Antibacterial Activity Of ZnO Nanoparticles Research Articles

Reconciling the monodispersity of bioinspired ZnO nanoparticles on palygorskite nanorods for a well-balanced antibacterial effect and biocompatibility

In order to study the effect of support on the antibacterial activity of ZnO nanoparticles formed in the bioinspired process, a series of palygorskite (Pal) supported ZnO nanocomposites (ZnO/Pal) were fabricated using licorice extract and the antibacterial actions related to the structure of loaded ZnO nanocomposites was elucidated. The samples were characterized by the means of UV–vis, XRD, TEM, FTIR, TG and XPS, and the antibacterial properties were determined by the agar disk diffusion assay and colony counting assay. The structural analysis revealed that pure ZnO nanoparticles with average grain diameter of about 11 nm were formed in the green bioinspired process and anchored on the surface of Pal nanorods. And with Pal amount decreasing (ZnO loading increased from 10 % to 40 %), the ZnO NPs aggregated intensify and promoted the assembling of ZnO/Pal nanorods into bigger clusters, and four kinds of ZnO/Pal with different morphologies were formed. Among them, 20 % loading of ZnO/Pal showed antibacterial activity comparable to that of 30 % and better than that of 40 %, because ZnO nanoparticles in 20 % ZnO/Pal are monodispersed on Pal nanorods that maintained full exposure and high activity of ZnO NPs as well as better killing efficiency than those with clustered ZnO NPs. The mechanism analysis demonstrated that the bacteria-adsorbed capacity of Pal and the enhanced contact of small ZnO NPs with bacterial cells leading to intensified membrane-damage and intracellular metabolic imbalance are the main bactericidal actions of ZnO/Pal nanocomposites. This study first gave insight into the structure-related antibacterial behavior of ZnO/Pal nanocomposites, and provides an improved green way to design efficient clay-supported ZnO antibacterial nanomaterials.

Biosynthesis and antibacterial activity of ZnO nanoparticles using Buchanania obovata fruit extract and the eutectic-based ionic liquid

The fruit extract of Buchanania obovata and the eutectic-based ionic liquid were utilized, in an eco-friendly, inexpensive, simple method, for synthesizing zinc oxide nanoparticles (ZnO NPs). The influence of the reducing, capping and stabilizing agents, in both mediums, on the structure, optical, and morphological properties of ZnO NPs was extensively investigated. The surface plasmon resonance peaks were observed at 340 nm and 320 nm for the fruit-based and the eutectic-based ionic liquid mediums, respectively, indicating the formation of ZnO NPs. XRD results confirmed the wurtzite structure of the ZnO NPs, exhibiting hexagonal phases in the diffraction patterns. The SEM and TEM images display that the biosynthesized ZnO NPs exhibit crystalline and hexagonal shape, with an average size of 40 nm for the fruit-based and 25 nm for the eutectic-based ionic liquid. The Brunauer–Emmett–Teller (BET) surface area analysis, revealed a value ∼13 m2 g−1 for ZnO NPs synthesized using the fruit extract and ∼29 m2 g−1 for those synthesized using the eutectic-based ionic liquid. The antibacterial activity of the biosynthesized ZnO NPs was assessed against clinically isolated Gram-negative (E. coli) and Gram-positive (S. aureus) bacterial strains using the inhibition zone method. The ZnO NPs produced from the eutectic-based ionic liquids confirmed superior antibacterial activity against both S. aureus and E. coli compared to those mediated by the utilized fruit extract. At a concentration of 1000, the eutectic-based ionic liquid mediated ZnO NPs displayed a maximum inhibition zone of 16 mm against S. aureus, while against E. coli, a maximum inhibition zone of 15 mm was observed using the fruit extract mediated ZnO NPs. The results of this study showed that the biosynthesized ZnO NPs can be utilized as an efficient substitute to the frequently used chemical drugs and covering drug resistance matters resulted from continual usage of chemical drugs by users.

Effect of pH, Amount of Metal Precursor, and Reduction Time on The Optical Properties and Size of Zinc Oxide Nanoparticles Synthesized Using Aqueous Extract of Rhizomes of Acorus calamus

Nanoparticles possess various unique characteristics compared to the corresponding bulk materials. Large band gap, non-toxic nature, and multi-applicability are the worthwhile characteristics of zinc oxide to be synthesized and studied. The size of nanoparticles can be controlled by varying the different experimental conditions. This paper reports the synthesis of zinc oxide nanoparticles by using an aqueous extract of rhizomes of Acorus calamus, where the bio-components present in aqueous extract acted as reducing agents. The size and band gap energy of zinc oxide nanoparticles were studied by varying different parameters such as pH, concentration of the metal precursor, and reduction time. The variations in the size of nanoparticles were studied by UV-visible spectroscopy. FTIR showed phenolic compounds, primary amines, and amides (proteins/enzymes) as the functional groups responsible for the reduction of metal precursors to form nanoparticles. The surface morphology of nanoparticles was studied by FE-SEM image. The FE-SEM image displayed the formation of various shapes and agglomeration of the nanoparticles. XRD pattern revealed that the average size of zinc nanoparticles is 10 nm. In vitro antibacterial activity of ZnO nanoparticles has been assayed against gram-positive and gram-negative bacteria. The growth inhibitory activity of nanoparticles against different bacterial pathogens has also been determined

Investigating the effect of acidic and basic precipitation on the antibacterial activity of ZnO nanoparticles against Gram-negative and Gram-positive bacteria.

In the present work, acidic (direct) and basic precipitation (indirect) methods were used to demonstrate the influence of the mode of precipitation on the structural properties of ZnO nanoparticles (NPs). Four samples of ZnO nanoparticles were prepared, two samples via each mode of precipitation. DZOa and IZOa were the aged samples prepared via acidic and basic precipitation methods, and DZOwa and IZOwa were processed without aging. Both precipitation processes were carried out without using any surfactant reagents. Zinc hydroxide precipitate, which was formed during the basic precipitation method, could be critical in deciding the properties of ZnO NPs, unlike zinc hydroxide formed during acidic precipitation. Aging of zinc hydroxide, synthesised by basic precipitation method for 48 hours was found to be an added advantage in controlling the properties of ZnO NPs. The influence of the mode of precipitation on the structural properties and antibacterial activity of ZnO NPs against Gram-positive and Gram-negative bacterial strains was tested. The antibacterial activity of all four ZnO NPs was analysed via zone of inhibition measurements at a concentration dose of 200 μg ml-1. IZOa nanoparticles prepared using the basic precipitation method showed a higher antibacterial activity against three Gram-negative and one Gram-positive strains, namely, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. DZOa nanoparticles synthesized through acidic precipitation showed relatively high antibacterial activity against Salmonella typhimurium, a Gram-negative strain. ZnO NPs prepared without aging, IZOwa and DZOwa, showed a higher antibacterial activity against E. coli and Bacillus sp. strains, respectively. All ZnO NPs were characterized via UV-visible, FTIR, XRD, and HRSEM techniques.

Zea mays-mediated fabrication and characterization of zinc oxide nanoparticles with enhanced antibacterial and antioxidant properties

This study presents the synthesis of zinc oxide nanoparticles (ZnO-NPs) using Zea mays leaf extract as a natural reducing and stabilizing agent. The synthesized ZnO-NPs were comprehensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR). XRD analysis confirmed the crystalline nature of the NPs, while SEM revealed their morphology and size distribution. EDX confirmed the elemental composition of the synthesized ZnO-NPs, and FTIR provided insights into the functional groups involved in NPs formation. The antibacterial activity of ZnO-NPs was evaluated against a selected bacterial strain using the agar well diffusion method. The results demonstrated a zone of inhibition around the wells containing ZnO-NPs, indicating their potential antibacterial efficacy. The antioxidant activity of ZnO-NPs was assessed by their ability to scavenge ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)) free radicals. It was found that the scavenging activity got increased with the concentration of ZnO-NPs, indicating their potential as antioxidants.

Papaya peel extract-mediated green synthesis of zinc oxide nanoparticles and determination of their antioxidant, antibacterial, and photocatalytic properties.

This study describes an effective and eco-friendly approach to the synthesis of zinc oxide nanoparticles (ZnONPs) utilizing papaya fruit peel extract (PPE). The structural evaluation and morphological features of synthesized ZnONPs were examined using various physicochemical analyses. The formulated ZnONPs were spherical to hexagonal in shape with ⁓ 170nm in diameter. ZnONPs exhibited improved antioxidant potential in terms of DPPH radical scavenging activity (IC50 = 98.74µg/ml) and ferric-reducing potential compared with PPE. The antibacterial activity of ZnONPs was measured against pathogenic strains of Salmonella typhi, Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. The biosynthesized ZnONPs showed potential antibacterial efficacy against all microbes. In addition, ZnONPs exhibited potential photocatalytic activity in rhodamine B degradation in the presence of sunlight. The results indicated that papaya peels, which are these fruit wastes, could be helpful for the green synthesis of ZnONPs with good dose-responsive antioxidant, antibacterial, and photocatalytic activities.

Structural, morphological, optical and biomedical applications of Berberis aristata mediated ZnO and Ag-ZnO nanoparticles

Herein, we prepared the zinc oxide (ZnO) and silver doped zinc oxide (Ag-ZnO) nanoparticles (NPs) using Berberis aristata plant extract as a reducing, capping and stabilizing agent. The x-ray diffraction (XRD) pattern confirms the formation of pure hexagonal wurtzite structure for both the samples with P4mm space group. The crystallite size reduces from 21.313 nm to 18.179 nm with the Scherrer technique with doping of Ag ions on ZnO NPs, while the Williamson Hall (WH) approach likewise demonstrates a decrease in crystallite size from 26.602 nm to 21.522 nm. The lattice strain increases from 0.0031 to 0.0064, indicating the presence of Ag-ions in the crystal lattice of ZnO NPs. For both samples, the metal-oxygen bond formation is supported by the Fourier Transform Infrared (FTIR) spectra. For ZnO, the peak in the UV-visible spectrum is approximately around 365 nm, but for Ag-ZnO, two peaks are observed around 235 nm and 360 nm. With the Ag doping, the bandgap increases from 3.01 eV to 3.02 eV. Transmission Electron Microscopy (TEM) micrographs show the formation of crystalline particles and Field Emission Scanning Electron Microscopy (FESEM) pictures show the formation of aggregated NPs with a spherical shape. Energy Dispersive x-ray Spectroscopy (EDX) and x-ray Photoelectron Spectroscopy (XPS) demonstrate the chemical purity of both the samples. The antibacterial activity of ZnO NPs was highest against Staphylococcus aureus i.e., 15 ± 0.53 mm, whereas, for Ag-ZnO NPs the highest activity was against Salmonella typhi i.e., 19 ± 0.53 mm.

Lepidium sativum Seed Extract-Mediated Synthesis of Zinc Oxide Nanoparticles: Structural, Morphological, Optical, Hemolysis, and Antibacterial Studies.

Nanomaterials have unique physicochemical properties compared to their bulk counterparts. Besides, biologically synthesized nanoparticles (NPs) have proven superior to other methods. This work aimed to biosynthesize zinc oxide (ZnO) NPs using an aqueous extract of Lepidium sativum seed. The obtained ZnO NPs were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared, and ultraviolet-visible spectroscopy. The in vitro antibacterial activity of ZnO NPs against Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria was assessed using the disk diffusion technique. The hemolytic impact was quantified spectrophotometrically. The results indicated a 24.2 nm crystallite size, a hexagonal structure phase, and a 3.48 eV optical bandgap. Antibacterial studies revealed a dose-dependent response with comparable activity to the standard drug (gentamicin) and higher activity against S. aureus than E. coli, e.g., the zone of inhibition at 120 mg/mL was 23 ± 1.25 and 16 ± 1.00 mm, respectively. The hemolysis assay showed no potential harm due to ZnO NPs toward red blood cells if utilized in low doses. As a result, it could be concluded that the reported biogenic method for synthesizing ZnO NPs is promising, resulting in hemocompatible NPs and comparable bactericidal agents.

Antibacterial Activity of ZnO Nanoparticles in a Staphylococcus-aureus-Infected Galleria mellonella Model Is Tuned by Different Apple-Derived Phytocargos.

This research investigates pH changes during the green synthesis of ZnO nanoparticles (NPs) and emphasises its importance in their physicochemical, antibacterial, and biological properties. Varying the synthesis pH from 8 to 12 using "Bravo de Esmolfe" apple extracts neither affected the morphology nor crystallinity of ZnO but impacted NP phytochemical loads. This difference is because alkaline hydrolysis of phytochemicals occurred with increasing pH, resulting in BE-ZnO with distinct phytocargos. To determine the toxicity of BE-ZnO NPs, Galleria mellonella was used as an alternative to non-rodent models. These assays showed no adverse effects on larvae up to a concentration of 200 mg/kg and that NPs excess was relieved by faeces and silk fibres. This was evaluated by utilising fluorescence-lifetime imaging microscopy (FLIM) to track NPs' intrinsic fluorescence. The antibacterial efficacy against Staphylococcus aureus was higher for BE-ZnO12 than for BE-ZnO8; however, a different trend was attained in an in vivo infection model. This result may be related to NPs' residence in larvae haemocytes, modulated by their phytocargos. This research demonstrates, for the first time, the potential of green synthesis to modulate the biosafety and antibacterial activity of NPs in an advanced G. mellonella infection model. These findings support future strategies to overcome antimicrobial resistance by utilizing distinct phytocargos to modulate NPs' action over time.

Photocatalytic and antibacterial activities of ZnO nanoparticles synthesized from Lupinus albus and Lupinus pilosus plant extracts via green synthesis approach

Photocatalytic and antibacterial activities of ZnO nanoparticles synthesized from Lupinus albus and Lupinus pilosus plant extracts via green synthesis approach

Effect of Fe doped and capping agent – Structural, optical, luminescence, and antibacterial activity of ZnO nanoparticles

Zinc oxide nanoparticles (ZnO NPs) are indispensable materials for spectral and optical phenomena, prepared by a chemical precipitation method. We studied their properties resulting from different dopants in the nanoscale. The samples' structure, texture, energy band, and photoluminescence were examined using XRD, TEM, FTIR, PL, and UV–VIS spectroscopy. XRD shows the single hexagonal Wurtzite with crystallite sizes from 10.1 to 17.8 nm and the spherical shape particles. The octahedral sites at 470–489 cm−1 and the tetrahedral sites at 616 cm−1 were observed in the FTIR studies. PL showed a wider bandgap, better UV emission, and decreased defect density of the Fe doped than that of the pristine one. Fe-doped ZnO NPs are more active than pristine ZnO NPs for their quenching or absorbing properties, indicating their antibiotic properties.

Synthesis of ZnO nanoparticles from zinc acetate dihydrate – An environmental friendly technique

The present work describes a plant-mediated method for the synthesis of Zinc Oxide (ZnO) nanoparticles. The native medicinal herb Pistia Stratiotes plant extract and the Zinc Acetate derivative were used to successfully produce the ZnO nanoparticles (NPs). Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy were used to analyze the ZnO nanoparticles that were produced. The morphology and shape of the NPs were examined using SEM. The functional group present in the leaf extract was determined by FTIR spectroscopy and the CH stretching and NH bonding of ZnO were also observed. The antibacterial activity of ZnO NPs was examined against gram-negative and gram-positive bacterial strains such as Klebsiella Pneumoniae and Bacillus Subtilis in different solvent extracts. The synthesized ZnO NPs exhibited significant inhibitory activity against the pathogenic bacterial strains.

Antibacterial activity of ZnO nanoparticles against diverse bacterial strains

To control microbial infection, a number of novel tactics have been used. Increasingly, a new class of materials called metal oxide nanoparticles is being used. being acknowledged for its potential in health-related applications and research. According to recent investigations, metal oxides Nps that have been properly synthesized have strong antibacterial activity. Zinc oxide (ZnO) offers an array of exceptional advantages that make it a prized material across various fields. With its affordable cost, excellent gas sensing capabilities, and potent photocatalytic activity, ZnO proves to be a valuable asset in numerous applications. Its antimicrobial qualities ensure effective defense against harmful microorganisms, while the ability to create structures with unique optical features and act as a catalyst in small quantities adds to its versatility. Moreover, being non-toxic, ZnO is environmentally friendly and safe for use, making it an all-round remarkable substance with diverse practical uses.

The Effect of Extraction Time of Raja Nangka Banana Peel as Capping Agent on the Characteristic and Antibacterial Activity of ZnO Nanoparticles Against Staphylococcus epidermidis

A green chemistry-based ZnO nanoparticle synthesis method based on plant extracts has been developed. Raja nangka banana peel is one of them. The extraction time is one of the elements that influences the amounts of secondary metabolites. The longer the extraction time, the more secondary metabolites are obtained. If the optimal time is exceeded, the secondary metabolite compounds will decrease. The purpose of this research was to determine the optimal time to extract secondary metabolites from the raja nangka banana peel and to know the effect of extraction time on the characteristics of ZnO nanoparticles, which include morphology, size, and antibacterial activity against Staphylococcus epidermidis. The steps of this research: maceration, phytochemical tests and total levels tests, synthesis of ZnO nanoparticles, characterization, and antibacterial activity test against Staphylococcus epidermidis. Maceration for 24 hours is the best time for extracting secondary metabolites from raja nangka banana peels. The SEM test results show that the morphology of the three samples had agglomeration. The ZnO nanoparticles with 24-hour raja nangka banana peel extract had a smaller size of 295.2 nm and were spherical. Inhibition zone diameter from ZnO nanoparticles with 24-hour raja nangka banana peel extract has a larger area of 5.65 mm.

Effect of La3+ and Ce3+ dopant ions on structural, optical, magnetic, and antibacterial activity of ZnO nanoparticles

In the present study, pure and co-doped zinc oxide (ZnO) nanoparticles (Zn 1−2 x La x Ce x O) with atomic percentages x = 0, 0.5, 1.5, 2.5, and 3.5 at% were synthesized via the chemical co-precipitation method. The impact of lanthanum and cerium dopant ions (La 3+ and Ce 3+ ions, respectively) on the structural, morphological, optical, magnetic, and antibacterial activity of the ZnO nanoparticles was investigated. X-ray diffraction patterns reveal the wurtzite hexagonal crystal structure of ZnO nanoparticles (NPs) with the formation of two secondary phases (CeO 2 and La 2 O 3 ) when x =1.5 and 2.5 at% or higher, respectively. La 3+ and Ce 3+ ions show a high impact on the morphology of ZnO NPs, as revealed by transmission electron microscopy analysis. Fourier transform infrared spectroscopy results indicate that La 3+ and Ce 3+ ions induce a red shift in the zinc–oxygen (Zn–O) vibrational mode. The incorporation of La 3+ and Ce 3+ ions into the ZnO matrix showed a remarkable impact on the ZnO NP optical properties. At room temperature, the M–H magnetic hysteresis of the synthesized samples reveal a combination of both diamagnetic and ferromagnetic contributions. The antibacterial properties of the synthesized NPs were also evaluated against six bacterial strains using the agar well diffusion method. The synthesized NPs suppressed the growth of the investigated bacteria with various degrees of toxicity.

Pomegranate Peel Extract-Mediated Green Synthesis of ZnO-NPs: Extract Concentration-Dependent Structure, Optical, and Antibacterial Activity

Plant-based nanoparticles (NPs) have many advantages over physical and chemical methods and featured with several medicinal and biological applications. In this study, zinc oxide NPs (ZnO-NPs) were synthesized using pomegranate peel aqueous extract, under mild and ecofriendly conditions. The ZnO-NPs structure, morphology, and optical properties were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR), and ultraviolet-visible (UV-Vis). Antibacterial activity against Gram-positive and Gram-negative strains were evaluated using the disk diffusion method. The effect of extract concentration (20, 30, and 40 mL) on the final properties of NPs, as well as the NPs concentration used for antibacterial test (50, 100, and 200 mg/mL), were also studied. The results indicate a hexagonal structure with particle size increases as extract concentration increase (D = 18.53, 29.88, and 30.34 nm), while the optical bandgap was decreased (Eg = 2.87, 2.80, and 1.92 eV). The antibacterial activity of ZnO-NPs indicated high efficiency, similar or even higher than that of the control azithromycin, more against S. aureus, increased with NPs concentration, and preferred when NPs prepared from high extract concentration. Such promising physicochemical properties support the usefulness and efficacy of the reported bio-route for production of ZnO-NPs and may encourage its application for large-scale production.

Fabrication, Characterization, Anticancer and Antibacterial Activities of ZnO Nanoparticles Doped with Y and Ce Elements

Fabrication, Characterization, Anticancer and Antibacterial Activities of ZnO Nanoparticles Doped with Y and Ce Elements

Biosynthesis of ZnO Nanoparticles from Aqueous Extract of Moringa Oleifera L.: Its Application as Antibacterial and Photocatalyst

ZnO nanoparticles were successfully synthesized by the biosynthesis method using water extract of Moringa leaf (Moringa oleifera L.) as a reducing agent and stabilizer as well as a capping agent. This study aimed to characterize ZnO nanoparticles and their application as antibacterial and photocatalyst. Characterization was carried out using Fourier Transform Infrared (FT-IR) Spectroscopy and X-Ray Diffraction (XRD). The biosynthesis ZnO nanoparticles have a hexagonal wurtzite phase with an average crystal size of 16.97 nm and a crystallinity level of 78.49%. Antibacterial activity of ZnO nanoparticles with concentrations of 3%, 6%, 9% resulted in an average inhibition zone of bacterial growth in S. aureus was 19.6 0.16; 21.8 0.33; 24.3 0.14 and in E.coli it is 9.87 0.2; 11.3 0.04; 11.57 0.06. The greater the concentration of ZnO nanoparticles, the larger the diameter of the inhibition zone. The result of photodegradation of methylene blue is greatest with variations in the mass of ZnO nanoparticles and the concentration of methylene blue is 95% with a nanoparticle mass of 120 mg, methylene blue concentration of 10 ppm, and an irradiation time of 150 minutes.

Antibacterial activity of nano zinc oxide green-synthesised from Gardenia thailandica triveng. Leaves against Pseudomonas aeruginosa clinical isolates: in vitro and in vivo study

The increasing emergence of bacterial resistance is a challenge for the research community, thus novel antibacterial agents should be developed. Metal nanoparticles are promising antibacterial agents and could solve the problem of antibiotic resistance. Herein, we used Gardenia thailandica methanol extract (GTME) to biogenically synthesise zinc oxide nanoparticles (ZnO-NPs). The characterisation of ZnO-NPs was performed by UV spectroscopy, FTIR, scanning and transmission electron microscopes, dynamic light scattering, and X-ray diffraction. The antibacterial activity of ZnO-NPs was studied both in vitro and in vivo against Pseudomonas aeruginosa clinical isolates. Its minimum inhibitory concentration values ranged from 2 to 64 µg/mL, and it significantly decreased the membrane integrity and resulted in a significant increase in the inner and outer membrane permeability. Also, the ZnO-NPs treated cells possessed a distorted and deformed shape when examined by scanning electron microscope. The in vivo study (biochemical parameters and histological investigation) was conducted and it revealed a protective effect of ZnO-NPs against the deleterious influences of P. aeruginosa bacteria on lung, liver, and kidney tissues. LC-ESI-MS/MS revealed a phytochemical tentative identification of 57 compounds for the first time. We propose that GTME is a useful source for ZnO-NPs which has a promising antibacterial activity.

Effects of Sulfur Doping and Temperature on the Energy Bandgap of ZnO Nanoparticles and Their Antibacterial Activities

Metal oxide nanoparticles (MO-NPs) are presently an area of intense scientific research, attributable to their wide variety of potential applications in biomedical, optical, and electronic fields. MO-NPs such as zinc oxide nanoparticles (ZnO-NPs) and others have a very high surface-area-to-volume ratio and are excellent catalysts. MO-NPs could also cause unexpected effects in living cells because their sizes are similar to important biological molecules, or parts of them, or because they could pass through barriers that block the passage of larger particles. However, undoped MO-NPs like ZnO-NPs are chemically pure, have a higher optical bandgap energy, exhibit electron–hole recombination, lack visible light absorption, and have poor antibacterial activities. To overcome these drawbacks and further outspread the use of ZnO-NPs in nanomedicine, doping seems to represent a promising solution. In this paper, the effects of temperature and sulfur doping concentration on the bandgap energy of ZnO nanoparticles are investigated. Characterizations of the synthesized ZnO-NPs using zinc acetate dihydrate as a precursor by a sol–gel method were done by using X-ray diffraction, ultraviolet–visible spectroscopy, and Fourier transform infrared spectroscopy. A comparative study was carried out to investigate the antibacterial activity of ZnO nanoparticles prepared at different temperatures and different concentrations of sulfur-doped ZnO nanoparticles against Staphylococcus aureus bacteria. Experimental results showed that the bandgap energy decreased from 3.34 to 3.27 eV and from 3.06 to 2.98 eV with increasing temperature and doping concentration. The antibacterial activity of doped ZnO nanoparticles was also tested and was found to be much better than that of bare ZnO nanoparticles.