Zinc Oxide Research Articles

Three different methods for ZnO-RGO nanocomposite synthesis and its adsorption capacity for methylene blue dye removal in a comparative study

Water is one of the vital needs of life. However, due to rapid industrialization, urbanization and lack of awareness, the world population now facing the threat of water shortage. To ensure that future living conditions are preserved, it is crucial to reduce water pollution and protect the ecosystem. Zinc oxide- reduced graphene oxide (ZnO-RGO) nanocomposite is used in this study as an adsorbent for the adsorption of methylene blue (MB) dye from an aqueous solution. An easy strategy was used for the synthesis of reduced graphene oxide nanoparticles (RGO), Zinc oxide nanoparticles (ZnO) and ZnO-RGO nanocomposite. The synthesis of reduced graphene oxide (RGO) was accomplished through the exothermic reaction of a modified Hummer's method. In a novel approach, zinc oxide nanoparticles (ZnO NPs) were synthesized using the green Leidenfrost technique. This study presents a comparative investigation of ZnO-RGO nanocomposite synthesis employing both green and chemical methods. Three distinct approaches were utilized to prepare the ZnO-RGO nanocomposite: (1) the innovative Leidenfrost green method for composite A1, (2) a chemical precipitation method for composite A2, and (3) a physical mixing sonication method for composite A3. This research marks the first application of the Leidenfrost technique in the synthesis of ZnO-RGO nanocomposites, contributing to the growing body of knowledge in this field. X-ray diffraction (XRD), Burnauer-Emmett-Teller (BET), Fourier transform infrared (FTIR), Zeta potential, transmittance electron microscope (TEM) and scanning electron microscope (SEM) analyses are conducted for synthesized sample characterization. Comparing the XRD patterns of the three synthesis methods, it is notable that the intensity peaks of composite A3 were the highest when ZnO was synthesized using a green method, indicating a higher degree of crystallinity. FTIR analysis approves that combining ZnO with RGO affects the functional groups of the three nanocomposite surfaces. The SEM analysis shows ZnO NPs and RGO sheets are incorporated together. In the case of A1 composite sharp angles make a flower shape was observed due to the unique synthesizing method. The surface area for A2 composite is the highest (7.29 m2/g) compared with A1 (2.91 m2/g) and A3(1.90 m2/g). A comparison study is made among the three nanocomposites for MB dye removal. The effect of adsorbent dose, pH, contact time and initial dye concentration on dye adsorption has been studied. The results show that A1 and A2 nanocomposites removed 85.5 and 87.5% of MB at the optimum adsorbent dose of 0.15 g/100 ml at pH8 and A3 removed 95% of MB at the optimum dose of 0.1 g/100 ml at pH 2. All three composites exhibited adherence to the Langmuir isotherm model, with correlation coefficients (R2) of 0.9858, 0.9904, and 0.9959 for A1, A2, and A3, respectively. Kinetic study results demonstrated that the pseudo-second-order model best described the adsorption process for all three composites, yielding R2 values of 0.9998, 0.9988, and 1.0000 for A1, A2, and A3, respectively. The A3 nanocomposite shows the highest adsorption capacity (104.5 mg/g) compared to the other composites (87.7 and 97.5 mg/g for A1 and A2, respectively). Desorption experiments revealed that the dye removal percentages varied with the ratio of the ethanol–water mixture used. Absolute ethanol achieved a 90% removal compared with 1:1 and 1:2 aqueous ethanol solutions (87.5% and 80%, respectively).

Time-domain analysis of mode competition in ZnO nanowire lasers in inhomogeneous environments

Zinc oxide (ZnO) nanowire lasers are increasingly integrated into complex optoelectronic devices as a source of coherent radiation. To enable the rational design of these devices, it is crucial to understand how both the nanowire resonator and its surrounding environment influence mode competition and the three-dimensional structure of lasing modes. Additionally, realistic models of the lasing process must account for transient gain dynamics. In order to investigate the impact of an inhomogeneous environment, composed of various materials and structures, on mode competition, we conducted Finite-Difference Time-Domain (FDTD) simulations of the dominant lasing modes in different ZnO nanowire laser configurations. Our model describes how key parameters such as nanowire diameter, length, and substrate choice affect the field distribution in the lasing regime. We show that metallic substrates support lasing in thin nanowires in two distinct coupling regimes. Furthermore, we show that metallic particles attached to the nanowire end facets as a result of established nanowire growth techniques significantly influence lasing threshold, field distribution and competition between counter-propagating modes. We show that attaching an aluminum particle at the end facet of a ZnO nanowire leads to a threshold reduction, a switching of the dominant lasing mode and a mono-directional power flow inside a large segment of the nanowire.

Acidic Engineering on Buried Interface toward Efficient Inorganic CsPbI3 Perovskite Light-Emitting Diodes.

Inorganic CsPbI3 perovskite has emerged as a promising emitter for deep-red light-emitting diodes (LEDs) due to its intrinsic thermal stability and suitable bandgap. However, uncontrollable CsPbI3 crystallization induced by an alkaline zinc oxide (ZnO) substrate in bulk film-based LEDs leads to insufficient external quantum efficiencies (EQEs) at high brightness, leaving obstacles in commercialization progress. Herein, we demonstrate an effective acidic engineering strategy with wide applicability to modify the surface property of ZnO and regulate CsPbI3 crystallization. Via systematically selecting 1,4-cyclohexanedicarboxylic acid with a mild acid dissociation constant to functionalize the buried interface, we mitigate the speed of the deprotonation reaction and achieve homogeneous CsPbI3 films with high phase purity and fewer defects. The resulting CsPbI3 perovskite LEDs (PeLEDs) exhibit a record EQE of 19.4% at a high luminance of 3400 cd m-2, representing the state-of-art bulk CsPbI3 PeLEDs. These findings provide valuable insights in the advancement of efficient CsPbI3 PeLEDs.

Foliar Application and Translocation of Radiolabeled Zinc Oxide Suspension vs. Zinc Sulfate Solution by Soybean Plants

The present study employed a 65Zn radioactive isotope as a tracer to investigate the foliar uptake and distribution patterns of ZnO concentrated suspension- and ZnSO4 solution-sprayed on soybean plant leaves. The radiolabeled foliar treatments were sprayed on the leaves at V4 and V8 phenological stages. The radioactivity of 65Zn in the leaves, roots, stems, and pods was determined using γ-ray spectrometry. After the first foliar spray, V4, the partition of radiolabeled Zn in plants treated with ZnO and ZnSO4 was 99.22% and 98.12% in treated leaves, 0.15% and 0.39% in stems, 0.16% and 0.29% in roots, and 0.47% and 1.19% in newly expanded non-treated leaves, respectively. After two sprayings, V4 and V8, the partition of radiolabeled Zn in plants treated with ZnO and ZnSO4 was 92.56% and 92.18% in treated leaves, 0.92% and 0.70% in stems, 0.52% and 0.39% in roots, 5.60% and 6.15% in newly expanded non-treated leaves, and 0.43% and 0.61% in grains, respectively. The total fraction translocated from the application tissue was 0.79% and 1.91% for ZnO and ZnSO4, respectively, after 12 days and 8.03% and 8.48% for ZnO and ZnSO4, respectively, after 72 days. An anatomical analysis revealed that plants cultivated in a nutrition solution with 10% ionic strength had 63% fewer stomata, and the xylem vessels were 63% smaller compared to plants grown in a solution with 100% Zn ionic. One can conclude that after a short period, 12 days, the absorption and translocation of ZnSO4 was higher and faster than ZnO, and after the long period, 72 days, their performance was similar.

Biosynthesis of Zinc Oxide Nanoparticles Using Dried Leaves of Camellia sinensis: Methods to Characterize and Assess Their Effects on Mesenchymal Stem Cell Viability.

Stem cell nanotechnology (SCN) is an important scientific field to guide stem cell-based research of nanoparticles. Currently, nanoparticles (NPs) have a rich spectrum regarding the sources from which they are obtained (metallic, polymeric, etc.), the methods of obtaining them (physical, chemical, biological), and their shape, size, electrical charge, etc. properties. It is also essential to expand green synthesis applications for the use of NPs in the field of biomedical sciences. For this purpose, there is a need to produce NPs using biological sources (plant, microorganism, algae, yeast etc.…), characterization and investigation of their effects on biological activities of stem cells. This process involves long and laborious procedures, and there may be differences in methods between individual laboratories.In this protocol, biofabrication and characterization of ZnO NPs using dried leaves of Camellia sinensis is described. This experimental setup includes conventional and novel methods that can be applied to biofabricate and characterize the NPs and to examine the viability, apoptotic, and necrotic effects on human adipose tissue-derived mesenchymal stem cells (ADMSCs) in vitro.

Comparative Histological Assessment of Zinc Oxide Nanoparticles and Low-Power Laser Treatment at 810nm Wavelength on the Recovery of Second-Degree Burn Wounds in Rat Models.

Background: The utilization of zinc oxide nanoparticles is thought to augment wound healing because of their antibacterial characteristics and capacity to stimulate cellular regeneration, especially in instances of minor burn injuries. On the other hand, it has been shown that tissue regeneration is aided by low-power laser therapy via photobiomodulation. Zinc oxide nanoparticles and low-power laser therapy are the two therapeutic modalities that will be compared in this study in order to assess how well they promote healing after burn injury and provide important new information on improved wound care techniques. Methods: For this investigation, thirty male Wistar rats weighing 230 ± 25 grams each were split into three groups. Every rat received general anesthesia before the experiment. A stainless-steel rod was put to the rats' skin after being heated for 20 min in a boiling water bath to cause superficial second-degree burns. The control group functioned as a reference point for comparison and did not receive any treatment intervention. Over the course of a week, zinc oxide nanoparticles were applied topically to the second group. For one week, the third group received daily therapy with a diode laser at a dosage of 10 J/cm.1 Histological and clinical exams were performed after the therapy period to evaluate the impact of the therapies. Results: The experimental groups that received low-power laser therapy (third group) and zinc oxide nanoparticles (second group) showed a substantial increase in wound contraction in relation to the control group, based on macroscopic observations. One rat from the second group showed notable indications of full wound healing on day 21. The treated rats showed the highest rate of lesion contraction, indicating that wound treatment happened at least 7 days faster in these rats than in the other groups. After 21 days, the third group's epidermis fully epithelized and formed a layer of keratinization. Furthermore, there was enhanced angiogenesis and significant fibroblast proliferation; large-scale fibrosis was also commonly seen. Conclusion: Zinc oxide nanoparticles promoted wound healing and accelerated connective tissue regeneration faster than other groups when applied to second-degree superficial burns. This research implies that the use of zinc oxide nanoparticles may be a therapeutic approach that shows promise for treating burn injuries and improving patient outcomes.

Review of: "Nanowires can be made from various conductive and semi-conductive materials such as copper, silver, gold, iron, silicon, zinc oxide and germanium."

Review of: "Nanowires can be made from various conductive and semi-conductive materials such as copper, silver, gold, iron, silicon, zinc oxide and germanium."

Influence of zinc oxide nanoparticles on the carbon accumulation on silver exposed to carbon dioxide hydrogenation reaction conditions.

The strong influence of surface adsorbates on the morphology of a catalyst is exemplified by studying a silver surface with and without deposited zinc oxide nanoparticles upon exposure to reaction gases used for carbon dioxide hydrogenation. Ambient pressure X-ray photoelectron spectroscopy and scanning tunneling microscopy measurements indicate accumulation of carbon deposits on the catalyst surface at 200 °C. While oxygen-free carbon species observed on pure silver show a strong interaction and decorate the atomic steps on the catalyst surface, this decoration is not observed for the oxygen-containing species observed on the silver surface with additional zinc oxide nanoparticles. Annealing the sample to temperatures above 350 °C removes the contaminants by hydrogenation to methane.

Oxygen-modulated photoresponse in nickel oxide thin films for wide band gap photodetector application

Metal oxides, due to their wide band gap, are well suited for use in photodetectors as the active light-absorbing layer. While there have been extensive studies on n-type oxides, such as tungsten oxide and zinc oxide, there is relatively little work on the use of p-type oxides, such as nickel oxide (NiO), for photodetectors. Using these p-type oxides along with n-type conducting oxides to form heterojunctions can improve the detection capabilities by efficient separation of charge carriers. In this work, the photoresponse of a p-type NiO thin film, grown by room temperature reactive magnetron sputtering from a pure nickel target onto a conducting n-type indium-doped tin oxide (ITO) substrate, is investigated. Different ratios of oxygen to argon (10/45, 15/45, and 20/45) during sputtering are investigated, and the effect of oxygen concentration on the optical properties of the NiO film is studied, which helps in modulating the photoresponse of the developed detector. The O2/Ar ratio, with a value of 15/45, is found to perform better among the three ratios. For the corresponding photodetector, the current under illumination, is found to be nearly three orders of magnitude higher than the dark current, even at a very low applied voltage of 0.1 V. The calculated responsivity (at 0.012 A/W) is found to be the best among all three values. The device also has an excellent transient current response with a rise time of 0.5 s and a decay time of 1.4 s, which is the fastest transient behavior among all three ratio-based devices. The work paves the way for using metal oxide-based heterojunctions as wide band gap photodetectors.

Therapeutic Advantages of Nanoparticle-Impregnated Lysozyme Conjugates toward Amyloid-β Fibrillation and Antimicrobial Activity.

The interaction of protein with nanoparticles (NPs) of varying shape and/or size boosts our understanding on their bioreactivity and establishes a comprehensive database for use in medicine, diagnosis, and therapeutic applications. The present study explores the interaction between lysozyme (LYZ) and different NPs like graphene oxide (GO) and zinc oxide (ZnO) having various shapes (spherical, 's', and rod-shaped, 'r') and sizes, focusing on their binding dynamics and subsequent effects on both the protein fibrillation and antimicrobial properties. Typically, GO is considered a promising medium due to its apparent inhibition and prolonged lag phase for LYZ fibrillation. However, the present results showed that spherical ZnO NPs (sZnO) offer superior efficacy in modulating fibrillation with an extended lag time of about 158.70 h, further emphasizing the importance of detailed investigation on the nanomaterial characteristics and fibril formation kinetics beyond initial observations. The experimental findings further confirmed a strong correlation between the binding affinity of NPs to the native protein and their effective inhibition of protein denaturation, ultimately preventing fibril formation. Interestingly, the lysozyme nanoconjugates showed intriguing bactericidal effects, as confirmed through the agar plate assay and SEM imaging, over the native protein. Overall, this study shows that appropriate bionanomaterials can exhibit multifunctional properties, which paves the way for a deeper investigation of NP characteristics, ultimately benefiting a wide array of intriguing research.

Crystal Structure Evolution of Piezoelectric Fe-Doped ZnO Film by Magnetron Co-Sputtering Technique

Zinc oxide (ZnO) exhibits piezoelectric properties due to its asymmetric structure, making it suitable for piezoelectric devices. This experiment deposited Fe-doped ZnO films on silicon substrates using a dual-target magnetron co-sputtering system. The films achieved a high c-axis orientation, and the piezoelectric coefficient of the film reached its optimal value of 44.35 pC/N when doped with 0.5 at% of Fe. This value is approximately three times that of undoped ZnO films with a piezoelectric coefficient of 13.04 pC/N. The study utilized a diffractometer, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy to evaluate the crystal structure evolution of the zinc oxide films and employed X-ray photoelectron spectroscopy to assess the valence state of the Fe ions.

Nano-Zinc Oxide Can Enhance the Tolerance of Apple Rootstock M9-T337 Seedlings to Saline Alkali Stress by Initiating a Variety of Physiological and Biochemical Pathways

Soil salinization severely restricts the growth and development of crops globally, especially in the northwest Loess Plateau, where apples constitute a pillar industry. Nanomaterials, leveraging their unique properties, can facilitate the transport of nutrients to crops, thereby enhancing plant growth and development under stress conditions. To investigate the effects of nano zinc oxide (ZnO NP) on the growth and physiological characteristics of apple self-rooted rootstock M9-T337 seedlings under saline alkali stress, one-year-old M9-T337 seedlings were used as experimental materials and ZnO NPs were used as donors for pot experiment. Six treatments were set up: CK (normal growth), SA (saline alkali stress,100 mmol/L NaCl + NaHCO3), T1 (saline alkali stress + 50 mg/L ZnO NPs), T2 (saline alkali stress + 100 mg/L ZnO NPs), T3 (saline alkali stress + 150 mg/L ZnO NPs) and T4 (saline alkali stress + 200 mg/L ZnO NPs). The results were found to show that saline alkali stress could significantly inhibit the growth and development of M9-T337 seedlings, reduce photosynthetic characteristics, and cause ion accumulation to trigger osmotic regulation system, endogenous hormone and antioxidant system imbalances. However, the biomass, plant height, stem diameter, total leaf area and leaf perimeter of M9-T337 seedlings were significantly increased after ZnO NP treatment. Specifically speaking, ZnO NPs can improve the photosynthetic capacity of M9-T337 by increasing the content of photosynthetic pigment, regulating photosynthetic intensity and chlorophyll fluorescence parameters. ZnO NPs can balance the osmotic adjustment system by increasing the contents of soluble protein (SP), soluble sugar (SS), proline (Pro) and starch, and can also enhance the activities of enzymatic (SOD, POD, and CAT) and non-enzymatic antioxidant enzymes (APX, AAO, GR, and MDHAR) to enhance the scavenging ability of reactive oxygen species (H2O2, O2•−), ultimately reducing oxidative damage; ZnO NPs promoted the growth of M9-T337 seedlings under saline alkali stress by synergistically responding to auxin (IAA), gibberellin (GA3), zeatin (ZT) and abscisic acid (ABA). Additionally, the Na+/K+ ratio was reduced by upregulating the expression of Na+ transporter genes (MdCAX5, MdCHX15, MdSOS1, and MdALT1) and downregulating the expression of K+ transporter genes (MdSKOR and MdNHX4). After comprehensive analysis of principal components and correlation, T3 (150 mg/L ZnO NPs) treatment possessed the best mitigation effect. In summary, 150 mg/L ZnO NPs(T3) can effectively maintain the hormone balance, osmotic balance and ion balance of plant cells by promoting the photosynthetic capacity of M9-T337 seedlings, and enhance the antioxidant defense mechanism, thereby improving the saline alkaline tolerance of M9-T337 seedlings.

Biosynthesis and activity of Zn-MnO nanocomposite in vitro with molecular docking studies against multidrug resistance bacteria and inflammatory activators

This study investigated the green synthesis of Zn-MnO nanocomposites via the fungus Penicillium rubens. Herein, the synthesized Zn-MnO nanocomposites were confirmed by UV-spectrophotometry with a top peak (370 nm). Transmission electron microscopy confirmed irregular particles with a spherical-like shape ranging from 25.13 to 36.21 nm. Numerous functional groups were detected on the surface of Zn-MnO nanocomposite via Fourier-transform infrared spectroscopy. X-Ray diffraction assay appeared that the synthesized Zn-MnO nanocomposites contained two different components, MnO (JCPDS 81-2261) and ZnO (JCPDS 36-1451), while energy dispersive X-ray spectra confirmed the occurrence of manganese, zinc, oxygen, and carbon in Zn-MnO nanocomposites. Zn-MnO nanocomposites demonstrated excellent suppress effect versus the growth of various bacteria namely Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), Salmonella typhi, and Klebsiella pneumoniae via agar well diffusion assays with inhibition areas of 36 ± 0.1, 25 ± 0.1, 27 ± 0.2, and 23 ± 0.2 mm, correspondingly. Alterations in the ultrastructure of the treated K. pneumoniae by Zn-MnO nanocomposite were recorded. Both the values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration of Zn-MnO nanocomposite extended from 15.62 to 125 µg/mL employing the examined bacteria. The antibiofilm activity of Zn-MnO nanocomposites was 82.07, 75.43, 43.65, and 41.35% at 25% MIC, and 96.54, 93.0, 94.53, and 91.11% at 75% MIC against S. aureus, MRSA, K. pneumoniae, and S. typhi, respectively. At 25 to 75% MIC, Zn-MnO nanocomposites exhibited antihemolytic activity with the maximum activity of 96.3% at 75% MIC in the presence of MRSA. Extensive molecular docking studies were performed to identify the optimal location for manganese oxide and zinc oxide nanoclusters binding to MRSA. MnO-NPs and ZnO-NPs demonstrated inhibitory activity against the crystal structure of putative minohydrolase (PDB ID: 4EWT), methicillin acyl-penicillin binding protein 2a structure (PDB ID: 1MWU) and K2U bound crystal structure of class II peptide deformylase from MRSA (PDB ID: 6JFQ). The minimum binding energy was utilized to estimate the receptor’s binding site with NPs, providing additional understanding of the ways of action. Anti-inflammatory activity of Zn-MnO nanocomposites via cyclooxygenase-1 and cyclooxygenase-2 enzymes inhibition was documented with IC50 doses of 20.81 ± 0.68 µg/mL and 35.87 ± 1.35 µg/mL, respectively. Based on these outcomes, it was concluded that Zn-MnO nanocomposites could be useful agents for the management of multidrug resistant bacterial pathogens and inflammation.

Annealing Temperature Effects of Seeded ZnO Thin Films on Efficiency of Photocatalytic and Photoelectrocatalytic Degradation of Tetracycline Hydrochloride in Water

In this study, seeded zinc oxide (Z-ZnO) thin films were fabricated by a two-step electrochemical deposition process. Different annealing temperatures (300, 400, 500, and 600 °C) were investigated to determine the most effective temperature for the photocatalytic activity. Comprehensive analyses were conducted using X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and UV–visible spectrophotometry. The XRD results confirmed the formation of a wurtzite hexagonal structure, with the highest crystallinity observed at 400 °C. The lowest band gap value, 3.29 eV, was also recorded for Z-ZnO thin film annealed at 400 °C. SEM images revealed that the thin film treated at 400 °C exhibited a well-defined and uniform structure, contributing to its enhanced properties. The photocatalytic efficiency of ZnO (without seeding layer) and Z-ZnO thin films annealed at 400 °C was evaluated through the degradation of tetracycline hydrochloride (TCH) to prove the effect of the presence of a primary seeding layer on ZnO 400 °C thin film efficiency. The degradation efficiency of ZnO thin film without seeding layer was 69.8%. By applying a seeding layer in Z-ZnO 400 °C thin film, the degradation efficiency has been increased to 75.8%. On the other hand, Z-ZnO 400 °C thin film achieved a high degradation efficiency of 82.6% over 300 min in the photoelectrocatalytic system. The obtained Z-ZnO thin films annealed at 400 °C are highly effective photocatalysts and photoelectrocatalysts, offering a significant potential for the degradation of pharmaceuticals and other pollutants in water.

Synergy of zinc oxide nanoparticles to losartan attenuates kidney injury induced by unilateral ureteral obstruction through modulation of the TNF-α/IL6 and BAX/BCL2 signaling pathways.

Although the relief of ureteral obstruction seems to be a radical treatment for obstructive uropathy (OU), progressive kidney damage is the result because of the associated increased apoptosis and fibrosis. Therefore, it is urgent to find a complementary renoprotective therapy against partially obstructed uropathy cascades. Thus, this study investigated the renoprotective effects of both losartan (LOS) and zinc oxide nanoparticles (ZnONPs) in partial unilateral ureteral obstruction (PUUO). In controlled (n = 16) and shamed (n = 16) study, 64 healthy male Sprague-Dawley rats, both PUUO and right nephrectomy (RNX) were induced. The rats were equally allocated into four groups according to treatment protocol: (1) PUUO group (no treatment), (2) ZnONPs group, (3) LOS group and (4) ZnONPs/LOS group. Antioxidant status and gene expression were assessed in renal tissues. Moreover, histologic and immunohistochemical examinations were performed. LOS and ZnONPs significantly mitigated the PUUO-induced renal injury, by significant (P < 0.0001) suppressing of oxidative stress (MDA and TOS), upregulating of antioxidant gene (SOD) and antiapoptotic gene (BCL2), and downregulating the expression of inflammatory cytokines (TNF-α, and IL6), apoptotic gene (Bax) and fibrotic marker (β-Catenin). The combination of both agents offered a more powerful renoprotective effect with additional significant upregulation of the antioxidant marker (TAC, P < 0.0001). Both losartan and ZnONPs and specially their combination have synergistic action in protecting the kidney against PUUO-induced chronic renal cascades through improvement the renal function tests, amelioration of oxidative stress, inhibition of induced apoptosis and fibrosis with marked renal regeneration which highlights the possible application of these drugs as a complementary therapies for different chronic renal degenerative diseases.

Green Synthesis of Silver-Doped ZnO Nanoparticles From Adiantum venustum D. Don (Pteridaceae): Antimicrobial and Antioxidant Evaluation.

One of the main difficulties in nanotechnology is the development of an environmentally friendly, successful method of producing nanoparticles from biological sources. Silver-doped zinc oxide nanoparticles (Ag-ZnO NPs), with antibacterial and antioxidant properties, were produced using Adiantum venustum extract as a green technique. Fresh A. venustum plants were gathered, then their bioactive elements were extracted with cold water and processed into nanoparticles. The main goal was to develop Ag-ZnO NPs (nanoparticles) for medical applications, especially with regard to their antifungal and antibacterial properties. Pathogens such as Fusarium oxysporum, Escherichia coli, and Staphylococcus aureus were tested against the synthesized nanoparticles. While FTIR spectroscopy revealed functional groups, X-ray diffraction validated the crystalline structure. The scanning electron microscope analysis revealed that the Ag-ZnO NPs had an average size of 30.16 nm and an irregular shape. Additionally, energy dispersive X-ray analysis) confirmed the elemental composition. The bioactive compounds present in A. venustum significantly stabilized the nanoparticles. Strong antioxidant and antibacterial activity of the Ag-ZnO nanoparticles was demonstrated. In particular, this work shows that the Ag-ZnO nanoparticles produced by green synthesis could be used in biomedical drug delivery and therapy.

Influence of Proton Irradiation on Thin Films of AZO and ITO Transparent Conductive Oxides—Simulation of Space Environment

Transparent conductive oxides are essential materials for many optoelectronic applications. For new devices for aerospace and space applications, it is crucial to know how they respond to the space environment. The most important issue in commonly used low-Earth orbits is proton radiation. This study examines the effects of high-energy proton irradiation (226.5 MeV) on thin films of aluminium-doped zinc oxide (AZO) and indium tin oxide (ITO). We use X-ray diffraction and electron microscopy observations to see the changes in the structure and microstructure of the films. The optical properties and homogeneity of the materials are determined by spectrophotometry and spectroscopic ellipsometry (SE). Analysis of the chemical states of the elements with X-ray photoelectron spectroscopy (XPS) gives insight into what proton irradiation changes at the surface of the oxides. All measurements show that ITO is less influenced than AZO. The proton energy and fluence used in this study simulate about a hundred years in low Earth orbit. This research demonstrates that both transparent conductive oxide thin films can function under simulated space conditions, with ITO showing superior resilience. The ITO film was more homogenous in terms of the total thickness measured with SE, had fewer defects and adsorbates present on the surface, as XPS analysis proved, and did not show a difference after irradiation regarding its optical properties, transmission, refractive index, or extinction coefficient.

Smart Zinc-Based Coatings with Chitosan–Alginate Nanocontainers Loaded with ZnO and Caffeine for Corrosion Protection of Mild Steel

The development of environmentally friendly materials is a subject of increasing interest in corrosion protection research. The objective of the present investigation is to propose the preparation procedure of chitosan–alginate (CHI/ALG) nanocontainers loaded with zinc oxide (ZnO) nanoparticles or combining ZnO nanoparticles with corrosion inhibitor caffeine (CAF), both suitable for incorporation into the matrix of ordinary zinc coatings on mild steel substrates. The nanocontainers were synthesized through spontaneous polysaccharide complexation in the presence of ZnO nanoparticles and CAF using a cross-linking agent, namely tripolyphosphate (TPP). Dynamic light scattering and laser Doppler velocimetry measurements are used for evaluation of the size distribution and zeta potentials of the nanocontainers, both loaded or unloaded with CAF. Using UV-spectroscopy, entrapment efficiency and release amounts of CAF are quantitatively evaluated. The nanocontainers thus obtained were incorporated into the matrices of ordinary zinc coatings via co-electrodeposition with zinc from zinc sulfate solution, aiming to improve the corrosion protection of steel in corrosive environments containing chloride ions. The surface morphology and elemental composition of the electrodeposited hybrid coatings before and after treating in the model corrosive medium of 3.5% NaCl is studied by scanning electron microscopy (SEM). The cyclic voltammetry method (CVA) is applied to characterize the cathodic (electrodeposition) and anodic (dissolution) processes. The protective characteristics of the hybrid coatings are investigated by application of potentiodynamic polarization (PDP) curves and polarization resistance (Rp) measurements after a time interval of 40 days. The obtained results indicate that both hybrid coating types could prolong the life time of mild steel in aggressive Cl− ion-containing solution, combining the protection effect of sacrificial zinc with barrier (ZnO) and active (CAF) protective effects.

Biosynthesized ZnO NPs loaded-electrospun PVA/sodium alginate/glycine nanofibers: synthesis, spinning optimization and antimicrobial activity evaluation

In this work, microalgae-based zinc oxide nanoparticles loaded with electrospun polyvinyl alcohol (PVA)/sodium alginate (SA) nanofibers were fabricated by electro-spinner. PVA/SA fibrous mats were crosslinked by citric acid, which enhanced their thermal stability and swelling behavior. Green-synthesized ZnO NPs were laboratory synthesized and characterized by FTIR, XRD, EDX, SEM, TEM and TGA analyses. Electrospinning of PVA/SA with optimized mixing ratios was further carried out with different ratios of ZnO NPs of (0.25, 0.50 and 0.75%, wt./v) to fabricate SA/PVA/ZnO composite nanofibers. The formula of NF of (SA/PVA/ZnO (0.75%) with different ratios of glycine was used for testing as topical wound dressing as promised biomaterials. Results revealed that NF formula coded AS3.3; composed of (10%PVA/1.5%SA/10%CA/0.75%ZnO/0.5% glycine), in contrast to all the other formulations examined; showed marked reduced percentages of biofilm development of both Gram-positive and Gram-negative bacteria in relation to fungal cells. The relative viable count for Bacillus cereus (98.40 ± 0.51%), Salmonella paratyphi (98.33 ± 0.79%), and Candida albicans (94.29 ± 0.76%) decreased significantly after 36-hour of incubation period with AS3.3 treatment. The obtained findings offered that the prepared composite nanofiber based on ZnO NPs and glycine; could be used as a promising and excellent antimicrobial dressing for inhibiting the microbial growth for the topical wounds healing.

Green Synthesis of Zinc Oxide Nanoparticles Including Rosehip (Rosa canina L.) Seed Extract: Evaluation of Its Characterization and Bioactivity Properties.

The use of bioactive compounds in plants as reducing, stabilizing, and capping agents in nanoparticle manufacturing is an exceptionally eco-friendly approach. This work used rosehip seed extract, acquired by automatic solvent extraction, in the microwave-assisted green production of zinc oxide nanoparticles (ZnO NPs). The total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of the extracted materials and nanoparticles (NPs) were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. The ideal synthesis parameters were established as 25mL of extract, pH 12, 360W of microwave power, and a metal salt concentration of 0.05M for a duration of 7min. The characterization of the ZnO NPs synthesized under these conditions was performed using x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy with energy-dispersive x-ray analysis (SEM-EDX), dynamic light scattering (DLS), zeta potential measurements, and UV-Vis spectrophotometry. High-purity, nano-sized, antioxidant ZnO NPs were manufactured using an ecologically friendly, sustainable, and ecological technique.