Surface Of ZnO NPs Research Articles

Effect of a Zinc Phosphate Shell on the Uptake and Translocation of Foliarly Applied ZnO Nanoparticles in Pepper Plants (Capsicum annuum).

Here, isotopically labeled 68ZnO NPs (ZnO NPs) and 68ZnO NPs with a thin 68Zn3(PO4)2 shell (ZnO_Ph NPs) were foliarly applied (40 μg Zn) to pepper plants (Capsicum annuum) to determine the effect of surface chemistry of ZnO NPs on the Zn uptake and systemic translocation to plant organs over 6 weeks. Despite similar dissolution of both Zn-based NPs after 3 weeks, the Zn3(PO4)2 shell on ZnO_Ph NPs (48 ± 12 nm; -18.1 ± 0.6 mV) enabled a leaf uptake of 2.31 ± 0.34 μg of Zn, which is 2.7 times higher than the 0.86 ± 0.18 μg of Zn observed for ZnO NPs (26 ± 8 nm; 14.6 ± 0.4 mV). Further, ZnO_Ph NPs led to higher Zn mobility and phloem loading, while Zn from ZnO NPs was stored in the epidermal tissues, possibly through cell wall immobilization as a storage strategy. These differences led to higher translocation of Zn from the ZnO_Ph NPs within all plant compartments. ZnO_Ph NPs were also more persistent as NPs in the exposed leaf and in the plant stem over time. As a result, the treatment of ZnO_Ph NPs induced significantly higher Zn transport to the fruit than ZnO NPs. As determined by spICP-TOFMS, Zn in the fruit was not in the NP form. These results suggest that the Zn3(PO4)2 shell on ZnO NPs can help promote the transport of Zn to pepper fruits when foliarly applied. This work provides insight into the role of Zn3(PO4)2 on the surface of ZnO NPs in foliar uptake and in planta biodistribution for improving Zn delivery to edible plant parts and ultimately improving the Zn content in food for human consumption.

Synthesis, Characterization, and Ecotoxicology Assessment of Zinc Oxide Nanoparticles by In Vivo Models

The widespread use of zinc oxide nanoparticles (ZnO NPs) in multiple applications has increased the importance of safety considerations. ZnO NPs were synthesized, characterized, and evaluated for toxicity in Artemia salina and zebrafish (Danio rerio). NPs were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy. The hydrodynamic size and stability of the ZnO NP surface were examined using a Zetasizer. Characterization techniques confirmed the ZnO wurtzite structure with a particle size of 32.2 ± 5.2 nm. Synthesized ZnO NPs were evaluated for acute toxicity in Artemia salina using the Probit and Reed and Muench methods to assess for lethal concentration at 50% (LC50). The LC50 was 86.95 ± 0.21 μg/mL in Artemia salina. Physical malformations were observed after 96 h at 50 μg/mL of exposure. The total protein and cytochrome P450 contents were determined. Further analysis was performed to assess the bioaccumulation capacity of zebrafish (Danio rerio) using ICP-OES. ZnO NP content in adult zebrafish was greater in the gastrointestinal tract than in the other tissues under study. The present analysis of ZnO NPs supports the use of Artemia salina and adult zebrafish as relevant models for assessing toxicity and bioaccumulation while considering absorption quantities.

An efficient method to improve the dispersion and biocompatibility of ZnO nanoparticles

As an important inorganic antibacterial nanomaterial, zinc oxide nanoparticles (ZnO NPs) have been widely used in biomedical fields. However, the poor dispersion and potential toxicity greatly limit its application. Surface modification is an effective method to improve the dispersion and biocompatibility of ZnO NPs. In this work, ε-polylysine (ε-PL) was grafted on the surface of ZnO NPs via the combination of mussel inspired method and “Michael addition” reaction. The results showed that the ε-PL grafted ZnO (ZnO@ε-PL) could disperse stably in water more than 72 h, demonstrating ε-PL greatly improves the dispersion of ZnO NPs. Furthermore, the cells viability of ZnO@ε-PL at high concentrations (500 μg/mL) was 143.05 ± 12.63%, indicating that the biocompatibility of ZnO@ε-PL is much better than that of ZnO NPs. This study proposed a feasible and effective strategy to improve the dispersion and biocompatibility of ZnO NPs, which may expand the application of ZnO NPs in the biological field.

Bio‐fabricated ZnO Nanoparticles for Enhanced Photocatalytic Degradation of Methylene Blue and in vitro Antibacterial Activity

AbstractNovel bio‐fabricated ZnO nanoparticles were made from the solution of zinc nitrate in the presence of bio‐components of Jasminum grandiflorum L. The bio‐fabricated ZnO nanoparticles, represented as Jg‐ZnO NPs, were suitably characterized by several state‐of‐the‐art tools. The UV‐Vis absorption band at λmax=370 nm and the characteristic XRD peaks at appropriate positions suggest the formation of ZnO NPs. The XRD pattern revealed the formation of highly crystalline, hexagonal phase and impurity free Jg‐ZnO NPs. The presence of biomolecules on the surface of ZnO NPs was confirmed by FTIR spectral analysis. These NPs have hexagonal structures and flake‐like morphology as revealed by their TEM and SEM analysis, respectively. Further, the Jg‐ZnO NPs exhibit excellent photocatalytic activity against the MB dye under sunlight with a dye degradation efficiency of 99.8 %. Besides, the Jg‐ZnO NPs were also remarkably effective in inhibiting the growth of gram‐positive (S. aureus) as well as gram‐negative (P. aeruginosa and K. pneumoniae) pathogenic bacteria.

Enhanced antibacterial and anticancer activities of plant extract mediated green synthesized zinc oxide-silver nanoparticles.

This study presents a green synthesis approach for the fabrication of zinc oxide-silver nanoparticles (ZnO-Ag-NPs) using Punica granatum fruit peels extract as a natural reducing and stabilizing agent. This eco-friendly method offers a sustainable alternative to conventional methods that often employ toxic or hazardous chemicals. Antibacterial and anti-cancer activities of the green synthesized nanoparticles were then assessed in vitro. X-ray diffraction confirmed the production of ZnO-Ag-NPs with increasing crystallinity in higher pH values. The ZnO-Ag-NPs were found to be agglomerated with spherical Ag-NPs. Fourier Transform Infrared (FTIR) spectra revealed a broad band in ZnO-Ag-NPs ranging from 400-1 to 530 cm-1 with reduced intensity as compared to ZnO-NPs, indicating the formation of Ag-NPs on the surface of ZnO-NPs. The synthesized ZnO-Ag-NPs exhibited potent antibacterial activity against a broad spectrum of bacterial strains, particularly Gram-positive bacteria, with superior inhibition activity compared to ZnO-NPs. Moreover, ZnO-Ag-NPs showed a dose-dependent anti-proliferative effect on colorectal-, lung-, and cervical cancer cells. ZnO-Ag-NPs showed significantly greater efficacy in inhibiting cancer cell growth at a lower concentration of 31.25 μg/mL, compared to ZnO-NPs which required over 500 μg/mL, possibly due to the presence of silver nanoparticles (Ag-NPs). The results obtained from this study demonstrate the potential of green synthesis approaches in the fabrication of therapeutic nanomaterials for cancer treatment, as well as other biomedical applications.

Dual Light Temporal Coding Modes Enabled by Nanoparticle-Mediated Phototransistors via Gate Bias Modulation for Brain-Inspired Visual Perception.

The core integration and cooperation of the retina, neurons, and synapses in the visual systems enable humans to effectively sense and process visual information with low power consumption. To mimic the human visual system, an artificial sensory nerve, along with optical sensing─a paired-pulse ratio (PPR) of the light pulse stimulated currents─and neural coding has been developed. For performing the artificial visual perception functions, we consistently reveal the positive and negative correlations between the PPR index and light pulse time interval by applying two consecutive light stimuli with gate voltages of -10 and 5 V, respectively, to a phototransistor. This phototransistor contains a heterostructured channel layer composed of zinc-oxide nanoparticles (ZnO NPs) interconnected with a solution-processed zinc-tin oxide (ZTO) film. The oxygen adsorption and desorption on the ZnO NP surface under light illumination are responsible for the positive-sloped PPR; the electron trapping effect at the ZnO NP/SiO2 interface is attributed to the negative-sloped PPR. The various accountable light power densities and number of surface trap states are considered to be directly realizing these spike-timing interval-dependent characteristics. The actual benefit of these characteristics is the dual temporal coding modes based on multiplicative operation using a ZTO/ZnO NP phototransistor realized via the active gate voltage modulation. The contrary tendency of the PPR index and temporal coding─a major biological neural coding─is well demonstrated by the potential of ZTO/ZnO NP phototransistors to be implemented in sensor networks for an artificial visual perception.

Rubus ellipticus Sm. Fruit Extract Mediated Zinc Oxide Nanoparticles: A Green Approach for Dye Degradation and Biomedical Applications.

Rubus ellipticus fruits aqueous extract derived ZnO-nanoparticles (NPs) were synthesized through a green synthesis method. The structural, optical, and morphological properties of ZnO-NPs were investigated using XRD, FTIR, UV-vis spectrophotometer, XPS, FESEM, and TEM. The Rietveld refinement confirmed the phase purity of ZnO-NPs with hexagonal wurtzite crystalline structure and p-63-mc space group with an average crystallite size of 20 nm. XPS revealed the presence of an oxygen chemisorbed species on the surface of ZnO-NPs. In addition, the nanoparticles exhibited significant in vitro antioxidant activity due to the attachment of the hydroxyl group of the phenols on the surface of the nanoparticles. Among all microbial strains, nanoparticles’ maximum antibacterial and antifungal activity in terms of MIC was observed against Bacillus subtilis (31.2 µg/mL) and Rosellinia necatrix (15.62 µg/mL), respectively. The anticancer activity revealed 52.41% of A549 cells death (IC50: 158.1 ± 1.14 µg/mL) at 200 μg/mL concentration of nanoparticles, whereas photocatalytic activity showed about 17.5% degradation of the methylene blue within 60 min, with a final dye degradation efficiency of 72.7%. All these results suggest the medicinal potential of the synthesized ZnO-NPs and therefore can be recommended for use in wastewater treatment and medicinal purposes by pharmacological industries.

Synthesis, characterization, and photocatalytic application of silver doped zinc oxide nanoparticles

The advancement in nanotechnology has influenced the improvement in the photocatalytic performance of zinc oxide nanoparticles (ZnO NPs). The photocatalytic activities of ZnO are within irradiation wavelengths in the ultraviolet region and this hinders its efficiency in photocatalytic applications. Undoped and silver doped ZnO nanoparticles (Ag-doped ZnO NPs) were successfully prepared by co-precipitation technique at Ag doping concentrations of 0, 0.25, 0.5, 0.75, and 1 % to enhance the photocatalytic ability of ZnO NPs. The XRD results indicate a hexagonal wurtzite structure of the undoped and Ag-doped ZnO NPs with the estimated crystalline size ranges from 30.79, 23.72, 36.97, 21.49, and 25.66 nm, respectively, for ZnO at Ag doping concentrations. The SEM micrograph revealed the uniform distribution of Ag on the surface of ZnO NPs and a decrease in the size of the particle as concentration increases. The displacement in the absorption edge of ZnO to a higher wavelength led to narrowing the optical bandgap of ZnO due to Ag doping, as observed in the DRS spectra. Photocatalytic performance and photodegradation experiments were conducted using a model methylene blue (MB) dye contaminated in water. The dye concentration decreases as irradiation time increases in the presence of the photocatalyst with the improved performance of less exposure time and the highest dye degradation of about 98 %. It was revealed that the photocatalytic activity of ZnO toward MB degradation was effectively improved by Ag doping. Therefore, Ag doping of ZnO NPs had the synergetic effect of enhancing the photocatalytic activity of ZnO NPs.

Tailoring of Novel Azithromycin-Loaded Zinc Oxide Nanoparticles for Wound Healing.

Skin is the largest mechanical barrier against invading pathogens. Following skin injury, the healing process immediately starts to regenerate the damaged tissues and to avoid complications that usually include colonization by pathogenic bacteria, leading to fever and sepsis, which further impairs and complicates the healing process. So, there is an urgent need to develop a novel pharmaceutical material that promotes the healing of infected wounds. The present work aimed to prepare and evaluate the efficacy of novel azithromycin-loaded zinc oxide nanoparticles (AZM-ZnONPs) in the treatment of infected wounds. The Box–Behnken design and response surface methodology were used to evaluate loading efficiency and release characteristics of the prepared NPs. The minimum inhibitory concentration (MIC) of the formulations was determined against Staphylococcus aureus and Escherichia coli. Moreover, the anti-bacterial and wound-healing activities of the AZM-loaded ZnONPs impregnated into hydroxyl propyl methylcellulose (HPMC) gel were evaluated in an excisional wound model in rats. The prepared ZnONPs were loaded with AZM by adsorption. The prepared ZnONPs were fully characterized by XRD, EDAX, SEM, TEM, and FT-IR analysis. Particle size distribution for the prepared ZnO and AZM-ZnONPs were determined and found to be 34 and 39 nm, respectively. The mechanism by which AZM adsorbed on the surface of ZnONPs was the best fit by the Freundlich model with a maximum load capacity of 160.4 mg/g. Anti-microbial studies showed that AZM-ZnONPs were more effective than other controls. Using an experimental infection model in rats, AZM-ZnONPs impregnated into HPMC gel enhanced bacterial clearance and epidermal regeneration, and stimulated tissue formation. In conclusion, AZM -loaded ZnONPs are a promising platform for effective and rapid healing of infected wounds.

A new stratagem for the synthesis of novel ZnO-Insulin nanoparticles for controlled release of glucose in blood

In this novel research, ZnO–insulin nanoparticles were prepared as glucose level regulator in the blood by sol-gel route adopting micelle template approach. The physicochemical features of the novel nanoparticles were investigated by XRD, FTIR, EDX and HRTEM which reveal noted crystallinity distortion when insulin is present. ZnONPs slight crystallite distortion could aid formulating ZnONPs activity biomedically in presence of protein entities. A homogeneous dispersion of insulin on the surface of ZnONPs was detected by HRTEM could also indicate favorable attachment mutual sites between the ZnO surface and the structural amino acid groups. The hypoglycemic activity effect of ZnONPs, ZnONPs-Insulin (1:1) and ZnONPs-Insulin (1:0.5) drugs was proven and compared to that of insulin in this study. The data showed that ZnONPs-Insulin (1:1) drug was the most potent hypoglycemic agent of them.

Green Fabrication of Zinc Oxide Nanoparticles Using Phlomis Leaf Extract: Characterization and In Vitro Evaluation of Cytotoxicity and Antibacterial Properties.

Green nanoparticle synthesis is an environmentally friendly approach that uses natural solvents. It is preferred over chemical and physical techniques due to the time and energy savings. This study aimed to synthesize zinc oxide nanoparticles (ZnO NPs) through a green method that used Phlomis leaf extract as an effective reducing agent. The synthesis and characterization of ZnO NPs were confirmed by UV-Vis spectrophotometry, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Dynamic light scattering (DLS), Zeta potential, and Field Emission Scanning Electron Microscope (FESEM) techniques. In vitro cytotoxicity was determined in L929 normal fibroblast cells using MTT assay. The antibacterial activity of ZnO nanoparticles was investigated using a disk-diffusion method against S. aureus and E. coli, as well as minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) content concentrations. XRD results confirmed the nanoparticles’ crystalline structure. Nanoparticle sizes were found to be around 79 nm by FESEM, whereas the hydrodynamic radius of nanoparticles was estimated to be around 165 ± 3 nm by DLS. FTIR spectra revealed the formation of ZnO bonding and surfactant molecule adsorption on the surface of ZnO NPs. It is interesting to observe that aqueous extracts of Phlomis leave plant are efficient reducing agents for green synthesis of ZnO NPs in vitro, with no cytotoxic effect on L929 normal cells and a significant impact on the bacteria tested.

Green Synthesis, Characterization of Zinc Oxide Nanoparticles, and Examination of Properties for Dye-Sensitive Solar Cells Using Various Vegetable Extracts

The production of zinc oxide nanoparticles (ZnO NPs) utilizing different vegetable extracts (onion, cabbage, carrot, and tomato) was performed in this research owing to its excellency over other methods of synthesis, namely, simplicity, environmental friendliness, and the elimination of harmful compounds. Fresh extracted onion, cabbage, carrot, and tomato of ZnO NPs are characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-visible spectroscopy. FTIR findings demonstrate that the prepared nanoparticles were observed in the spectrum of 626 cm-1–1219 cm-1 with some other functional groups. Wurtzite hexagonal structure of the prepared ZnO NPs was observed from XRD results. In addition, the prepared nanoparticles were failed into nanoscales (17 nm, 18 nm, 24 nm, and 15 nm) calculated from Scherrer’s equation. Nearly spherical shapes were seen from SEM image for onion and tomato extraction while rod and tube for carrot and cabbage, respectively. Two broad peaks were observed from UV-vis spectroscopy results for each extract. The presence of a wide range of energy bandgaps in the region of 3-4 eV was detected, indicating that ZnO NP material can be employed in metal oxide semiconductor-based systems. The dye-sensitive solar cell based on ZnO NPs has been successfully synthesized, and the efficiency of the device has been evaluated by measuring the current density-voltage behaviour under the presence of artificial sunshine. The increased effectiveness of the manufactured dye-sensitive solar cell is attributable to a large improvement in dye molecular adsorption onto the surface of ZnO NPs. Thus, the usage of the green produced ZnO NPs with creating dye sensitivity solar cell is a simple and viable way for the well-being of our future.

The Study on Molecular Profile Changes of Pathogens via Zinc Nanocomposites Immobilization Approach.

The most critical group of all includes multidrug resistant bacteria that pose a particular threat in hospitals, as they can cause severe and often deadly infections. Modern medicine still faces the difficult task of developing new agents for the effective control of bacterial-based diseases. The targeted administration of nanoparticles can enhance the efficiency of conventional pharmaceutical agents. However, the interpretation of interfaces’ interactions between nanoparticles and biological systems still remains a challenge for researchers. In fact, the current research presents a strategy for using ZnO NPs immobilization with ampicillin and tetracycline. Firstly, the study provides the mechanism of the ampicillin and tetracycline binding on the surface of ZnO NPs. Secondly, it examines the effect of non-immobilized ZnO NPs, immobilized with ampicillin (ZnONPs/AMP) and tetracycline (ZnONPs/TET), on the cells’ metabolism and morphology, based on the protein and lipid profiles. A sorption kinetics study showed that the antibiotics binding on the surface of ZnONPs depend on their structure. The efficiency of the process was definitely higher in the case of ampicillin. In addition, flow cytometry results showed that immobilized nanoparticles present a different mechanism of action. Moreover, according to the MALDI approach, the antibacterial activity mechanism of the investigated ZnO complexes is mainly based on the destruction of cell membrane integrity by lipids and proteins, which is necessary for proper cell function. Additionally, it was noticed that some of the identified changes indicate the activation of defense mechanisms by cells, leading to a decrease in the permeability of a cell’s external barriers or the synthesis of repair proteins.

Synthesis of ZnO nanoparticles using peels of Passiflora foetida and study of its activity as an efficient catalyst for the degradation of hazardous organic dye

Creating a sustainable and effective approach to handling organic contaminants from industrial waste is an ongoing problem. In the present study, ZnO nanoparticles (ZnO NPs) were synthesized under a controlled ultrasound cavitation technique using the extract of Passiflora foetida fruit peels, which act as a reducing (i.e., reduction of metal salt) and stabilizing agent. The formation of monodispersed and hexagonal morphology (average size approximately 58 nm with BET surface area 30.83m2/g). The synthesized ZnO NPs were characterized by a various technique such as UV–visible spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Dynamic light scattering (DLS). Further, the XRD pattern confirmed the hexagonal wurtzite structure of synthesized ZnONPs. The ZnO NPs exhibit excellent degradation efficiency towards organic pollutant dyes, i.e., Methylene blue (MB) (93.25% removal) and Rhodamine B (91.06% removal) in 70 min, under natural sunlight with apparent rate constant 0.0337 min−1 (R2 = 0.9749) and 0.0347 min−1 (R2 = 0.9026) respectively.Zeta potential study shows the presence of a negative charge on the surface of ZnO NPs. The use of green synthesized ZnO NPs is a good choice for wastewater treatment, given their high reusability and photocatalytic efficiency, along with adaptability to green synthesis.

Investigation of Functionalized Surface Charges of Thermoplastic Starch/Zinc Oxide Nanocomposite Films Using Polyaniline: The Potential of Improved Antibacterial Properties.

Improving the antibacterial activity of biodegradable materials is crucial for combatting widespread drug-resistant bacteria and plastic pollutants. In this work, we studied polyaniline (PANI)-functionalized zinc oxide nanoparticles (ZnO NPs) to improve surface charges. A PANI-functionalized ZnO NP surface was prepared using a simple impregnation technique. The PANI functionalization of ZnO successfully increased the positive surface charge of the ZnO NPs. In addition, PANI-functionalized ZnO improved mechanical properties and thermal stability. Besides those properties, the water permeability of the bionanocomposite films was decreased due to their increased hydrophobicity. PANI-functionalized ZnO NPs were applied to thermoplastic starch (TPS) films for physical properties and antibacterial studies using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The PANI-functionalized ZnO bionanocomposite films exhibited excellent antibacterial activity for both E. coli (76%) and S. aureus (72%). This result suggests that PANI-functionalized ZnO NPs can improve the antibacterial activity of TPS-based bionanocomposite films.

Roles of pH, cation valence, and ionic strength in the stability and aggregation behavior of zinc oxide nanoparticles

The effects of pH, cation valence, and ionic strength (IS) on the stability and aggregation behavior of zinc oxide nanoparticles (ZnO NPs) were investigated in this study. Results showed that ZnO NPs were most prone to aggregation at the isoelectric point (pH = 8.7), with an aggregation rate (ΔD/Δt) of 30.1. ZnO NPs showed a greater propensity for dissolution at lower pH (pH < 7), and Zn2+ was more rapidly released into the aqueous phase in acidic solutions than neutral or alkaline conditions. The C/C0 of ZnO NPs was about 21.56% and remained stable in acidic solution of pH 4.0. Additionally, slow sedimentation with a C/C0 ratio of 95.0% was observed due to an increase in repulsive interactions between nanoparticles under pH = 10. The effect of cations on the ΔD/Δt of ZnO NPs decreased in strength as follows: Ca2+ > Mg2+ > K+ > Na+. High-valence metal cations (Ca2+, Mg2+) were more competitively adsorbed onto the surface of ZnO NPs with a hydrogen atom due to Coulomb's law, increasing the zeta potential and stabilizing the suspension of ZnO NPs at IS < 10 mM. Furthermore, compression of the electric double layer (EDL) became stronger than electrostatic adsorption with increasing IS, reaching a maximum ΔD/Δt of 23.3 (Ca2+, pH = 7, IS = 1 M). The C/C0 ratio of ZnO NPs decreased from 100% to 56.5% (Na+), 52.2% (K+), 45.2% (Mg2+), and 40.1% (Ca2+) at pH = 7 and an IS of 0.5 M. In addition to the cation valence, the hydration forces and ionic radii of the metal cations might be other factors that affected the interactions of metal cations with ZnO NPs. Finally, the total interaction energy between ZnO NPs was calculated using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theoretical formula, and the calculated results were in agreement with the experimental outcomes under various aquatic environmental conditions.

Characterization and Photoactivity of Cotton Loaded with ZnO NPs

In this work, ZnO NPs were prepared by a simple co-precipitation technique. Cotton fibers loaded with ZnO NPs were prepared also. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis spectrophotometer have been used to characterize the prepared samples. The photocatalytic properties of the cotton loaded with ZnO (C-ZnO) and ZnO NPs, were studied under sunlight irradiation and lamp illumination as a function on time. The results showed that X-ray diffraction of ZnO NPs has a single-phase wurtzite structure with an average particle size of 29 nm. The morphology on the surface of ZnO NPs has a spherical shape. The optical band gap of ZnO nanoparticles was 3.37 eV. The photocatalytic confirms that C-ZnO exhibited higher photocatalytic activities than ZnO NPs.

Microscopic and spectroscopic study of the corona formation and unfolding of human haemoglobin in presence of ZnO nanoparticles.

The interaction of zinc oxide nanoparticles (ZnO NPs) with human haemoglobin (Hb) is studied for the biologically safe application of ZnO NPs in the human body. The Hb corona is formed around the ZnO nanoparticles, directly observed from high-resolution transmission electron microscopy (HRTEM) images. Hb formed 'hard corona' on the surface of ZnO NPs from an exponential association mechanism over a very short duration, as well as unfolding of Hb that occurred over a long lifetime. Dynamic light scattering measurements demonstrated that the ZnO NPs were completely covered by Hb with shell thickness of c. 6nm that formed a 'hard corona'. Zeta potential measurements represented that the ZnO NPs were fully covered by Hb molecules using an exponential association mechanism. Tryptophans (TRY), as well as heme-porphyrin moieties of Hb, are the major binding sites for ZnO NPs. The nature of the interaction between ZnO NPs and Hb was analysed from the fluorescence quenching of TRYs. Electrostatic interaction, along with the hydrophobic interaction between ZnO NPs and Hb, is responsible for the conformational change in Hb due to increase in the percentage of β-sheets together with a decrease in α-helices.

Synthesis, physico-chemical characterization, antimicrobial activity and toxicological features of Ag[sbnd]ZnO nanoparticles

Silver-zinc oxide nanoparticles (AgZnO NPs) were chemically synthesized by the deposition of Ag NPs on the surface of ZnO NPs using silver nitrate, three types of anionic polyelectrolytes and citric acid as reagents. The Wavelength Dispersive X-ray Fluorescence (WDXRF) spectrometry of AgZnO NPs revealed 0.41–0.69 wt% Ag, and balance ZnO. The existence of Ag NPs on the surface of ZnO NPs with hexagonal wurtzite structure was highlighted by X-ray Diffraction (XRD) analysis, scanning electron microscopy (SEM), and Ultraviolet–Visible (UV–Vis) spectroscopy. The diffuse reflectance absorption of AgZnO NPs in the visible light region increased with the increase of Ag NPs content. The Fourier Transform Infrared (FTIR) spectrometry revealed no chemical bonding between Ag NPs and ZnO NPs and confirmed the presence of functional groups characteristic to ZnO and carboxylic acid salts. The newly synthesized AgZnO NPs displayed antimicrobial activity against all the tested medically relevant pathogens, with minimal (biofilm) inhibitory concentrations ranging from 1.875 mg/mL to 7.5 mg/mL. Although the in vitro genotoxicity assay revealed a relatively high micronuclei index, the in vivo micronucleus (MN) test revealed a low MN frequency in animals treated with AgZnO NPs. The histopathological analysis revealed non-significant structural changes of the hepatic parenchyma, renal cortex and intestinal mucosa and minimal inflammatory reactions. The AgZnO NPs administration induced TUNEL positive nuclei of Kupffer cells in the liver parenchyma. The present study shows that the newly synthesized AgZnO NPs are active against planktonic and adherent microorganisms and could be exploited to develop novel antimicrobial strategies for the biotechnology and biomedical fields. Easy scalability of the developed chemical synthesis is a major advantage in producing large batches of AgZnO NPs with reproducible properties.

Enhanced engineered ZnO nanostructures and their antibacterial activity against urinary, gastrointestinal, respiratory and dermal genital infections

Antimicrobial effect of nano-metal oxides especially ZnO NPs and their potent nanofluids against microorganisms have been studied in vitro conditions for years. Here, three kinds of gram-negative and eight gram-positive bacteria were applied investigating minimum inhibitory concentration, minimum bactericidal concentration and well-diffusion method of ZnO nanofluids against these pathogens. Gentamycin and nalidixic acid were then used as strong references in inhibition zone results. In this study, four different formulations of ZnO nanofluids containing various ZnO NPs (as basic scaffold framework) along with several effective chemical reagents in nanofluids were fabricated, whereas the best matched nanoformulation was very promising against Streptococcus pyogenes, Enterococcus faecalis and Escherichia coli. In such nanoformulation, the surface of ZnO NPs was functionalized or engineered with CNT-amine, and then formulated with ecofriendly ZnO nanopolymer (ZnO/PVP). The formulated ZnO/PVP could perform as a synergism co-assistant in final energetic nanofluid throughout the antibacterial activity tests. Final nanofluid was successfully contacted with interface of different bacteria cell membrane such as nosocomial, skin, urinary and bronchial in comparison with the controls. This new biofilm could create potential antimicrobial agents when ZnO nanofluid surround the bacteria and produce a new complex–matrix structure. Such event further disturbs reactive oxygen conductivity and effectively suppressed bacteria viability leading eventually to necrotic cell death. The high resistance in this long bioprocess system, provided special strong surface energy and powerful effectiveness of ZnO NPs in granting antimicrobial coating properties that make this formulation a new research opportunity for various industries addressing medical tissue engineering.