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Construction of Zinc Oxide into Different Morphological Structures to Be Utilized as Antimicrobial Agent against Multidrug Resistant Bacteria.

Elkady MF, Shokry Hassan H, Hafez EE, Fouad A - Bioinorg Chem Appl (2015)

Bottom Line: Nano-ZnO has been successfully implemented in particles, rods, and tubes nanostructures via sol-gel and hydrothermal techniques.The activity of produced nano-ZnO was determined by disc diffusion technique and the results revealed that ZnO nanotubes recorded high activity against the studied strains due to their high surface area equivalent to 17.8 m(2)/g.Although the annealing process of ZnO improves the degree of material crystallinity, however, it declines its surface area and consequently its antimicrobial activity.

View Article: PubMed Central - PubMed

Affiliation: Fabrication Technology Department, Advanced Technology and New Materials Research Institute (ATNMRI), City of Scientific Research and Technological Applications, Alexandria 21934, Egypt ; Chemical and Petrochemical Engineering Department, Egypt-Japan University of Science and Technology, New Borg El-Arab City, Alexandria 21934, Egypt.

ABSTRACT
Nano-ZnO has been successfully implemented in particles, rods, and tubes nanostructures via sol-gel and hydrothermal techniques. The variation of the different preparation parameters such as reaction temperature, time, and stabilizer agents was optimized to attain different morphological structures. The influence of the microwave annealing process on ZnO crystallinity, surface area, and morphological structure was monitored using XRD, BET, and SEM techniques, respectively. The antimicrobial activity of zinc oxide produced in nanotubes structure was examined against four different multidrug resistant bacteria: Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) strains. The activity of produced nano-ZnO was determined by disc diffusion technique and the results revealed that ZnO nanotubes recorded high activity against the studied strains due to their high surface area equivalent to 17.8 m(2)/g. The minimum inhibitory concentration (MIC) of ZnO nanotubes showed that the low concentrations of ZnO nanotubes could be a substitution for the commercial antibiotics when approached in suitable formula. Although the annealing process of ZnO improves the degree of material crystallinity, however, it declines its surface area and consequently its antimicrobial activity.

No MeSH data available.


Related in: MedlinePlus

SEM micrographs of ZnO prepared using sol-gel technique with different surfactant agents: (a) PVP, (b) PVA, (c) CTAB, (d) TEA, and (e) PEG.
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fig3: SEM micrographs of ZnO prepared using sol-gel technique with different surfactant agents: (a) PVP, (b) PVA, (c) CTAB, (d) TEA, and (e) PEG.

Mentions: (ii) Morphological Structure (SEM).Figure 3 investigated the morphological structures of the different prepared ZnO in the presence of different surfactants. The formation of different nanorods and nanoparticles that possess well-defined hexagonal faces was indicated for the different studied surfactants. In case of using PVP and PVA as surfactants, a large quantity of straight rods and a small amount of irregular ones are formed. It was observed that the aspect ratio (the average length-to-diameter ratio) of formed nanorods decreased from 9 to 4 with the surfactant change from PVP to PVA. The suggested mechanism for nanorods ZnO formation in the presence of either PVP or PVA may be considered due to the decomposition of Zn(OH)2 within 60 minutes' heating that formed ZnO nucleation. The remaining reaction time may be considered as the time of nuclei growth in other directions that resulted from dissolution and reprecipitation of the existing ZnO particles that formed the nanorods structures. On the other hand, it was evident from Figure 3 that ZnO formed in nanoparticles structure with lower diameters ranged from 30 to 50 nm in the presence of CTAB, TEA, and PEG as surfactants. Accordingly, all the reaction time for ZnO formation in case of utilizing CTAB, TEA, and PEG as surfactants may be spent for decomposition of Zn(OH)2 to form ZnO nucleation that was promoted into crystalline structures of nanoparticles at the same nucleation direction. So, it is concluded that the surfactant type affects the size and morphology of ZnO formed according to the nucleation and growth mechanisms [26]. It is indispensable to understand the growth mechanism in order to control and design tailored structures. In the ZnO and surfactant system, the chemical adsorption is basically assigned to the coordination between the surfactant and Zn2+ ions or ZnO. Generally, surfactants were used as capping agent because there is a strong interaction between the surfaces of nanocrystals and surfactant based on the strong coordination ability of O and N atoms in the surfactant. It is believed that the selective adsorption of surfactants on various crystallographic planes of the nanocrystals played a vital role in controlling the morphology of the products [27]. Based on the degree of adsorption, the electrostatic force of attraction, and interaction between the surfactant molecules and Zn2+ ionic group, a particular morphology with specific orientation is synthesized [28], where the surfactant in aqueous solution formed a microreactor through various interactions. When reactants were added, the precursors of ZnO nucleated in this reactor [29]. Subsequently, the reactor could significantly prevent the growth of some special crystalline faces and also preferentially promoted other crystalline faces' growth (Figure 4).


Construction of Zinc Oxide into Different Morphological Structures to Be Utilized as Antimicrobial Agent against Multidrug Resistant Bacteria.

Elkady MF, Shokry Hassan H, Hafez EE, Fouad A - Bioinorg Chem Appl (2015)

SEM micrographs of ZnO prepared using sol-gel technique with different surfactant agents: (a) PVP, (b) PVA, (c) CTAB, (d) TEA, and (e) PEG.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4588359&req=5

fig3: SEM micrographs of ZnO prepared using sol-gel technique with different surfactant agents: (a) PVP, (b) PVA, (c) CTAB, (d) TEA, and (e) PEG.
Mentions: (ii) Morphological Structure (SEM).Figure 3 investigated the morphological structures of the different prepared ZnO in the presence of different surfactants. The formation of different nanorods and nanoparticles that possess well-defined hexagonal faces was indicated for the different studied surfactants. In case of using PVP and PVA as surfactants, a large quantity of straight rods and a small amount of irregular ones are formed. It was observed that the aspect ratio (the average length-to-diameter ratio) of formed nanorods decreased from 9 to 4 with the surfactant change from PVP to PVA. The suggested mechanism for nanorods ZnO formation in the presence of either PVP or PVA may be considered due to the decomposition of Zn(OH)2 within 60 minutes' heating that formed ZnO nucleation. The remaining reaction time may be considered as the time of nuclei growth in other directions that resulted from dissolution and reprecipitation of the existing ZnO particles that formed the nanorods structures. On the other hand, it was evident from Figure 3 that ZnO formed in nanoparticles structure with lower diameters ranged from 30 to 50 nm in the presence of CTAB, TEA, and PEG as surfactants. Accordingly, all the reaction time for ZnO formation in case of utilizing CTAB, TEA, and PEG as surfactants may be spent for decomposition of Zn(OH)2 to form ZnO nucleation that was promoted into crystalline structures of nanoparticles at the same nucleation direction. So, it is concluded that the surfactant type affects the size and morphology of ZnO formed according to the nucleation and growth mechanisms [26]. It is indispensable to understand the growth mechanism in order to control and design tailored structures. In the ZnO and surfactant system, the chemical adsorption is basically assigned to the coordination between the surfactant and Zn2+ ions or ZnO. Generally, surfactants were used as capping agent because there is a strong interaction between the surfaces of nanocrystals and surfactant based on the strong coordination ability of O and N atoms in the surfactant. It is believed that the selective adsorption of surfactants on various crystallographic planes of the nanocrystals played a vital role in controlling the morphology of the products [27]. Based on the degree of adsorption, the electrostatic force of attraction, and interaction between the surfactant molecules and Zn2+ ionic group, a particular morphology with specific orientation is synthesized [28], where the surfactant in aqueous solution formed a microreactor through various interactions. When reactants were added, the precursors of ZnO nucleated in this reactor [29]. Subsequently, the reactor could significantly prevent the growth of some special crystalline faces and also preferentially promoted other crystalline faces' growth (Figure 4).

Bottom Line: Nano-ZnO has been successfully implemented in particles, rods, and tubes nanostructures via sol-gel and hydrothermal techniques.The activity of produced nano-ZnO was determined by disc diffusion technique and the results revealed that ZnO nanotubes recorded high activity against the studied strains due to their high surface area equivalent to 17.8 m(2)/g.Although the annealing process of ZnO improves the degree of material crystallinity, however, it declines its surface area and consequently its antimicrobial activity.

View Article: PubMed Central - PubMed

Affiliation: Fabrication Technology Department, Advanced Technology and New Materials Research Institute (ATNMRI), City of Scientific Research and Technological Applications, Alexandria 21934, Egypt ; Chemical and Petrochemical Engineering Department, Egypt-Japan University of Science and Technology, New Borg El-Arab City, Alexandria 21934, Egypt.

ABSTRACT
Nano-ZnO has been successfully implemented in particles, rods, and tubes nanostructures via sol-gel and hydrothermal techniques. The variation of the different preparation parameters such as reaction temperature, time, and stabilizer agents was optimized to attain different morphological structures. The influence of the microwave annealing process on ZnO crystallinity, surface area, and morphological structure was monitored using XRD, BET, and SEM techniques, respectively. The antimicrobial activity of zinc oxide produced in nanotubes structure was examined against four different multidrug resistant bacteria: Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) strains. The activity of produced nano-ZnO was determined by disc diffusion technique and the results revealed that ZnO nanotubes recorded high activity against the studied strains due to their high surface area equivalent to 17.8 m(2)/g. The minimum inhibitory concentration (MIC) of ZnO nanotubes showed that the low concentrations of ZnO nanotubes could be a substitution for the commercial antibiotics when approached in suitable formula. Although the annealing process of ZnO improves the degree of material crystallinity, however, it declines its surface area and consequently its antimicrobial activity.

No MeSH data available.


Related in: MedlinePlus