the compressive strength and ductility of the matrix materials. At the same time, the surface modification with nano-ZnO particles improved osteoblast differentiation by reducing the mechanical damage from HAw to cells and releasing zinc ion, the two aspects collectively promoted the osteoinductivity of HAw. Encouragingly, the osteoinductive potential of 5%nano-ZnO/HAw and 10%nano-ZnO/HAw was validated in relevant rat models, demonstrating the efficacy of this approach in promoting new bone formation in vivo. Our findings underscore the role of nano-ZnO particle surface modification in enhancing the osteoinductivity of HAw from a physical standpoint, offering valuable insights into the development of bone substitutes with favorable osteoinductive properties while simultaneously bolstering matrix material strength and toughness.

A novel anti-corrosion and antibacterial integrated MAO/PCNZ composite coating on AZ31B Mg alloy

Magnesium and its alloys possess elastic modulus close to natural bone and degradable effects, making them widely applied in bone implantation. However, their rapid corrosion in a simulated body fluid restricts further application. This work firstly employs micro arc oxidation (MAO) technique to in situ grow a corrosion-resistant ceramic layer on the surface of AZ31B Mg alloy. Subsequently, nano ZnO particles are modified using a silane coupling agent and then incorporated into a poly(ε-caprolactone) coating with chitosan through a simple blending and micellar method to obtain the PCNZ composite coating. The chemical composition and micro structure are characterized by FTIR, XRD, SEM and AFM. Electrochemical tests and antibacterial experiments indicate that PCNZ composite coating exhibits excellent long-term corrosion resistance and certain antibacterial ability, demonstrating potential application in the field of bone implantation.

Functionalized ZnO-Based Nanocomposites for Diverse Biological Applications: Current Trends and Future Perspectives.

The wide array of structures and characteristics found in ZnO-based nanostructures offers them a versatile range of uses. Over the past decade, significant attention has been drawn to the possible applications of these materials in the biomedical field, owing to their distinctive electronic, optical, catalytic, and antimicrobial attributes, alongside their exceptional biocompatibility and surface chemistry. With environmental degradation and an aging population contributing to escalating healthcare needs and costs, particularly in developing nations, there's a growing demand for more effective and affordable biomedical devices with innovative functionalities. This review delves into particular essential facets of different synthetic approaches (chemical and green) that contribute to the production of effective multifunctional nano-ZnO particles for biomedical applications. Outlining the conjugation of ZnO nanoparticles highlights the enhancement of biomedical capacity while lowering toxicity. Additionally, recent progress in the study of ZnO-based nano-biomaterials tailored for biomedical purposes is explored, including biosensing, bioimaging, tissue regeneration, drug delivery, as well as vaccines and immunotherapy. The final section focuses on nano-ZnO particles' toxicity mechanism with special emphasis to their neurotoxic potential, as well as the primary toxicity pathways, providing an overall review of the up-to-date development and future perspectives of nano-ZnO particles in the biomedicine field.

Durability Enhancement of Concrete with Recycled Concrete Aggregate: The Role of Nano-ZnO

The replacement of virgin aggregate with recycled concrete aggregate (RCA) in concrete mixtures offers an eco-strategy to mitigate the environmental limitations linked with traditional recycling techniques of RCA. However, the inferior properties of RCA, in contrast to virgin aggregate, present an obstacle to efficiently proceeding with this approach. Therefore, the aim of this study is to enhance the characteristics of concrete that contains RCA using nano-ZnO particles. Virgin aggregate was replaced with RCA in 30 wt.% and 50 wt.% ratios, followed by the addition of 0.5 wt.% nano-ZnO. The performance of concrete mixtures was evaluated in terms of their physical, mechanical, and durability properties. The addition of nano-ZnO particles to concrete with RCA resulted in refining its pore structure and reducing its water absorption, where the impermeability of concrete with 30 wt.% and 50 wt.% treated RCA decreased by 14.5% and 18%, respectively. Moreover, nano-ZnO treatment increased the compressive strength of mixtures with 30 wt.% and 50 wt.% RCA by 2.8% and 4%, respectively. All mixtures underwent a reduction in their 28-day compressive strength after exposure to a 5% sulphuric acid solution, where concrete with 30 wt.% and 50 wt.% RCA showed 20.2% and 22.8% strength loss, respectively. However, there was a 17.6% and 19.6% drop in the compressive strength of concrete with 30 wt.% and 50 wt.% RCA and treated with nano-ZnO.

Enhancing Cotton Fabric Softness and Wrinkle Resistance through Optimized Formulation of Nano ZnO and Benzalkonium Chloride-Enriched RinseCycle Softener

This work attempts optimization of a multifunctional single rinse softener formulation for cotton fabric for domestic usage, catering to the growing customer demand for softeners with enhanced performance. Present section is part-I of the entire study. The primary objective is to determine the effects of optimized and developed formulation on softness and wrinkle resistance properties. We synthesized polyvinylpyrrolidone (PVP) stabilized nano-ZnO particles using the sol-gel method and characterized them using UV-VIS spectrophotometry, particle size analyser and X-ray diffraction. Atomic absorption spectrometry (AAS), and Fourier transform infrared spectroscopy (FTIR) techniques were utilized for fabric sample analysis. Objective measurements using the Kawabata evaluation system, subjective softness assessments and crease recovery angle were recorded. The results demonstrated a significant enhancement in fabric softness, crease recovery and low stress mechanical properties through the application of this single rinse softener formulation. Any improving or diminishing effects on softness and crease recovery angle due to the presence of nano-ZnO (nano zinc oxide) and BAC (Bezalkonium chloride) were insightful.

Superhydrophobic epoxy resin coating with composite nanostructures for metal protection

Superhydrophobic coatings have high application value and wide range of practicality. However, in daily life, problems such as the stability of superhydrophobic coatings are unavoidable, which greatly hinders further developments in the application process. Through this research, we designed a highly stable superhydrophobic coating with a composite structure. That is, by using simple hydrothermal treatment and spraying technology, a superhydrophobic coating with rough structure was obtained by adding 1 H, 1 H, 2 H, 2 H-Perfluorooctyltrichlorosilane modified nano-SiO2 based on epoxy resin solution. Then, by adding stearic acid modified nano-ZnO (S-ZnO) particles, the structure and chemical bonding of the coating were enriched, and a stable superhydrophobic coating with composite nanostructures was prepared. The coating prepared under optimal conditions exhibited superb superhydrophobicity, the obtained water contact angle is 167.2° and the sliding angle is 2.1°. Meanwhile, the coating maintained marvellous superhydrophobicity under external mechanical damage (adhesive tape adhesion and sandpaper abrasion). In addition, the composite coating also exhibited good self-cleaning ability in dealing with solid pollutants and impurity liquids. Therefore, this composite nanostructured epoxy resin superhydrophobic coating can be used to effectively prevent matal corosion, and has the potential for mass production and daily uses.

Enhanced surface-insulating performance of EP composites by doping plasma-fluorinated ZnO nanofiller

The surface flashover of epoxy resin (EP) composites is a pivotal problem in the field of high-voltage insulation. The regulation of the interface between the filler and matrix is an effective means to suppress flashover. In this work, nano ZnO was fluorinated and grafted using low-temperature plasma technology, and the fluorinated filler was doped into EP to study the DC surface flashover performance of the composite. The results show that plasma fluorination can effectively inhibit the agglomeration by grafting –CF x groups onto the surface of nano-ZnO particles. The fluorine-containing groups at the interface provide higher charge binding traps and enhance the insulation strength at the interface. At the same time, the interface bond cooperation caused by plasma treatment also promoted the accelerating effect of nano ZnO on charge dissipation. The two effects synergistically improve the surface flashover performance of epoxy composites. When the concentration of fluorinated ZnO filler is 20%, the flashover voltage has the highest increase, which is 31.52% higher than that of pure EP. In addition, fluorinated ZnO can effectively reduce the dielectric constant and dielectric loss of epoxy composites. The interface interaction mechanism was further analyzed using molecular dynamics simulation and density functional theory simulation.

Supercritical hydrothermal synthesis of nano-ZnO: Effects of key parameters and reaction mechanism

In this paper, ZnO particles with the particle size as low as 23 nm were successfully prepared by supercritical hydrothermal synthesis technique. The particle size of nano-ZnO decreased with the increase of temperature and pressure. Nano-ZnO particles in ZnSO4 system were spherical with smaller particle size. The discrepancy in nano-ZnO produced by different precursor of Zn(NO3)2, Zn(CH3COO)2 or ZnSO4 is attributed to the anion effects and supersaturation. The particles in the KOH system (29 nm) were smaller than those in the NaOH system (44 nm). For precursor concentration, intermediate Zn(OH)2 was generated at lower concentration, while Zn4SO4(OH)6·4H2O was produced at higher concentration. For alkali concentration, as the gradual increase of KOH concentration, Zn(OH)2 began to decrease and gradually transformed into Zn(OH)3– and [Zn(OH)4]2−. When the KOH concentration reached a certain value, [Zn(OH)4]2− occupied the dominance in the mixed solution.

Analysis of Nano-ZnO-Modified Asphalt Compatibility Based on Molecular Dynamics.

Nano-ZnO has a large specific surface area, small particle size, and strong polarity and can be used as an additive to modify the base asphalt. In this paper, the compatibility mechanism between nano-ZnO modifier and asphalt is analyzed. Solubility parameters, interaction energNano-ZnO and mean square displacement of nano-ZnO in matrix asphalt were calculated at different temperatures to study the compatibility of the nano-ZnO modifier and the matrix asphalt. The radial distribution functions and radii of gyration of the asphalt's four components under the action of the nano-ZnO additive were calculated to investigate the effect of nano-ZnO on the molecular structure of the asphalt. The results show that the best compatibility between nano-ZnO and matrix asphalt is observed at 150 °C, especially when the nano-ZnO particle size was 6 Å. The particle sizes of nano-ZnO have little effect on the temperature at which the nano-ZnO-modified asphalt achieved its highest structural stability. Around 150 °C, the nano-ZnO-modified asphalt system with different particle sizes exhibit the highest stability and best compatibility. The addition of nano-ZnO improves the compactness of the asphalt structure and makes the asphalt more stable.

Study on the Properties and Morphology of Nano-ZnO Modified Asphalt Based on Molecular Dynamics and Experiments

Plenty of research has verified that nano-ZnO particles could improve the properties of asphalt, but studies on nano-ZnO-modified asphalt haven’t been conducted at the molecular level. Therefore, to investigate the effect of ZnO particles on the properties, structure and morphology of asphalt, the molecular dynamics (MD) methods were carried out. In this study, the models of asphalt, ZnO cluster and ZnO/asphalt blending systems with different particle sizes were built using Materials Studio software. Then, the interaction energies of ZnO/asphalt blending systems under different temperatures were calculated, and the effect of ZnO particles on the modulus and glass transition temperature of matrix asphalt was simulated. The results indicated that the bulk modulus of asphalt increased by ZnO with particle size at 4 Å, 6 Å, 8 Å and 10 Å increased by 15.09%, 12.46%, 10.06% and 8.51%, respectively, which can illustrate that the shear resistance ability and low-temperature properties of asphalt were enhanced. Compared with matrix asphalt, the glass transition temperature of the ZnO/asphalt system decreased by less than 0.1 K, indicating that ZnO’s effect on the low temperature of asphalt was not apparent. With the increase of ZnO particle size, the diffusion coefficient decreased sharply. Compared to matrix asphalt, when the particle size increased to 8 Å and 10 Å, the diffusion coefficient decreased by 13% and 22%, respectively. So, in practice projects, to achieve better dispersion of particle materials in base bitumen, a smaller particle size would be recommended. The results of the radial distribution function (RDF) and AFM simulation indicated that ZnO particles changed the micro-structure of asphalt and increased the roughness of the asphalt surface. As a result, ZnO particles bring matrix asphalt better physical properties.

Cu and Ni dual-doped ZnO nanostructures templated by cellulose nanofibrils for the boosted visible-light photocatalytic degradation of wastewater pollutants

Cu and Ni dual-doped nano-ZnO particles immobilized on cellulose nanofibrils were developed for boosting the photocatalytic performance towards the degradation of various wastewater pollutants under blue light irradiation.

Improvement of anti-corrosion performance (surface and near the cut edge) and mechanical properties of epoxy coatings modified with nano, micro and hybrid ZnO particles

Composites were formed by incorporating nano, micro and hybrid-ZnO particles into the epoxy matrix at the same loading levels (3%) and applied at 90 μm thickness on the galvanized steel substrate using a film applicator in this study. The improvement in anti-corrosion performance and mechanical and physical properties of the composite coatings were evaluated using various tests and techniques such as salt-spray, electrochemical impedance spectroscopy, nanohardness, microscratch, cross-cut, bending, Fourier transform infrared spectroscopy, thermogravimetric and Scanning electron microscopy. The corrosion performance of the composite coatings near the cut edge is discussed in detail as well as on the surface of galvanized steel. The results show that the addition of all ZnO particles has a positive effect on the corrosion resistance and mechanical properties of the coatings. The addition of nano, micro and hybrid ZnO particles increased the hardness of the composites by 52, 37 and 56%, respectively, compared to the neat epoxy. Although the cathodic protection performance is weakened near the cut edge due to the loss of Zn after thermal cutting, high barrier protection was provided with composite coatings, especially micro ZnO/Epoxy composite coating.

Highly Thermal Conductive and Electrically Insulating Epoxy Composites Based on Zinc-Oxide-Coated Silver Nanowires.

Nano-ZnO particles were deposited on the surface of silver nanowires (AgNWs) by the precipitation method, and the obtained AgNW@ZnO filler with core-shell structure was added to epoxy resin to prepare AgNW@ZnO/EP thermally conductive composites. The ZnO coating on the surface of AgNWs effectively improves the thermal conductivity of the composites. When 8 wt% AgNW@ZnO filler was added to the epoxy resin, the thermal conductivity of the AgNW@ZnO/EP composite increased to 0.77 W/(m·K). The enhancement of the thermal conductivity is attributed to the fact that ZnO effectively improves the interface bonding between AgNWs and the epoxy matrix, thus strengthening the contact between AgNWs. In addition, the electrical insulation of the AgNW@ZnO/EP composites was improved upon the introduction of the ZnO coating over AgNWs. For the filler content of 8 wt%, the volume resistivity of the AgNW@ZnO/EP composites was found to be higher than 1013 Ω·cm. AgNW@ZnO/EP composites have also exhibited low dielectric constant and good thermal stability.

Green synthesis of ZnO nanoparticles with enhanced photocatalytic and antibacterial activity

The study describes a concise and eco-friendly approach for synthesising nano ZnO (nZnO) particles using raw Garcinia Cambogia fruit pulp extract. The remarkable crystallinity, purity, and hexagonal wurtzite structure of nZnO are established by X-ray diffraction (XRD) analysis. The formation of almost spherical nZnO with an average diameter of 32.8 nm is revealed by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The Fourier Transform Infrared (FTIR) spectrum of nZnO outlines the synthesis mechanism. The recombinations of free excitons and oxygen vacancies are responsible for the peaks in the photoluminescence (PL) spectra. UV-Visible Diffuse reflectance spectroscopy (UV-Vis DRS) revealed that the optical bandgap of nZnO is 3.24 eV. nZnO exhibited excellent photocatalytic activity against the degradation of cationic and anionic dyes. The effects of process parameters on the extent of dye removal, such as photocatalyst quantity, solution pH, and time of irradiation, were investigated. The photocatalytic degradations of dyes were modelled by pseudo-first order kinetics, having a strong correlation coefficient (R2>0.95). Statistical assessments of dye degradation using Analysis of Variance (ANOVA) and Least Significant Difference (LSD) were conducted. Antibacterial studies show that nZnO has a substantial bactericidal effect against pathogenic bacteria. Consequently, the green synthesised nZnO might be utilised to eliminate dyes and bacteria from industrial effluent water in an environmentally benign and cost-effective way.

The impact of nano zinc oxide particles on the histology of the male reproductive system of adult male rabbits

The goal of our research is to evaluate the histological impact of nano ZnO particles (NZnO) on the testis and epididymis of adult male rabbits treated with I.P of 600mg/kg body weight of nano ZnO particles twice a week for three weeks and to the protective effect of vitamin E versus the effect of nano zinc oxide particles. Twenty-four adult male rabbits were used in this research and divided into four groups. The first group was the control group injected with intraperitoneal distal water, and the second group was injected with 600mg/kg body weight of nano Zno particles I.P. twice a week for three weeks, the third group was injected with 600 mg/kg body weight of nano Zno particles I.P. and co-administrated with 100 mg/kg body weight of vitamin e orally, while the fourth group received 100mg/kg body weight of vitamin e orally. The histological results showed that the nano ZnO particles treatment causes noticeable changes in the testis and epididymis. These changes are characterized by thickening of tunica albuginea of testis, degenerative and necrotic changes of germ cells lining the seminiferous tubules, arrest of spermatogenesis, giant cell formation, degeneration, and necrosis of epithelial cells lining epididymis canals. The canals are free from sperms is observed. As for the group of animals treated with nano ZnO particles co-administrated with vitamin e showed improvement in the histological changes compared with the control and group treated with vitamin e only showed normal architecture of testis and epididymis. Moreover, there is a decrease in the level concentration of Testosterone of the animals treated with nano ZnO particles compared with other groups.

Study of the Electrical Conductivity Characteristics of Micro and Nano-ZnO/LDPE Composites.

Polyethylene, a thermoplastic resin made by ethylene polymerization, is widely used in electrical insulation. In this study, low-density polyethylene (LDPE) is used as a matrix with micro- and nano-ZnO particles as a filler to produce different proportions of micro- and nano-ZnO composites by melt blending. These samples are characterized by Polarized Light Microscopy (PLM) and FTIR tests, with their conductance measured under different field strengths. The current density vs. electric field strength (J-E) curve of micro- and nano-ZnO composites under different field strengths are measured and analyzed. The J-E curves of different composites at different temperatures are measured to explore conductance with temperature. The results of these tests showed that nano-ZnO composites successfully suppressed conductivity at elevated temperatures and electric field strengths, while micro-ZnO composites increased the conductivity relative to pure LDPE.

High-efficiency oil-water separation and passive radiant cooling performance of nano-ZnO- embedded dust-free paper

Developing a flexible nano-composite material which is not only impermeable to low-polar oil, but also has the ability of daytime radiation cooling, remains a huge challenge for both academia and industry. By modifying the fiber network of the dust-free paper using nano-ZnO particles (ZnO-DF), we strategically designed and demonstrated dual capabilities of superhydrophilicity/superoleophobicity and daytime radiant cooling for the flexible cellulose nano-composite simultaneously. A superior surface with superhydrophilic/superoleophobic (oil contact angle up to 159° and water contact angle down to 0°) was attained by regulation of surface energy components and roughness. Furthermore, the materials revealed outstanding corrosion and mechanical damage resistance, 152,788 L m−2 h−1 high permeation flux and >99.2% continuous and efficient oil-water separation performance. In addition, a cooling effect of about 5.6 °C of ZnO-DF paper could be achieved by cooperative function of both radiative cooling and sweat evaporation. It is expected that the ZnO-DF paper is promising for the thermal management of wearable products integrated with passive radiant cooling, phase change cooling (e.g., sweat evaporation) and large-scale industrial oil-water separation.

Investigation of morphology, crystal structure and property of ZnO/poly (methylstyrene-co-chloromethyl styrene) nanocomposite

A nanocomposite composed of ZnO and poly (methyl styrene-co-chloro methyl styrene) P (MSt-co-CMSt) by in situ polymerization method were prepared successfully. For this purpose, firstly, the zinc oxide surface was treated with 3-(trimethoxysilyl) propyl methacrylate (TMSPMA), a silane coupling agent, and following that this functionalization nano-ZnO particle was reacted with PMSt to prepare PMSt-grafted TMSPMA-ZnO. The resulting PMSt-grafted TMSPMA-ZnO was brominated with N-bromosuccinimide and coupled with 1-hydroxy-2, 2, 6, 6-tetramethyl-1-piperidinyloxy (TEMPO-OH) to produce an NMRP macroinitiator (PMSt-TEMPO/nano-ZnO). The well-controlled graft polymerization of 4-chloromethyl styrene (CMSt) with macroinitiators were carried out to produce nanoparticles based-ZnO (PMSt-co-PCMSt)/zinc oxide nanocomposite). Properties, crystal structure, and the morphology of (PMSt-co-PCMSt)/zinc oxide nanocomposite was studied using 1H-NMR, FT-IR, XRD, TGA, DSC, TEM, and UV-Vis spectroscopy. The results of FT-IR investigation and observations of TEM images represented clear and strong evidence for the preparation of PMSt and PMSt-co-PCMSt with spherical morphology of ZnO nanoparticles. The synthesized nanocomposites can be utilized a compound to attenuate the UV irradiation in the range of pointed wavelength.