Zinc Oxide Content Research Articles

Mechanical and UV stability of HDPE composites reinforced with carbon black and zinc oxide for solar floater applications

Anti-UV (ultra-violet) hybrid polymer composites were developed for application in floating solar power plants. Virgin high-density polyethylene (HDPE) was mixed with carbon black (CB) in weight percentages of 1.5, 2, and 2.5% with 1, 2, and 3% zinc oxide (ZnO) to prevent the floater from degrading due to UV light. A twin-screw extruder was used to prepare the composite, and four batches were formed. The test sample was prepared by an injection molding machine. After 672, 1413, and 3212 hours of accelerated weathering, the mechanical tests were conducted. After 1413 hours of weathering, pure HDPE loses its tensile strength, impact resistance, and elongation at break. The optimum performance was observed in batch B2, which contains 2% CB and 2% ZnO, with respect to the mechanical properties after UV exposure. The scanning electron microscope (SEM),energy-dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) results also revealed that pure HDPE was more degraded compared to other composites. The strength of the polymer composite will decrease when ZnO and CB concentrations increase further. It was found that HDPE with 2% CB and 2% ZnO is an appropriate composite material for developing floaters used in floating solar power plants.

The effect of photoinitiator systems on resin-based composite containing ZnO-nanoparticles.

Zinc oxide (ZnO) powder possesses antibacterial activity and although white in color, it can severely reduce the depth of cure (DoC) of resin-based composite (RBC). This study investigated the effect of unary and binary photoinitiator systems on the DoC and degree of conversion (DC) of formulated RBC containing ZnO-nanoparticles. Fourteen RBCs (n = 3/group) were formulated consisting of 50 wt% mixture of monomers (Bis-GMA, TEGDMA, and UDMA) and 50 wt% fillers (inert barium glass powder and silica nanoparticles). ZnO-nanoparticles were added at 0 (control), 0.5, 1, 1.5 and 2 wt%. A unary initiator system consists of camphorquinone (CQ) 0.25, 0.5 and 1 wt% and ethyl 4-(dimethylamino)benzoate (EDMAB) 0.75 wt% or a binary initiator system consisting of diphenyliodonium hexafluorophosphate (DPI) 0.25, 0.5 and 1 wt%, CQ 0.25, 0.5 and 1 wt% and EDMAB 0.75 wt% were added to the monomer mixture. To measure the DoC, each specimen was prepared in a custom-made mold with a slot (16 x 8×2 mm) and a top cover plate, irradiated from one end (40 s), stored dry (37° C, 1 d) and measured at increasing depths using Vickers hardness (0.5 mm intervals). 1 mm thick specimens were prepared to measure DC continuously using FTIR, from zero up to 24 h post-irradiation. Increasing the concentrations of ZnO led to a significant reduction of DoC (p < 0.05). But most of the binary initiator groups showed significantly higher DoC (p < 0.05). Depth, at 80 % of max VHN, of unary initiator groups reduced from 6.8 mm (ZnO at 0 wt%) to 2.1 mm (ZnO at 2 wt%) and in binary initiator groups from 8.4 mm to 2.3 mm. Groups with lower photoinitiator concentrations (0.25 wt%) showed a significant increase in DoC compared with groups with higher concentrations (1 wt%) (p < 0.05). DC after 24 h was independent of either ZnO concentration or the photoinitiator system (p > 0.05). However, faster conversions were observed in binary initiator groups. The RPmax of binary groups ranged from 8.1 % to 10.1 %/s, and unary groups ranged from 5.2 % to 7.2 %/s. The addition of DPI resulted in an overall increased curing depth, which was enhanced when lower concentrations of photoinitiators were used. Also, DPI resulted in faster conversions. This is desirable in designing antibacterial RBC containing ZnO.

Synthesis and characterization of TiO2-ZnO composite thin films for biomedical applications.

Titania (TiO2) has superior biocompatibility, while zinc oxide (ZnO) is antibacterial. This investigation aimed to study the influence of TiO2-ZnO composite films on enhancing the biocompatibility of stainless steel (SS). Radio-frequency magnetron sputtering (RF-MS) technique is used to synthesize TiO2-ZnO composite thin films on 304-SS substrates from three sputtering targets with typical chemical compositions of 100% TiO2, 90%TiO2-10%ZnO, and 75%TiO2-25%ZnO, mixed by their respective weight percentages. The influence of surface chemistry, morphology, and wettability of TiO2-ZnO composite film on its osseointegration and antifouling characteristics was studied. The biocompatibility was assessed by protein adsorption kit, cytotoxicity assay, and cell adhesion of MG63 osteoblast cells, followed by S. aureus bacterial adhesion studies. All RF-MS films displayed hydrophobicity, minimal bacterial-cell adhesion, and higher cytocompatibility than the SS. RF-MS films deposited from the 75%TiO2-25%ZnO target exhibited the highest antifouling capability due to the least protein adsorption and the highest antibacterial ZnO concentration. However, increased ZnO concentration decreased MG63 cell viability. RF-MS films deposited from the 90%TiO2-10%ZnO target showed the highest mammalian cell viability of ≈88% and attachment. High plasma protein adsorption caused decreased mammalian cell viability and higher bacterial adhesion on 100% TiO2film and SS. Biocompatible and antifouling TiO2-ZnO composite thin films on SS substrates offer an alternative to conventional antibiotic coatings to combat antimicrobial resistance (AMR) and biofilm-related infections.

Chitosan-Based Zinc Oxide and Silver Nanoparticles Coating on Postharvest Quality of Papaya

The study aimed to investigate the effects of chitosan-based zinc oxide and silver nanoparticles coating on physicochemical properties of papaya and to optimize nanoparticles concentrations for extending its postharvest shelf life. The experiment was conducted in February, 2022 at the Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Kathmandu, Nepal, using a Completely Randomized Design (CRD) with nine treatments and three replications. The treatments consisted of different concentrations (50 ppm, 100 ppm, 150 ppm, and 200 ppm) of either Zinc oxide and silver nanoparticles, along with a control. Zinc oxide and silver nanoparticles were synthesized from banana peel extract and the average crystalline sizes were found to be 22.30nm and 4.46nm, respectively. Fruits were dipped in 1.5% (w/v) chitosan with 50–200 ppm of zinc oxide and silver nanoparticles and then stored at ambient temperature (14±1.6°C) and ~75% RH. The nanoparticles coatings slowed changes in total soluble solids (TSS) and total titratable acidity (TTA), delaying ripening. Treated fruits showed reduced physiological loss in weight and maintained firmness better than control, with firmness decreasing to 4.79 kg in untreated fruits compared to 7.35 kg in coated fruits on 18th day of storage. Coated fruits retained more ascorbic acid, and the storage life increased by 8 and 9 days with 150 and 200 ppm treatments, respectively. However, consumer preference declined for concentrations above 150 ppm. Thus, 100–150 ppm chitosan-based zinc oxide/silver nanoparticles are found to be effective for extending shelf-life and maintaining physiochemical characteristics of papaya. However, its residual and health-related dimensions need to be extensively studied before its commercial application. SAARC J. Agric., 22(2): 181-196 (2024)

Investigation of Chitosan-Based Hydrogels and Polycaprolactone-Based Electrospun Fibers as Wound Dressing Materials Based on Mechanical, Physical, and Chemical Characterization.

The aim of this project is to fabricate fiber mats and hydrogel materials that constitute the two main components of a wound dressing material. The contributions of boric acid (BA) and zinc oxide (ZnO) to the physical and mechanical properties of polycaprolactone (PCL) is investigated. These materials are chosen for their antimicrobial and antifungal effects. Additionally, since chitosan forms brittle hydrogels, it is reinforced with polyvinyl alcohol (PVA) to improve ductility and water uptake properties. For these purposes, PCL, BA, ZnO, PVA, and chitosan are used in different ratios to fabricate nanofiber mats and hydrogels. Mechanical, physical, and chemical characteristics are examined. The highest elastic modulus and tensile strength are obtained from samples with 6% BA and 10% ZnO concentrations. ZnO-decorated fibers exhibit a higher elastic modulus than those with BA, though BA-containing fibers exhibit greater elongation before breakage. All fibers exhibit hydrophobic properties, which help to prevent biofilm formation. In compression tests, CS12 demonstrates the highest strength. Increasing the PVA content enhances ductility, while a higher concentration of chitosan results in a denser structure. This outcome is confirmed by FTIR and swelling tests. These findings highlight the optimal combinations of nanofibrous mats and hydrogels, offering guidance for future wound dressing designs that balance mechanical strength, water absorption, and antimicrobial properties. By stacking these nanofibrous mats and hydrogels in different orders, it is expected to achieve a wound care material that is suitable for various applications. The authors encourage experimentation with different configurations of these nanofiber and hydrogel stackings to observe their mechanical behavior under real-life conditions in future studies.

Green‐Synthesized Zinc Oxide/Polyvinyl Alcohol /Cashew Gum/Polypyrrole Nanocomposites With Enhanced Mechanical, Thermal, and Electrical Properties for Nanoelectronics

ABSTRACTIn this study, ternary blend nanocomposites were synthesized through a green in situ polymerization process, utilizing zinc oxide (ZnO) nanofillers into a polyvinyl alcohol/cashew gum/polypyrrole (PVA/CG/PPy) matrix. The optical, morphological, structural, thermal, mechanical, and electrical properties of these nanocomposites were comprehensively analyzed using UV–visible spectroscopy, FTIR, XRD, FE‐SEM, TGA, and DSC. The findings revealed strong interactions between PVA, CG, PPy, and ZnO, with the uniform growth of spherical ZnO nanoparticles within the blend. Increasing ZnO content led to a reduction in optical bandgap energy, reaching 3.375 eV at its minimum. XRD revealed an intensified ZnO signal in the nanocomposites with higher ZnO concentrations. Thermal stability (TGA) and glass transition temperature (DSC) improved with increasing ZnO content, signifying strong interfacial adhesion between ZnO and the PVA/CG/PPy blend matrix. The nanocomposites also exhibited enhanced AC electrical conductivity and dielectric properties compared to the pristine blend. Notably, the dielectric constant, dielectric loss, and impedance decreased with rising temperature. Mechanical properties improved with a 39.6% increase in tensile strength at 3 wt% ZnO loading. ZnO was identified as an optimal nanofiller at 3 wt%, enhancing mechanical, thermal, and electrical properties, making these nanocomposites promising candidates for eco‐friendly, robust, and efficient nanoelectronic devices.

Effects of quantum dot zinc oxide, nano zinc oxide and zinc oxide on genes expression and aflatoxine production due to Aspergillus flavus ATCC50041

Aflatoxin, which is mainly produced by Aspergillus flavus and Aspergillus parasiticus, is a severe problem and threat in the fields of medicine and agriculture and is classified as the first class human carcinogen due to its carcinogenic, mutagenic, teratogenic, hepatotoxicity, and immune system defects. This toxin contaminates many agricultural products around the world. Considering the high toxicity of aflatoxin and the destructive effects of this metabolite, achieving low-risk and cost-effective methods to control toxin production is of great importance. In this study, the effects of different concentrations of quantum dot zinc oxide, nano zinc oxide, and zinc oxide on the expression of important key genes (aflR, aflP, aflM, aflD) in the gene cluster of aflatoxin production and also the amount of aflatoxin production (B1, B2) in Aspergillus flavus was studied. The fungus was cultured in different concentrations of quantum dot zinc oxide, nano zinc oxide, and zinc oxide (2000, 4000, 6000 ppm) for 3 days at 30 ◦C. The results showed that quantum dot zinc oxide significantly reduced toxin production and gene expression compared to other groups, in which the concentration of aflatoxin was decreased by increasing quantum dot zinc oxide. Regarding the obtained results, nano zinc oxide was effective just at 6000 ppm, and zinc oxide is suggested because nano zinc oxide and zinc oxide cannot completely dissolve in water. Hence, nano zinc oxide and zinc oxide showed weak activity in reducing aflatoxin concentration. All three agents under study significantly caused low gene expression, but quantum-dot zinc oxide showed more activity than the others. The formulation of highly active quantum dot zinc oxide to reduce aflatoxin may be a potential feed additive for the future management of mycotoxins.

REVIEW THE INFLUENCE OF ALUMINUM-ZNO FILMS ON MULTI-CHIP REMOTE-PHOSPHOR WHITE LEDS’ PROPERTIES

Zinc oxide (ZnO) exhibits stable emission across blue, green, orange, and red wavelength regions, depending upon excitation energy and preparation conditions. It is possible to tune the ZnO luminescent bandgap by introducing metal dopants to generate extrinsic defects in its matrix. Leveraging this stable and tunable photo-luminescent characteristic, ZnO emerges as a promising candidate for luminescent materials, especially applicable in the realm of luminescent converted LEDs. Specifically, aluminum-doped ZnO (Al-doped ZnO) films exhibit commendable conductivity and transmittance, qualifying them as suitable candidates for transparent conducting oxide materials crucial in LEDs. This study presents a novel application of Al-doped ZnO films, synthesized through a cost-effective sol-gel method, as a converter layer in white LED technology. The research systematically explores the impact of varying Aldoped ZnO concentrations on the color properties and luminosity of the white LED, with the goal of identifying the optimal concentration to achieve enhanced LED lighting efficiency.

Structural, and Physical properties of Antimonite glass in the (80-x) Sb2O3-20PbO-xZnO ternary system

The study of vitreous systems based on antimony oxide Sb2O3 has been investigated. The glass formation limits in the Sb2O3-PbO-ZnO ternary system are reported. The Tg is greater than 300°C, according to thermal measurements performed using differential scanning calorimetry. Tg increases with the zinc oxide content as a general rule. In the (80-x) Sb2O3-20PbO-xZnO system, the effect of ZnO substitution on optical and physical properties was investigated: As zinc oxide concentration rises, so do Vickers hardness and Young's modulus. E or density, an inverse relationship is observed. UV transmission has been stabilized at around 75%. The Urbach's band gap of the glass sample, 05% ZnO, is 2.69 eV, and it has a multiphonon relaxation with length =7.16m. FTIR and Raman spectra provide information on the structural of the glass, specifically the formation of pyramids based on triangular SbO3.

Synergetic Effect of Zinc Oxide and Zirconium Oxide Nanoparticles Concentrations on Antifungal and Physical Properties of Polymethyl Methacrylate Resin (PMMA)–An Invitro Analysis

Synergetic Effect of Zinc Oxide and Zirconium Oxide Nanoparticles Concentrations on Antifungal and Physical Properties of Polymethyl Methacrylate Resin (PMMA)–An Invitro Analysis

ZnOnp/CaCO3 Core–Shell Nanoparticle Coatings on Kraft Paper: A Comparative Study of Antimicrobial Efficacy, Tensile Strength, and Hydrophobicity

This study introduces a novel paper coating approach using modified zinc oxide (ZnO), providing a comparison with conventional materials used in the paper industry. The research focused on determining the concentration for effective microbial growth inhibition and evaluates the impact of different ZnO types on coated-paper properties, including antimicrobial activity, surface morphology, tensile strength, and water absorption. Specifically, ZnO microparticles (ZnOws), ZnO nanoparticles (ZnOnp), and modified ZnOnp (ZnOnp-CaCO3, with a core–shell structure composed of calcium carbonate [CaCO3] and nano-zinc oxide) were incorporated into coating formulations at varying concentrations (0 × MIC, 1 × MIC, 2 × MIC, and 3 × MIC, based on minimum inhibitory concentrations [MICs]). The results demonstrated that among all tested microorganisms, ZnOnp-CaCO3 showed the lowest MIC values. ZnOnp-CaCO3-coated paper exhibited superior antimicrobial activity against both Gram-positive and Gram-negative bacteria, as well as fungi, outperforming ZnOws and ZnOnp. At 1 × MIC, %inhibition for E. coli, S. aureus, and A. niger were 98.3%, 99.1%, and 90.8%, respectively. Additionally, ZnOnp-CaCO3 coatings caused minimal color change in the paper compared to the other ZnO variants. The coating did not negatively impact the mechanical properties of the paper across all ZnO types and concentrations. Water absorption tests showed increased hydrophobicity with higher ZnO content, with ZnOnp and ZnOnp-CaCO3 exhibiting greater reductions in water absorption than ZnOws. Overall, ZnOnp-CaCO3 showed strong potential as an antimicrobial agent for paper surfaces, making it ideal for packaging and hygiene products. By partially replacing ZnOnp with inexpensive CaCO3 core particles, ZnOnp-CaCO3 delivers enhanced performance, reduced costs, and greater sustainability for large-scale applications.

Thermodynamic modeling of converter sludge sintering

Currently, a promising area is the development of technologies for sintering or briquetting of converter sludge. Recycling of this sludge into production will allow solving a number of important tasks for modern metallurgy in the utilization of man-made waste, saving raw materials and reducing the cost of steel. The efficiency of utilizing useful components in the composition of briquettes is significantly higher than in any other state (in a fine or polydisperse fraction, in sorted form). In this paper, we consider the development and justification of an integrated approach to thermochemical sintering of converter sludge based on conditioning of iron-containing sludge by non-thermal adsorption dehydration and thermochemical sintering with simultaneous reduction of iron from oxides. Adsorption dehydration to a moisture content of 2 – 3 % is provided by a short-term contact of iron-containing slimes with a porous energy carrier, brown coal semi-coke, which is separated by pneumoseparation and sent for energy technological use, and the iron-containing product mixed with coals is subjected to thermo-oxidative coking. Coking is carried out in an annular furnace with a rotating hearth, where, when temperatures reach 1050 – 1100 °C, a large and durable lump material is formed with 55 – 60 % of the iron-containing product with almost complete reduction. Thermodynamic modeling of converter sludge sintering with coals was carried out. A tool for performing computational experiments using methods of thermodynamic modeling of the studied object was the Terra software package designed to calculate the thermodynamic properties and composition of the phases of equilibrium state of arbitrary systems with chemical and phase transformations. The results of thermodynamic modeling were fully confirmed by the experimental studies. The obtained material is an analog of ferrocox containing 35 – 39 % of iron and 45 – 49 % of carbon, while the zinc oxide content does not exceed 0.017 %.

Synthesis and Evaluation of a ZnO-Chitosan Adduct for Safe and Sustainable Enhanced Ultra-Violet (UV) Sunscreens Protection.

Chitosan (Ch), a natural polysaccharide, is known for its biocompatibility, biodegradability, and various beneficial properties, including antioxidant and antibacterial activities. The objective of this study is to investigate the functionalization of zinc oxide (ZnO) with chitosan to develop a novel ZnO@Ch adduct for use in cosmetic formulations, specifically as a sun protection agent. The functionalization was achieved through ionotropic gelation, which enhanced the stability and reduced the photocatalytic activity of ZnO, thereby improving its safety profile for skin applications. FTIR spectroscopy confirmed the successful functionalization, while TGA and DSC characterized the thermal properties and stability. The Zeta potential and particle size analyses demonstrated improved stability of ZnO@Ch across various pH levels compared to uncoated ZnO. The structure of the obtained adduct was also confirmed by SEM analysis. The ZnO@Ch adduct exhibited enhanced stability at neutral and slightly alkaline pH values, reduced photocatalytic activity compared to pure ZnO, and had lower cytotoxicity in 3T3 cells compared to pure ZnO, particularly at higher concentrations. The ZnO@Ch adduct provided a higher Sun Protection Factor (SPF) and UVA Protection Factor (UVA-PF) than pure ZnO, indicating enhanced UV protection. The adduct's ability to provide higher SPF at lower ZnO concentrations offers economic and environmental benefits, aligning with sustainable product design principles. Future studies will focus on optimizing the formulation and testing the efficacy and safety at higher concentrations to fully realize its potential as a natural, eco-friendly sunscreen ingredient.

Flexural strength and surface hardness of nanocomposite denture base resins

Higher bending forces during chewing and occlusal loading can lead to the deformation of denture bases. Roughness and microbial adhesion can be the result of improper care of the denture. Many attempts have been made to improve the properties of denture bases through the addition of different materials. The present study aimed to evaluate the surface hardness and flexural strength (FS) of newly formulated nanocomposite denture base resin made by adding zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles in heat polymerized polymethyl methacrylate resin in concentrations of 1% and 2%. Rectangular metal master dies of dimension 65mm×10mm×3.3mm for flexural strength and 30mm×10mm×3mm for surface hardness were made. These dies were duplicated in 120 acrylic resin samples. These samples were divided into five groups in which group I is control group samples in conventional resin and group II,III, IV &V contained 1% and 2% concentrations of ZnO & TiO2 nanoparticles in heat cure acrylic resin. The processing and finishing of the models were done. Flexural strength was measured using a universal testing machine and surface hardness using a Rockwell hardness testing machine. The minimum SH reported was 101.7 HRM while FS was 81.1MPa and maximum was 118.7 HRM and 131.8MPa respectively. The results showed that group IV containing 1% TiO2 nanoparticles showed the highest surface hardness values whereas the flexural strength was highest in group II containing 1% ZnO nanoparticles. The analysis of variance showed a p value of <0.001 which was statistically highly significant. Nanocomposite denture base resins modified with ZnO & TiO2 nanoparticles have more flexural strength and surface hardness than conventional denture base resin. The hardness of a denture base material can be increased by adding these nanoparticles for long term use in oral cavity and in cases prone to denture fracture.

Improving the distribution system capability by incorporating ZnO nanoparticles into high-density polyethylene cable materials

This paper introduces a novel insulated cable designed to enhance the distribution system’s capabilities. Accordingly, high-density polyethylene loaded with varying concentrations of zinc oxide (ZnO) nanoparticles (NPs) ranging from 0.0 to 5 wt% was prepared using the melt-blending technique. Zinc oxide (NPs) is synthesized by using sol–gel technique and their microstructure was examined by X-ray diffraction. The new insulated cable, HDPE nanocomposite loaded with 1 wt% of ZnO, demonstrates a 43% reduction in the relative dielectric constant and a 16.5% improvement in breakdown strength compared to pure HDPE. The observed changes in both the dielectric constant and breakdown strength offer several advantages in electrical applications. These benefits include a decrease in feeder current at the same loading level, mitigation of inrush transients during load switching, and a reduction in earth fault current values, particularly in unearthed distribution networks with ungrounded cables. A comparative study is conducted between the conventional insulating cable based on the original material (HDPE) and the new insulated cable incorporating ZnO nanomaterial at a ratio of 1.0 wt% of the total cable mass per unit length. This comparison utilizes data from two actual medium-voltage distribution feeders. Both actual feeders are simulated using the EMTP/ATP package. The obtained results prove the efficacy of the developed material cable (polymer doped with ZnO NPs) compared to the base material. The peak and duration of inrush current can be cut to 77.3% and 67% of their original values, respectively. The earth fault current can be reduced to 56.5% in ungrounded networks, while substation current under the normal operation can be cut to 84.3% with the same load currents.

Study on enhancing mechanical and thermal properties of carbon fiber reinforced epoxy composite through zinc oxide nanofiller

This study investigates the enhancement of mechanical and thermal properties of carbon fiber reinforced epoxy composites by incorporating zinc oxide (ZnO) nanofillers. The composites were developed by adding 3–15 g of ZnO nanoparticles into the epoxy matrix and were evaluated through experimental testing. The results showed significant improvements in mechanical performance, with the maximum tensile strength of 112.49 MPa and flexural strength of 114.82 MPa at the 15 g ZnO concentration. SEM analysis revealed a reduction in void content and improved fiber-matrix adhesion, enhancing load transfer. Thermal conductivity is 13.47 W/mK, while the coefficient of linear thermal expansion is 9.29 × 10−5/°C, indicating superior thermal stability. TGA analysis demonstrated a shift in decomposition temperature from 310 to 375 °C, confirming enhanced thermal stability. These results highlight the positive influence of ZnO nanofillers on both the mechanical and thermal properties of carbon fiber reinforced epoxy composites, making them more suitable for advanced structural applications.

Antimicrobial Effect of Zinc Oxide Nanoparticle Coating on Titanium 6 Aluminum 4 Vanadium (Ti-6Al-4V)-Fixed Orthodontic Retainer Substrate

Abstract Objectives Due to its excellent biocompatibility, superior mechanical qualities, and exceptional corrosion resistance, titanium 6 aluminum 4 vanadium (Ti-6Al-4V) alloy is frequently used for medical and orthodontic purposes as a fixed retainer after active orthodontic treatment. Titanium lacks the antibacterial characteristics and is bioinert, this may influence the usage of such materials in the field of biomedical applications. Bacterial adhesion to the orthodontic retainer surface is a common first step in infection; this is followed by bacterial colonization ending with the formation of a biofilm. Once biofilm forms, it is highly resistant to medicines and the host immune system's defense mechanism, making it difficult to remove the biofilm from orthodontic retainer. This study aimed to test the antimicrobial effect of a zinc oxide (ZnO) nanoparticle coating on Ti-6Al-4V orthodontic retainers. Materials and Methods ZnO nanoparticles, with a particle size of 10 to 30 nm, were used to coat the alloy using the electrophoretic deposition method. Various parameters and surface characterization tests were employed to obtain an optimized sample. This sample was subjected to the microbial adherence optical density test to examine the adherence of Streptococcus mutans, Lactobacillus acidophilus bacteria, and Candida albicans. Results The optimized sample had a 5-mg/L ZnO concentration, applied voltage of 50 V, and a 1-cm distance between electrodes. The ZnO coating significantly reduced microbial adherence compared to uncoated samples, effectively inhibiting bacterial development. Conclusion Electrophoretic deposition is an efficient and cost-effective technique for coating orthodontic titanium retainer substrates. Coating Ti-6Al-4V with ZnO nanoparticles increased the antimicrobial effectiveness of the material and as the concentration of the nanoparticles rises, the antimicrobial effect increases too.

Cellulose nanofibers-based UV resistant and hydrophobic wood coatings

Cellulose nanofibers-based UV resistant and hydrophobic wood coatings

MiRNA-driven sensitization of breast cancer cells to Doxorubicin treatment following exposure to low dose of Zinc Oxide nanoparticles

The impact of Engineered nanomaterials (ENMs) (i.e., Zinc Oxide nanoparticles (ZnO NPs)) on human health has been investigated at high and unrealistic exposure levels, overlooking the potential indirect harm of subtoxic and long exposures. Therefore, this study aimed to investigate the impacts of subtoxic concentrations of zinc oxide (ZnO NPs) on breast cancer cells' response to Doxorubicin. Zinc oxide nanoparticles caused a concentration-dependent reduction of cell viability in multiple breast cancer cell lines. A subtoxic concentration of 1.56µg/mL (i.e., no observed adverse effect level) was used in subsequent mechanistic studies. Molecularly, miRNA profiling revealed significant downregulation of 13 oncogenic miRNAs (OncomiRs) in cells exposed to the sub-toxic dose of ZnO NPs followed by doxorubicin treatment. Our comprehensive bioinformatic analysis has identified 617 target genes enriched in ten pathways, mainly regulating gene expression and transcription, cell cycle, and apoptotic cell death. Several tumor suppressor genes emerged as validated direct targets of the 13 OncomiRs, including TFDP2, YWHAG, SMAD2, SMAD4, CDKN1A, CDKN1B, BCL2L11, and TGIF2. This study insinuates the importance of miRNAs in regulating the responsiveness of cancer cells to chemotherapy. Our findings further indicate that being exposed to environmental ENMs, even at levels below toxicity, might still modulate cancer cells' response to chemotherapy, which highlights the need to reestablish endpoints of ENM exposure and toxicity in cancer patients receiving chemotherapeutics.

3D chitosan scaffolds loaded with ZnO nanoparticles for bone tissue engineering

Bone defect has always been a difficult problem in clinical work. According to the current research results, tissue engineered scaffolds with a single function, structure, and composition are not sufficient to repair complex bone defects. In this work, a three-dimensional (3D) chitosan degradable composite scaffold loaded with zinc oxide (ZnO) was constructed, and the effect of ZnO content on scaffold performance and osteogenesis was explored. The 3D composite scaffold was prepared by freeze-drying technology. The microstructure, porosity, degradation performance, release performance, swelling performance, cytotoxicity, cell adhesion and osteogenic ability of ZnO nanoparticles and chitosan (ZnONPs/CS) composite scaffolds were measured. The results show that an appropriate amount of ZnO may be helpful to regulate the stability and degradation characteristics of the scaffold to a certain extent. Moreover, the composite scaffold could release ZnO into the simulated body fluid environment. The appropriate amount of ZnO helps to promote the proliferation, adhesion, and osteogenic differentiation of MC3T3-E1 cells. At a ZnO content of 3 wt%, both in vitro and vivo results showed relatively optimal biocompatibility and bioactivity of the scaffolds. This work could at least provide some positive insights for the selection of ZnO dosage, construction of chitosan-based 3D scaffolds, tissue engineering applications, and clinical treatment.