Properties Of Zinc Oxide Nanoparticles Research Articles

Investigation on the impact of cobalt doping on optical, structural and magnetic properties of zinc oxide nanoparticles

In the current article, we investigated the impact of transition metal Co2+ doping in ZnO nanoparticles and its effect on their optical, structural, and magnetic properties. The synthesized nanoparticles have the generic formula Zn1-xCoxO (x = 0.00, 0.03, 0.06, and 0.09). Single-phase hexagonal crystal structure of the synthesized nanopowder was confirmed by x-ray diffractograms. Tauc plots were used to calculate the band gap of all the samples. Multiple emission peaks were observed from the photoluminescence studies. HRTEM was employed to study the particle morphology and the size distribution. X-ray photoelectron (XPS) spectroscopy was performed to investigate the chemical composition of samples. Magnetic measurements were carried out to study the magnetic behaviour of pure and doped ZnO samples. Ferromagnetic behaviour became more prominent with the addition of Co doping, as observed by room temperature M-H plots.

Influence of Copper Doping on Structural and Opto-Electronic Properties of Zinc Oxide Nanoparticles

In this work, we elucidate the opto-electronic properties of pure zinc oxide and copper- doped zinc oxide nanoparticles prepared via the sol-gel method. Here, the main objective is to study the impact of copper doping on the crystalline structure of ZnO and to explore the composition dependent variations in opto-electronic properties. Synthesized ZnO nanoparticles were characterized by SEM, FTIR, UV–vis-nir, and Raman Spectroscopy. The structural and opto-electronic properties are further correlated using UV-vis-nir and high-resolution X- ray diffractometer data analysis. The size of synthesized nanoparticles are found in the range of 9.2 nm to 95.5 nm. Bandgaps are found both in the visible range (2.72 eV – 2.96 eV) as well as in the infrared regions (1.54 eV-1.58 eV). The transmittance of copper doped ZnO nanoparticles increases with increase in the doping concentrations.

Prunus dulcis-mediated zinc oxide nanoparticles: synthesis, characterization, and an evaluation of their biocidal properties

Use of plant extracts for synthesizing zinc oxide (ZnO) nanoparticles is gaining importance due to their easy, eco-friendly, cost effective and non-toxic nature. In this study, an economical biosynthetic approach of ZnO formation was delineated where aqueous extract of Prunus dulcis (almond) leaves has been used as reducing/capping agent followed by their characterization studies. The present study has successfully synthesized pure, highly crystalline in nature, predominantly spherical ZnO nanoparticles within the size range 71–214 nm for nanocystallites and 526 nm-2.37 μm for aggregated flower-shaped ZnO nanoparticles. Microbicidal properties of uncalcined and calcined ZnO nanoparticles were evaluated using test microbes (bacteria: E. coli, S. aureus, P. aeruginosa, B. subtilis; fungi Penicillium spp., F. oxysporum, A. flavus, R. solani). Lack of microbicidal potential was observed against all four bacteria and fungi. When tested for toxicity against HCT-116 carcinoma cells, these nanoparticles displayed non-toxic nature. This biocompatibility is influenced by physico-chemical properties of ZnO nanoparticles as well as biological properties of living cells. Thus, these ZnO nanoparticles can serve as an innocuous machinery in disease therapeutics due to the presence of their non-microbicidal and non-antineoplastic activities.

Synthesis and Characterization of Zinc Oxide Nanoparticles at Different pH Values from Clinopodium vulgare L. and Their Assessment as an Antimicrobial Agent and Biomedical Application.

The current study attempts to evaluate the formation, morphology, and physico-chemical properties of zinc oxide nanoparticles (ZnO NPs) synthesized from Clinopodium vulgare extract at different pH values and to investigate their antimicrobial and biomedical application potential. The reduction of zinc ions to ZnO NPs was determined by UV spectra, which revealed absorption peaks at 390 nm at pH 5 and 348 nm at pH 9, respectively. The spherical morphology of the nanoparticles was observed using scanning electron microscopy (SEM), and the size was 47 nm for pH 5 and 45 nm for pH 9. Fourier-transformed infrared spectroscopy (FTIR) was used to reveal the presence of functional groups on the surface of nanoparticles. The antibacterial activity was examined against Staphylococcus aureus, Streptococcus pyogenes, and Klebsiella pneumonia via the agar-well diffusion method. Comparatively, the highest activities were recorded at pH 9 against all bacterial strains, and among these, biogenic ZnO NPs displayed the maximum inhibition zone (i.e., 20.88 ± 0.79 mm) against S. aureus. ZnO NPs prepared at pH 9 exhibited the highest antifungal activity of 80% at 25 mg/mL and antileishmanial activity of 82% at 400 mg/mL. Altogether, ZnO NPs synthesized at pH 9 show promising antimicrobial potential and could be used for biomedical applications.

Effects of PVP surfactant on nanosuspension stability and optical, dielectric, and rheological properties of zinc oxide nanoparticles dispersed alcohols mixture based nanofluids

Nanofluids (NFs) are state-of-the-art engineered promising properties soft materials which found vital applications in thermal management and electrical insulation, and also gaining much attention in the advances of soft optoelectronic and microelectronic device technologies. The longer-time functionality of the NF material depends on particle suspension stability which can be maintained up to some extent with the addition of appropriate surfactants. Here, we report the promising properties of the semiconductor NF (SNF) samples consisting of a highly rich ethylene glycol (EG) mixture with glycerol (Gly) (90/10 vol%) as base fluid, zinc oxide (ZnO) nanosuspension, and poly(vinyl pyrrolidone) (PVP) surfactant. These formulated 90EG + 10Gly/x wt% (ZnO + PVP) SNFs with varying concentrations (x wt%) of ZnO and PVP are characterized by employing ultraviolet-visible (UV–Vis) spectrophotometer (wavelength range 200–800 nm), precision inductance-capacitance-resistance (LCR) meter (frequency range 50 Hz to 1 MHz), and rotational rheometer (shear rate range 13–132 s−1). The UV–Vis absorbance spectra, recorded on the freshly prepared and aged SNF samples, confirmed that the added PVP enhances longer time suspension stability for ZnO nanoparticles in the H-bonded 90EG + 10Gly viscous base fluid, and also promoted the photosensitivity, electronic transition, and radiation blocking performance of these materials. The dielectric spectra revealed a huge contribution of the electrode and interfacial polarization processes to the dielectric permittivity of the SNFs at low frequencies and their dynamics is explored from the intense relaxation peaks observed in the loss angle tangent spectra. The higher experimental frequency range dielectric permittivity remains frequency independent and it is marginally affected by the ZnO and PVP concentrations in these SNFs, at 298.15 K. The electric modulus and impedance spectra of these SNFs are also provided and analyzed for the charge conductivity and interfacial relaxation processes. The ac electrical conductivity of these materials obeys the power law behaviour along with the dc conductivity part in the range from 5.4 to 6.8 × 10–7 S⋅cm−1. The rheological measurements on these SNFs, in the 303.15 K to 323.15 K, categorized them as Newtonian-type fluids with a considerable increase in dynamic viscosity by PVP dissolution. These materials showed the Arrhenius behaviour of viscous flow having activation energies in the range of 25–27 kJ⋅mol−1. The experimental results of various techniques on these green-formulated SNFs revealed their multifunctionality with great potential for the future generation of soft device technologies, in addition to highlighting their current applications of manageable heat transfer in the flow systems.

ZnO Nanoparticles Impact on Organ Systems in Rats: A Comprehensive Exploration of Diverse Exposure Pathways

The synthesis and utilization of nanomaterials with precise spatial dimensions on the nanoscale are pivotal in the field of nanotechnology. In recent years, metal oxide nanoparticles have become increasingly common, raising concerns in the scientific community and the general public about their potential harm to the environment and living organisms. Despite this, there are still significant debates and misconceptions regarding the adverse effects and mechanisms of these nanoparticles. To facilitate their safe and responsible use, it is imperative to gain a comprehensive understanding of their adverse effects. This review aims to provide an overview of the biological fate of zinc oxide (ZnO) nanoparticles in rats through various exposure routes, shedding light on their toxicological consequences and the underlying mechanisms of toxicity. Despite the fact that ZnO nanoparticles have a propensity to target organs such as the liver, kidneys, and lungs, it is noteworthy that higher concentrations of zinc are detected in these tissues following exposure via various routes. The liver plays a central role in the metabolism of ZnO nanoparticles. Multiple exposure routes, including oral, intraperitoneal, intravenous, and intratracheal routes, have been shown to induce liver damage, along with adverse effects on the kidneys and lungs, when exposure occurs via airways. A significant toxicological mechanism associated with ZnO nanoparticles involves the generation of reactive oxygen species (ROS) and the subsequent initiation of oxidative stress. ROS production can result from both the excessive release of Zn+2 ions and the particulate effect stemming from the semiconductor or electronic properties of ZnO nanoparticles. The potential for surface coatings and modifications holds the promise of further expanding the range of biomedical applications for ZnO nanoparticles, opening up exciting possibilities for futuristic medical treatments, including targeted drug delivery, advanced imaging techniques, and diagnostics.

Zinc Oxide Nanoparticles as The Anti-Bacterial Tool: In Vitro Study

A new class of metal oxide nanoparticles has recently been found to be widely used in various health-related research. In particular, Zinc Oxide (ZnO) nanoparticles have occupied a prominent status due to their unique chemical and electrical properties. In our study, we aim to reveal the anti-bacterial effect of these nanoparticles. The antibacterial activity of zinc oxide (ZnO) nanoparticles against isolated pathogenic Escherichia coli (strain MTCC 723) was determined from our study. The antimicrobial properties of ZnO were also determined by adjusting the concentration of ZnO nanoparticles. By sonicating ZnO nanoparticles in water, a homogenized suspension was created, and the infusion was made at 50 – 150g/ml concentrations. Anaerobic conditions were used to culture the pathogenic strain of microbial species, and DNA was extracted using an extraction kit. For testing, equalized standard dilutions of cultivated bacteria were utilized. The anti-bacterial capabilities of zinc oxide (ZnO) nanoparticles against bacteria were measured using spectroscopic and diffusion experiments. ZnO nanoparticles with a diameter of 50 nm and a concentration of 150 g/ml lysed Escherichia coli DNA and cells. According to the findings, ZnO nanoparticles with a concentration of 150 g/ml had significantly more vigorous activity against Escherichia coli. The agar diffusion method was used to quantify the anti-bacterial activity of zinc oxide (ZnO) and the quality and amount of DNA extraction in the presence of ZnO nanoparticles (ZnO). The pathogenic Escherichia coli cells and the gene DNA are killed at the optimal dose. This study aims to know the anti-bacterial properties of ZnO nanoparticles against pathogenic Escherichia coli cells. The optimization of ZnO nanoparticles concentration against its effect on Escherichia coli cells is the next aim of this study.

The effect of calcination temperatures on the structural and optical properties of zinc oxide nanoparticles and their influence on the photocatalytic degradation of leather dye

The challenge of dealing with synthetic dye pollution in waste from the leather industry requires continual research and development. Although numerous dyes used in the textile, food, and other industries have been found to be degraded by photocatalyst based on zinc oxide nanoparticles (ZnO NPs), no thorough studies on the degradation of leather dye from dye-containing wastewaters from tanneries have been reported to date. Hence, this study investigates the efficient photocatalytic destruction of leather dye using ZnO NPs produced by chemical precipitation method. The influence of calcination temperatures ranging from 400 to 600 °C on the structural and optical characteristics of ZnO NPs was investigated. XRD examination revealed an increase in crystallite size as the calcination temperature increased, presumably due to the merger of smaller crystallites into larger ones. Meanwhile, the polycrystalline and wurtzite structure of the synthesized ZnO NPs was observed, with particle diameters ranging from 40 to 90 nm and an average size of around 62 nm. UV–vis spectra revealed a decrease in energy band gap (3.15 to 3.05 eV), which was ascribed to an increase in crystallite size produced by higher calcination temperature from 400 to 600 °C. The photocatalytic degradation of leather dye was studied further. It has been demonstrated that ZnO NPs synthesized at a calcination temperature of 400 °C can remove 90% of the leather dye in 30 min. The dynamics of deterioration were also studied. It was discovered that the degradation of leather dyes best fitted the pseudo-first-order kinetics, with superoxide ions being the most likely species.

Multi Self-cleaning Properties of Zinc Oxide Nanoparticles/ Polydimethylsiloxane (ZnO/PDMS) Composite on Polyester Textile

Self-cleaning textiles can be divided into three categories, which are the physical, chemical, and biological self-cleaning types. Physical self-cleaning refers to the lotus effect, which relates to the hydrophobic properties of the textile. Chemical self-cleaning is the degradation of color stains, discolored solutions and other organic species that come into contact with textiles. The last is biological self-cleaning, which is the ability to kill bacteria that become attached to the textiles. In this research, the development of all three self-cleaning properties of polyester textile coated with zinc oxide nanoparticles/ polydimethylsiloxane (ZnO/ PDMS) composite was focused. The ZnO nanoparticles were synthesized by a hydrothermal process, which involved blending PDMS with various concentrations of ZnO nanoparticles. The polyester textile was coated with ZnO/ PDMS composite solution via a dip coating technique done with various dipping times. The lotus effect, which depends on hydrophobic properties, was analyzed by water contact angle measurement. The chemical self-cleaning of the polyester textile was examined by photocatalytic methylene blue dye degradation with UV-Vis spectrometry. The inhibition zone of antibacterial activity was tested via disc diffusion technique. From these results, it was found that the polyester textile coated with ZnO/PDMS composite demonstrated all self-cleaning properties, physical, chemical and biological, in a significantly way.

Biodegradable PLA-ZnO nanocomposite biomaterials with antibacterial properties, tissue engineering viability, and enhanced biocompatibility

Polylactic acid (PLA) is a well-known biomaterial on account of its biocompatibility and biodegradability. Zinc oxide (ZnO) nanofillers may endow PLA with advantageous antibacterial and tissue regenerative properties, but may also compromise the biocompatibility of PLA. Several strategies have been developed to improve the biomedical practicality of such composites. The importance of surface properties on amplifying the therapeutic properties and safety of a material enables two potential strategies: (i) surface modification of ZnO nanoparticles, and (ii) surface engineering of the PLA/ZnO composites. Moreover, the controllable biodegradation of PLA allows a third possible strategy: (iii) biodegradation-controlled release of ZnO. The first part of this review introduces the controllable degradation of PLA and the mechanisms of therapeutic properties and cytotoxicity of ZnO. Following this, the paper highlights current research trends regarding the biomedical application of PLA-based ZnO nanocomposites. The final section of this review discusses the potential use of ZnO in tuning the degradation rate of PLA, and the possibility of manipulating the surface properties of ZnO nanoparticles and PLA/ZnO composites in order to optimize the therapeutic properties and safe usage of PLA/ZnO composites in the biomedical field.

Antifungal Properties of Zinc Oxide Nanoparticles on Candida albicans

This paper reports the antifungal properties of zinc oxide nanoparticles (ZnO NPs) on Candida albicans ATCC 1023 through the study of growth inhibitory effects of ZnO NPs on C. albicans and the effect of the nanoparticles on the surface of C. albicans. The growth inhibitory effects of ZnO NPs (5, 10, 20, 40, 80, and 160 µg/mL) on C. albicans at 24 h were determined through the reduction in suspension turbidity and colony count. Fourier transform infrared (FTIR) analysis was carried out to establish the functional groups associated with the interaction of ZnO NPs on the yeast cell wall, while scanning electron microscopy (SEM) with energy dispersive X-ray (SEM-EDX) analysis was utilised to determine the surface accumulation of ZnO NPs on the yeast cells and the consequential morphological alterations on C. albicans. The results exhibited a significant (p < 0.05) growth inhibition for all tested concentrations except for 5 µg/mL of ZnO NPs at 24 h as compared to negative control. FTIR analysis revealed the possible involvement of alcohol, amide A, methyl, alkynes, amide I and II, and phosphate groups from the cell wall of C. albicans in the surface interaction with ZnO NPs. Finally, SEM-EDX revealed a considerable accumulation of ZnO NPs on the yeast cells and consequential morphological alterations on C. albicans, including the damage of hyphae, pitting of the cell wall, invagination, and rupture of the cell membrane. The current study demonstrated that ZnO NPs possess antifungal properties against C. albicans in a dose-dependent manner, and the surface interaction of ZnO NPs on fungal cells caused alterations in cell membrane integrity that might have resulted in cell death.

Nonlinear Optical Properties of Zinc Oxide Nanoparticle Colloids Prepared by Pulsed Laser Ablation in Distilled Water

The nonlinear optical properties of zinc oxide nanoparticles (ZnONPs) in distilled water were measured using a femtosecond laser and the Z-scan technique. The ZnONPs colloids were created by the ablation of zinc bulk in distilled water with a 532 nm Nd: YAG laser. Transmission electron microscopy, an ultraviolet-visible spectrophotometer, and atomic absorption spectrophotometry were used to determine the size, shape, absorption spectra, and concentration of the ZnONPs colloids. The nonlinear absorption coefficient and nonlinear refractive index were measured at different excitation wavelengths and intensities. The nonlinear absorption coefficient of the ZnONPs colloids was found to be positive, caused by reverse saturable absorption, whereas the nonlinear refractive index was found to be negative due to self-defocusing in the ZnONPs. Both laser parameters, such as excitation wavelength and input intensity, and nanoparticle features, such as concentration and size, were found to influence the nonlinear optical properties of the ZnONPs.

Hydrothermal Synthesis of Zinc Oxide Nanoparticles Using Different Chemical Reaction Stimulation Methods and Their Influence on Process Kinetics.

The aim of this work was to study the effect of the applied chemical reaction stimulation method on the morphology and structural properties of zinc oxide nanoparticles (ZnONPs). Various methods of chemical reaction induction were applied, including microwave, high potential, conventional resistance heater and autoclave-based methods. A novel, high potential-based ZnONPs synthesis method is herein proposed. Structural properties-phase purity, grain size-were examined with XRD methods, the specific surface area was determined using BET techniques and the morphology was examined using SEM. Based on the results, the microwave and autoclave syntheses allowed us to obtain the desired phase within a short period of time. The impulse-induced method is a promising alternative since it offers a non-equilibrium course of the synthesis process in an highly energy-efficient manner.

The photocatalytic, cytotoxicity, and antibacterial properties of zinc oxide nanoparticles synthesized using Trigonella foenum-graecum L extract.

In this study, the manufacture of zinc oxide nanoparticles (ZnO-NPs) was completed via the sol-gel method with Trigonella foenum-graecum L extract for the first time to function as the stabilizing and reducing agent. The obtained product was investigated by various analyzing procedures such as TGA/DTG, FT-IR, UV-Vis, XRD, and EDX/FESEM. The calcination of our product was conducted at temperatures of 400, 500, and 600°C. In conformity to the XRD pattern, heightening the temperature of calcination caused an enlargement in the size of nanoparticles. The photocatalytic performance of ZnO-NPs was evaluated to degrade methylene blue and Eriochrome black T (EBT) dyes under UV light, which resulted in a degradation percentage of about 96% and 94%, after 90min, respectively. There has been some evidence suggesting that the green synthesis of ZnO-NPs has increased their use in medicine. The outcomes of examining the cytotoxicity effect of this product against the Huh-7 cell line by the performance of the MTT assay were indicative of an IC50 of around 62.5µg/mL. Finally, according to the results of the broth microdilution method, which was performed to assess the antibacterial activity of ZnO-NPs towards gram-positive and gram-negative bacteria, the value of MIC was in the range of 31 to 125µg/mL. The obtained results from biological studies confirm the antibacterial and anticancer properties of ZnO-NPs, which are promising for applying NPs in medical fields.

The effect of magnesium doping concentration on the structural and optical properties of zinc oxide nanoparticles

In this study, the optical and structural properties of Magnesium doped Zinc Oxide (Zn1-xMgxO) nanoparticles (x = 1%, 3%, and 5%) were examined. The synthesis was carried out at 300 oC by using a simple co-precipitation method. The structural samples were used to characterize the synthesized nanoparticles by using Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). Energy Dispersive X-Ray spectroscopy (EDX) was used to determine the chemical composition of the samples. Furthermore, UV-Vis spectroscopy was conducted to study our samples’ optical characteristics. As per XRD analysis, both pure and Mg doped ZnO samples possess wurtzite structure. The particle size was revealed to decrease significantly with Mg concentration, from 36 nm for pure sample to 23.87 nm with 5% Mg. In comparison to ZnO, the XRD pattern of Mg-doped ZnO shows a peak shift towards lower 2θ values. As a result of deformation of crystal structure caused by integrated Mg+2 ions onto Zn+2 sites. SEM images of synthesized samples reveal that the nanoparticles possess sheet, spherical and rod like morphologies for different values of x. The EDX analysis verifies the purity of samples within the detection limits. According to optical absorption spectra obtained from UV-Visible spectroscopy in the 200nm to 1000nm range affirmed that as Mg concentration increased, the band gap increased from 3.37 eV for pure sample to 3.74 eV with 5% Mg. The UV-Visible spectra of pure ZnO and Mg-doped ZnO samples also exhibit distinct peaks in the UV region at 335 nm, 311 nm, 310.6 nm, and 310 nm. Across the spectra of pure and Mg-doped ZnO samples, the UV peak is attributed to free exciton transitions, whereas, in the spectra of Mg-doped ZnO UV absorbance peak in the visible region is attributed to the radiative transitions of electrons captured at oxygen vacant sites with holes trapped at singly ionized oxygen vacancies.

Effect of annealing in argon atmosphere on the properties of zinc oxide nanoparticles doped with Mn(II) and Co(II) ions prepared in solvothermal synthesis

Methods of preparation and application of zinc oxide nanoparticles doped with Mn(II) and Co(II) ions are presented and discussed in the paper. Part one shows the results of the solvothermal synthesis of zinc oxide nanoparticles doped with Mn(II) and Co(II) ions. The effect of process parameters on the properties of doped nano zinc oxide has been identified. We also examined the impact of annealing in argon atmosphere of doped zinc oxide nanoparticles on physicochemical properties. Morphology analysis was performed using scanning microscopy and molecular analysis was performed using by inductively coupled plasma - optical emission spectrometry. The zeta potential was measured for samples annealed in argon atmosphere and for samples not annealed. Phase analysis was performed by x-ray diffraction. Based on this analysis, the lattice parameters were determined.

Enhanced antibacterial property of zinc oxide nanoparticles by incorporation of graphene oxide

Enhanced antibacterial property of zinc oxide nanoparticles by incorporation of graphene oxide

Effect of Optimized Precursor Concentration, Temperature, and Doping on Optical Properties of ZnO Nanoparticles Synthesized via a Green Route Using Bush Tea (Athrixia phylicoides DC.) Leaf Extracts.

Nanoparticles possess several properties, such as antimicrobial, anti-inflammatory, wound healing, catalytic, magnetic, optical, and electronic properties, that have allowed them to be used in different fields. Among them, zinc oxide (ZnO) has received copious consideration due to its technological and medicinal applications. Plant-mediated synthesis of ZnO nanoparticles has provided a cost-effective and eco-friendly method. Therefore, the objective of the study is to assess the effect of the precursor concentration and silver and cerium doping on the optical properties of ZnO nanoparticles synthesized via a green process using bush tea leaf extract as the chelating agent. Zinc nitrate hexahydrate was used as the precursor. Quasi-spherical-shaped ZnO nanoparticles were obtained with an average crystallite size ranging between 24.53 and 63.02 nm. The crystallite size was found to decrease with the increase of precursor concentration at 43.82 nm (0.05 g), 37.25 nm (0.10 g), 26.53 nm (0.50 g), and 24.53 nm (1 g); thereafter, the size increases with an increase in precursor concentration. The optimum precursor concentration was 1 g with the smallest grain size and a high purity level. The increase in annealing temperature induced an increase in the crystallite size of ZnO nanoparticles from 24.53 nm (600 °C) to 34.24 nm (800 °C), however, increasing the level of purity of the nanopowders. The band gap energies were 2.75 and 3.17 eV as calculated using the Tauc plot with variations due to the precursor concentrations. Doping with both silver and cerium increased the band gap of ZnO nanoparticles up to 3.19 eV and the increase in annealing temperature slightly augmented the band gap energy from 3.00 and 3.16 eV, respectively. Hence, doping with Ag and Ce induced the formation of nanorods at higher concentrations. This study successfully demonstrated that the natural plant extract of bush tea can be used in the bioreduction of zinc nitrate hexahydrate to prepare pure ZnO nanoparticles, thus extending the use of this plant to the nano producing industry.

Innovative Investigation of Zinc Oxide Nanoparticles Used in Dentistry

Dental caries is a major lifestyle concern as dental components affect the face of an individual. The issue of tooth decay occurs in every age group throughout the globe. Researchers are probing incipient implements and techniques to develop filling agents for decayed teeth. Zinc oxide (ZnO) powder is utilized mostly as a filling agent. Nanotechnology enhanced the efficiency of compounds of metal oxides utilized for dental caries. The present study aims to investigate the properties of ZnO nanoparticles (NPs) synthesized chemically (using ZnCl2 and NaOH) as well as biologically (using aqueous leaf extract of Murraya paniculata). The XRD patterns confirm that ZnO NPs have a hexagonal crystalline structure with particle sizes of 47 nm and 55 nm for chemically and biologically synthesized NPs, respectively. The FE-SEM data confirm the nanorod and spherical/cubical shape morphologies for the chemically and biologically synthesized ZnO NPs, respectively. FTIR data show the peaks between 4000 and 450 cm−1 of the functional groups of –OH, C-O, –C-H-, and Zn-O bonds. The UV–Vis absorption study indicates a peak around 370 nm and a hump around 360 nm corresponding to the chemically and biologically synthesized ZnO NPs, respectively. An antibacterial bioassay was performed and compared with commercially available ZnO bulk powder against tooth decaying pathogens, viz., Streptococcus mutans, Staphylococcus aureus, E. coli, and Lactobacillus fermentum, and found that both ZnO NPs had results closer to those of the standard drug (rifampicin). Thus, the synthesized ZnO NPs may be utilized as nano-drugs for the application of tooth decaying filling agents. Even biologically synthesized ZnO NPs may be considered more environmentally friendly and less toxic to human health concerns.

Fabrication, characterization and antibacterial properties of ZnO nanoparticles decorated electrospun polyacrylonitrile nanofibers membranes

Zinc oxide (ZnO) was widely used in antibacterial applications due to the excellent physicochemical properties and unique bioactivities. However, powdery ZnO could give rise to further problems, such as the agglomeration, easy deactivation, the difficult recovery during the used process, and so on. In this study, polyacrylonitrile nanofiber membranes (PAN NFMs) had been electrospun and reinforced with organic Hectorite (OHec). Further, prepared NFMs decorated with ZnO via surface modification technique, denoted as ZnO-g-PAN NFMs. The characterizations of pure PAN and ZnO-g-PAN NFMs were investigated by means of FESEM, FTIR, XRD and TG, furthermore, antibacterial properties were also analyzed. The results indicated that the surface morphology of ZnO-g-PAN NFMs became uneven, rough and irregular compared with raw PAN. The incorporation of ZnO and OHec in the fibers mainly enhanced the mechanical properties of NFMs. The hydrophilicity and surface roughness of NFMs increased with increasing of the ZnO concentration. In particular, ZnO-g-PAN NFMs exhibited excellent antibacterial activities, which was approved by the fact that they revealed the antibacterial rates of 97.7 % against Escherichia coli (E. coli) and 98.2 % against Staphylococcus aureus (S. aureus). Further, NFMs showed good cytocompatibility with L929 cells. These results demonstrated that ZnO-g-PAN NFMs would have a great potential for antibacterial applications.