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1.
Bioprocess Biosyst Eng ; 44(4): 875-889, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33527232

RESUMO

Aqueous leaf extract of Ziziphus mauritiana Lam. was successfully used to synthesize zinc oxide (ZnO) and magnesium-doped ZnO (Mg-doped ZnO) particles and acted as capping and stabilizing agent. UV-Vis diffuse reflectance spectra showed that optical band gap energy of ZnO has narrowed from 3.11 to 3.08 eV and 3.03 eV when doped with 1% Mg and 5% Mg, respectively. Powder X-ray diffraction and X-ray photoelectron spectroscopy studies confirmed the purity and crystalline nature of the synthesized materials. FT-IR spectroscopy revealed the presence of phytochemicals coated on the surface of synthesized materials. The synthesized materials were found to effectively scavenge DPPH radicals in the presence of visible light in comparison to the dark. The antibacterial properties of the synthesized materials were evaluated against Staphylococcus aureus and Escherichia coli. The obtained results revealed that Staphylococcus aureus seemed to be more sensitive to the green synthesized ZnO and Mg-doped ZnO than Escherichia coli.


Assuntos
Antibacterianos/química , Antioxidantes/química , Magnésio/química , Extratos Vegetais/análise , Folhas de Planta/metabolismo , Óxido de Zinco/química , Ziziphus/metabolismo , Ácido Ascórbico/química , Escherichia coli/metabolismo , Química Verde , Microscopia Eletrônica de Varredura , Compostos Fitoquímicos , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/metabolismo , Difração de Raios X
2.
Molecules ; 26(9)2021 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-33922577

RESUMO

The possibility of using silver nanoparticles (AgNPs) to enhance the plants growth, crop production, and control of plant diseases is currently being researched. One of the most effective approaches for the production of AgNPs is green synthesis. Herein, we report a green and phytogenic synthesis of AgNPs by using aqueous extract of strawberry waste (solid waste after fruit juice extraction) as a novel bioresource, which is a non-hazardous and inexpensive that can act as a reducing, capping, and stabilizing agent. Successful biosynthesis of AgNPs was monitored by UV-visible spectroscopy showing a surface plasmon resonance (SPR) peak at ~415 nm. The X-ray diffraction studies confirm the face-centered cubic crystalline AgNPs. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques confirm the rectangular shape with an average size of ~55 nm. The antibacterial and antifungal efficacy and inhibitory impact of the biosynthesized AgNPs were tested against nematode, Meloidogyne incognita, plant pathogenic bacterium, Ralstonia solanacearum and fungus, Fusarium oxysporum. These results confirm that biosynthesized AgNPs can significantly control these plant pathogens.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Fusarium/efeitos dos fármacos , Nanopartículas Metálicas/química , Ralstonia solanacearum/efeitos dos fármacos , Prata/química
3.
Nanomedicine ; 20: 102016, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31158499

RESUMO

Nanoengineering the topology of titanium (Ti) implants has the potential to enhance cytocompability and biocompatibility properties as implant surfaces play a decisive role in determining clinical success. Despite developments in various surface engineering strategies, antibacterial properties of Ti still need to be enhanced. Here a facile, cost-effective hydrothermal route was used to develop nano-patterned structures on a Ti surface. Changing hydrothermal treatment parameters such as temperature, pressure, and time, resulted in various topographies, crystal phases, and hydrophobicity. Specifically, hydrothermal treatment performed at 225 °C for 5 h, presented a novel topography with nanoflower features, exhibited no mammalian cell cytotoxicity for a time period of 14 days, and increased calcium deposition from osteoblasts. Treated samples also demonstrated antibacterial properties (without resorting to the use of antibiotics) against Staphylococcus aureus and methicillin resistant Staphylococcus aureus. In conclusion, hydrothermal oxidation on an etched Ti surface can generate surface properties that have excellent prospects for the biomedical field.


Assuntos
Materiais Biocompatíveis/farmacologia , Nanoestruturas/química , Temperatura , Titânio/farmacologia , Água/farmacologia , Cálcio/metabolismo , Morte Celular/efeitos dos fármacos , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Nanoestruturas/ultraestrutura , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Oxirredução , Molhabilidade , Difração de Raios X
4.
J Fluoresc ; 27(6): 2045-2050, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28748516

RESUMO

Here, we report the simple and cost effective colorimetric technique for the determination of toxic metals (Hg2+) in aqueous sample by using bioextract silver nanoparticles (AgNPs). The indigenous AgNPs were synthesised by green and ecologically friendly style using extract of fig (Ficus carica) leaf. The synthesized AgNPs were confirmed by UV-vis spectroscopy, FT-IR spectroscopy, and scanning electron microscopy methods. The synthesis of AgNPs was observed by its colour changing from light yellow to dark brownish. The existence of furanocoumarins bioactive materials in the fig leaf extract, which act as bio-reducing and capping agent, help in the formation of stabilized silver nanoparticles. In addition, the bacterial activity of the synthesized silver nanoparticles was tested against gram-negative (Klebsiella oxytocam, Pseudomonas aeruginosam, Shigella flexneri and Proteus mirabilis), gram-positive (Staphylococcus aureus and Micrococcus luteus) and one Candida (Candida albicans) human pathogen and the results showed moderate activity.


Assuntos
Antibacterianos/administração & dosagem , Bactérias/efeitos dos fármacos , Colorimetria/métodos , Mercúrio/toxicidade , Nanopartículas Metálicas/administração & dosagem , Prata/química , Antibacterianos/química , Humanos , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Extratos Vegetais/química
5.
J Inorg Organomet Polym Mater ; : 1-20, 2023 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-37359385

RESUMO

Role of synthetic coordination chemistry in pharmaceutical science is expeditiously increased due to its sundry relevances in this field. The present review endows the synthesized macrocyclic complexes of transition metal ions containing isatin and its derivatives as ligand precursors, their characterization and their copious pharmaceutical applications. Isatin (1H-Indole-2,3-dione) is a protean compound (presence of lactam and keto moiety permits to change its molecular framework) that can be obtained from marine animals, plants, and is also found in mammalian tissues and in human fluids as a metabolite of amino acids. It can be used for the synthesis of miscellaneous organic and inorganic complexes and for designing of drugs since it has remarkable utility in pharmaceutical industry due to its wide range of biological and pharmacological activities, for instance anti-microbial, anti-HIV, anti-tubercular, anti-cancer, anti-viral, anti-oxidant, anti-inflammatory, anti-angiogenic, analgesic activity, anti-Parkinson's disease, anti-convulsant etc. This review provides extensive information about the latest methods for the synthesis of isatin or its substituted derivatives based macrocyclic complexes of transition metals and their plentiful applications in medicinal chemistry.

6.
Micromachines (Basel) ; 14(7)2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37512635

RESUMO

Good water quality is essential for life; therefore, decolorizing and detoxifying organic dye wastes (textile effluents) have gained immense environmental importance in recent years. Thus, the degradation of wastewater has become a potential need for our environment. This research aims to synthesize and investigate a ceramic-based nanomaterial catalyst for the degradation of dye solution under exposure to sunlight. A reduced graphene oxide-ZnS (rGO-ZnS) nanomaterial was qualitatively synthesized using a solvothermal method. The prepared nanomaterial was characterized using XRD, SEM, HR-TEM, EDX, XPS, and FT-IR techniques. The photocatalytic activity of the rGO-ZnS nanomaterial was checked using oxidative photocatalytic degradation of naphthol blue black dye (NBB) under direct sunlight irradiation. Here, the rGO/ZnS composite showed a significant photocatalytic performance to degraded NBB (93.7%) under direct solar light. Chemical Oxygen Demand (COD) measurements confirmed the mineralization of the dye. The influence of different radical scavengers on NBB degradation was studied. Optimum conditions for efficient degradation were determined. The antibacterial property of the prepared catalyst was studied.

7.
Int J Biol Macromol ; 253(Pt 3): 126788, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37717862

RESUMO

In situ exfoliated natural polysaccharide Cordia myxa (CMX) is used to promote the utilization of zinc-oxide nanoparticles for eco-friendly catalytic hydrogenation of p-nitrophenol (p-NP) and microbial growth inhibition. Polysaccharide-mediated biosynthetic nanocomposite materials are interesting because they are cheap, green, and environmentally friendly. This study uses CMX gum as a bioreduction to produce multifunctional, environmentally friendly zinc-oxide nanocomposites (ZnO NPs). The process involves a low reaction time and temperature and utilizes CMX as a reducing and stabilizing agent. The structural, morphological, and optical properties of the CMX-ZnO nanocomposite were characterized. The biosynthetic CMX-ZnO NPs exhibited robust catalytic activity and recycling capacity for rapidly oxidizing hazardous p-NPs. The complete reduction of 4-NP to CMX-ZnO NPs in excess NaBH4 was achieved within 15 min, with recyclability and pseudo-first-order kinetics with a rate constant of 0.2571 min-1. Additionally, human colon cancer (HCT116) and 3T3L1 cell lines were remarkably sensitive to the cytotoxic effects of ZnO nanoparticles. CMX-ZnO NPs exhibited potent antibacterial properties against human pathogenic gram-positive and gram-negative bacteria (Bacillus, Salmonella, E. coli, and Pseudomonas aeruginosa) based on the zone of inhibition measured by the disc-diffusion method. The significant antibacterial activity of CMX-ZnO NPs can overcome the current limitations associated with removing water-soluble organic pollutants and microbiological contaminants for long-term environmental sustainability.


Assuntos
Cordia , Nanopartículas Metálicas , Nanopartículas , Óxido de Zinco , Humanos , Antibacterianos/química , Óxido de Zinco/química , Nanopartículas Metálicas/química , Bactérias Gram-Negativas , Escherichia coli , Bactérias Gram-Positivas , Antifúngicos/farmacologia , Nanopartículas/química , Nitrofenóis , Polissacarídeos/farmacologia , Zinco/farmacologia , Testes de Sensibilidade Microbiana , Extratos Vegetais/química
8.
Int J Mol Sci ; 13(4): 4982-4992, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22606024

RESUMO

A novel family of tetraaza macrocyclic Cu(II) complexes [CuLX(2)] (where L = N(4) donor macrocyclic ligands) and (X = Cl(-), NO(3) (-)) have been synthesized and characterized by elemental analysis, magnetic moments, IR, EPR, mass, electronic spectra and thermal studies. The magnetic moments and electronic spectral studies suggest square planar geometry for [Cu(DBACDT)]Cl(2) and [Cu(DBACDT)](NO(3))(2) complexes and distorted octahedral geometry to the rest of the ten complexes. The biological activity of all these complexes against gram-positive and gram-negative bacteria was compared with the activity of existing commercial antibacterial compounds like Linezolid and Cefaclor. Six complexes out of twelve were found to be most potent against both gram-positive as well as gram-negative bacteria due to the presence of thio group in the coordinated ligands.


Assuntos
Antibacterianos/farmacologia , Compostos Aza/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Compostos Macrocíclicos/farmacologia , Acetamidas/farmacologia , Antibacterianos/análise , Antibacterianos/química , Compostos Aza/análise , Compostos Aza/química , Cefaclor/farmacologia , Cobre/química , Linezolida , Compostos Macrocíclicos/análise , Compostos Macrocíclicos/química , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Oxazolidinonas/farmacologia , Espectrofotometria Infravermelho
9.
Spectrochim Acta A Mol Biomol Spectrosc ; 276: 121194, 2022 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-35378492

RESUMO

Indenocarbothioamides 2, obtained from reaction of indane-1,3-dione with aryl isothiocyanates, on condensation with 3-chloropentane-2,4-dione and chloroacetyl chloride furnished 1,3-indanedione coupled thiazole and thiazolidin-5-one derivatives, respectively. The structure of the obtained products was assigned on the basis of spectral data (IR, NMR and Mass). Prototropic tautomerism studies of carbothioamides 2 were carried out in solution (1H NMR, 13C NMR and UV-vis), gas phase (Mass) and solid state (IR and X-ray). X-ray diffraction studies of carbothioamide 2a have revealed the existence of enolic form in the solid state. DFT studies of various possible tautomeric forms in gas phase as well as in solution state corroborated by the experimental results. Antibacterial studies of indenothiazole and indenothiazolidin-5-one derivatives have been reported.


Assuntos
Modelos Moleculares , Espectroscopia de Ressonância Magnética , Difração de Raios X
10.
Environ Sci Pollut Res Int ; 29(36): 54318-54329, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35296999

RESUMO

This work describes the design of novel Cu(II) complexes and their application in the photocatalytic degradation of methylene blue (MB). The same photocatalyst exhibits antibacterial activity against Escherichia coli (gram-negative) and Bacillus circulans (gram-positive). The characterisation of the photocatalysts has been done by several up-to-date physical methods. The rationale behind the photocatalysts' beneficial intervention is discussed in this study. Statistical analysis of the degradation of MB is done using a one-way ANOVA, and the significance of means is determined by a multiple comparison test using Turkey HSD. Also, the degradation of MB follows pseudo first-order kinetics with high correlation coefficient values (R2 > 0.95), making them useful as simple and low-cost organic dye degradation agents.


Assuntos
Azul de Metileno , Bases de Schiff , Antibacterianos/farmacologia , Catálise , Corantes
11.
Heliyon ; 8(6): e09678, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35721680

RESUMO

The isomeric ligand LC, a saturated analogue of 2,9-C-meso-Me8[14]diene, on reflux with excess acrylonitrile afforded 1,8-N-pendant cyanoethyl derivative LCX. Interaction of LCX with cadmium(II) perchlorate, nitrate, acetate, and chloride salts produced six coordinated octahedral compounds, [Cd(LCX) (ClO4)2]∙2H2O, [Cd(LCX) (NO3)2], [Cd(LCX) (CH3COO)2], and [Cd(LCX)Cl2], respectively. Further, axial substitution reactions between [Cd(LCX) (ClO4)2]∙2H2O and KI, KBr, KCl, KSCN, and NaNO2 in a 1:2 ratio yielded six coordinated octahedral compounds, [Cd(LCX)I2]∙H2O, [Cd(LCX)Br2]∙2H2O, [Cd(LCX)Cl(ClO4)]∙2H2O, [Cd(LCX) (NCS)2]∙H2O, and [Cd(LCX) (NO2) (ClO4)]∙2H2O, respectively. All of the newly prepared compounds have been characterized by analytical, spectroscopic, molar conductivity, and magnetochemical data. The crystal structure of the ligand LCX was determined by x-ray crystallography which showed the 14-membered ring to adopt an extended chair conformation. Antibacterial activities of the newly formed cadmium(II) complexes against selected bacteria showed these to exhibit moderate and selective activity with 1-4 and 8 exhibiting greatest potency against the gram negative bacterium Salmonella typhi, and 5, 6, and 7 against the gram positive bacterium Bacillus wiedmannii.

12.
Biomedicines ; 10(9)2022 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-36140329

RESUMO

This paper presents pioneering results on the evaluation of noble metal film hetero-structures to improve some functional characteristics of carbon-based implant materials: carbon-composite material (CCM) and carbon-fiber-reinforced polyetheretherketone (CFR-PEEK). Metal-organic chemical vapor deposition (MOCVD) was successfully applied to the deposition of Ir, Pt, and PtIr films on these carriers. A noble metal layer as thin as 1 µm provided clear X-ray imaging of 1−2.5 mm thick CFR-PEEK samples. The coated and pristine CCM and CFR-PEEK samples were further surface-modified with Au and Ag nanoparticles (NPs) through MOCVD and physical vapor deposition (PVD) processes, respectively. The composition and microstructural features, the NPs sizes, and surface concentrations were determined. In vitro biological studies included tests for cytotoxicity and antibacterial properties. A series of samples were selected for subcutaneous implantation in rats (up to 3 months) and histological studies. The bimetallic PtIr-based heterostructures showed no cytotoxicity in vitro, but were less biocompatible due to a dense two-layered fibrous capsule. AuNP heterostructures on CFR-PEEK promoted cell proliferation in vitro and exhibited a strong inhibition of bacterial growth (p < 0.05) and high in vitro biocompatibility, especially Au/Ir structures. AgNP heterostructures showed a more pronounced antibacterial effect, while their in vivo biocompatibility was better than that of the pristine CFR-PEEK, but worse than that of AuNP heterostructures.

13.
BMC Chem ; 15(1): 42, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193227

RESUMO

BACKGROUND: Silver orthophosphate (Ag3PO4) has received enormous attention over the past few years for its higher visible light photocatalytic performance as well as for various organic pollutants degradation in aqueous media. Therefore, considerable efforts have been made to the synthesis of Ag3PO4 with high catalytic efficiency, long lifetime, and using low-cost inorganic precursors. RESULTS: This article describes our efforts to develop a novel approach to synthesize of nanostructured silver phosphate (Ag3PO4) using phosphate rock as alternative and natural source of PO43- precursor ions. The catalytic experimental studies showed that the nanostructured Ag3PO4 exhibited excellent catalytic activity for reduction of p-nitrophenol in the presence of NaBH4 at room temperature. Furthermore, the antibacterial studies revealed that the obtained Ag3PO4 possess significant effect against E. Coli and S. Aureus bacteria. CONCLUSION: The obtained results make the nanostructured Ag3PO4 prepared from natural phosphate as a highly promising candidate to be used as efficient catalyst and antibacterial agent.

14.
J Hazard Mater ; 402: 123560, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-32759001

RESUMO

Production of multi-functional zinc oxide nanoparticles (ZnO-NPs) for wastewater treatment through green-approaches is a desirable alternative for conventional synthesis routes. Biomass waste valorization for nanoparticles synthesis has received increased research attention. The present study reports date pulp waste (DPW) utilization as an effective bio-reductant for green-synthesis of ZnO-NPs. A simple and eco-friendly process with low reaction time and calcination temperature was adopted for DPW mediated ZnO-NPs (DP-ZnO-NPs) synthesis. Microscopic investigations of DP-ZnO-NPs confirmed the non-agglomeration and spherical nature of particles with mean diameter of 30 nm. EDX and XPS analysis defined the chemical composition and product purity of DP-ZnO-NPs. UV and photoluminescence studies exhibited surface plasmonic resonance at 381 nm and fluorescent nature of DP-ZnO-NPs. FTIR studies established a formation mechanism outline for DP-ZnO-NPs. XRD and Raman investigations confirmed the crystalline and hexagonal wurtzite phase of DP-ZnO-NPs. DSC/TG analysis displayed the thermal stability of DP-ZnO-NPs with <10 wt% loss upto 700 °C. Photocatalytic degradation of hazardous methylene blue and eosin yellow dyes using DP-ZnO-NPs, showed rapid decomposition rate with 90 % degradation efficiency. Additionally, DP-ZnO-NPs demonstrated significant antibacterial effects on various pathogenic bacteria in terms of zone-of-inhibition measured by disc-diffusion method. Thus, the as-prepared DP-ZnO-NPs is suitable for industrial wastewater treatment.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Phoeniceae , Purificação da Água , Óxido de Zinco , Antibacterianos , Química Verde , Testes de Sensibilidade Microbiana
15.
Nanomaterials (Basel) ; 11(11)2021 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-34835682

RESUMO

Due to modernization and the scarcity of fossil fuel resources, energy demand is continuously increasing. In this regard, it is essential and necessary to create a renewable energy source that can meet future energy demands. Recently, the production of H2 by water splitting and removing pollutants from the water has been essential for issues of energy and environmental demands. Herein, g-C3N4 and Ag-g-C3N4 composite structures have been successfully fabricated by the ultrasonication method. The physio/photochemical properties of prepared g-C3N4 and Ag-g-C3N4 were examined with different analytical techniques such as FTIR, XRD, UV-DRS, SEM, TEM, PL, and XPS analyses. The silver quantum dots (QDS) anchored to g-C3N4 structures performed the profound photocatalytic activities of H2 production, dye degradation, and antimicrobial activity under visible-light irradiation. The Ag/g-C3N4 composite with an Ag loading of 0.02 mole has an optimum photoactivity at 335.40 µmol g-1 h-1, which is superior to other Ag loading g-C3N4 composites. The synthesized Ag/g-C3N4 nanoparticles showed potential microbial inhibition activity during the preliminary screening, and the inhibition zones were comparable to the commercial antibiotic chloramphenicol. The loading of Ag into g-C3N4 paves the suppression, recombination and transfer of photo-generated electron-hole pairs, leading to the enhancement of hydrogen production, the diminishment of pollutants in water under visible light irradiation, and antimicrobial activity against multidrug-resistant pathogens.

16.
Spectrochim Acta A Mol Biomol Spectrosc ; 230: 118064, 2020 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-31955124

RESUMO

Positional isomers of benzothiazole-pyridone and benzothiazole-pyrazole containing disperse azo dyes are reported. These heterocyclic azo dyes are decorated with 'separate ESIPT core' and show emission in seven solvents of different polarity. After application on polyester fabric, "very good to excellent" light and washing fastness properties were observed. Thermal stability of 'dyed fabric' was analysed by sublimation fastness test- and found 'very good to excellent' ratings at 210 °C. Ultraviolet Protection Factor (UPF) analysis of four 'dyed fabric' indicates the blocking 96-97% of UV radiation. Dyes were found effective on gram positive and negative bacteria by agar diffusion method and all the 'dyed fabrics' also showed more than 92% or 94% reduction of S. aureus or K. pneumoniae respectively by 'AATCC 100' method. Structures of the dyes were optimized using Density Functional Theory (DFT) to deduce stable tautomeric form. Calculated HOMO-LUMO gap is then compared with antibacterial activities. Electrophilicity index and lightfastness property were also compared and found to have very good correlation.


Assuntos
Compostos Azo/química , Benzotiazóis/química , Poliésteres/química , Piridonas/química , Têxteis , Antibacterianos/química , Humanos , Infecções por Klebsiella/prevenção & controle , Klebsiella pneumoniae/efeitos dos fármacos , Pirazóis/química , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/efeitos dos fármacos , Fator de Proteção Solar , Indústria Têxtil , Têxteis/análise
17.
J Photochem Photobiol B ; 187: 25-34, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30096540

RESUMO

The effect of surfactant and dopant on the properties of zinc oxide nanoparticles were studied by preparing polyethylene glycol (PEG) capped ZnO and tungsten doped PEG capped ZnO nanoparticles via the electrochemical method. These nanoparticles were characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet Diffuse Reflection Spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM) and Electron Dispersive Analysis of X Rays (EDAX). The photocatalytic degradation of malachite green dye using these nanoparticles was studied under visible light. The effects of various reaction parameters like dye concentration, catalyst concentration, pH and time were studied to optimize the photodegradation reaction. Reusability of these nanoparticles was studied and no significant change was observed in the degradation efficiency of PEG capped ZnO till the fourth cycle, while there was a gradual decrease in the degradation efficiency of tungsten doped PEG capped ZnO. Langmuir- Hinshelwood kinetic model well describes the photodegradation capacity and the degradation of malachite green follows pseudo-first order kinetics.Photocatalytic studies reveal that PEG capping increases the degradation properties of ZnO while tungsten doping decreases the extent of PEG capping and has a detrimental effect on the degradation properties of ZnO. The prepared nanoparticles exhibit significant antibacterial properties against gram-positive Bacillus cereus and gram-negative Escherichia coli bacterial strains by agar well diffusion method.


Assuntos
Antibacterianos/síntese química , Nanopartículas Metálicas/química , Polietilenoglicóis/química , Óxido de Zinco/química , Antibacterianos/química , Antibacterianos/farmacologia , Bacillus cereus/efeitos dos fármacos , Catálise , Corantes/química , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Técnicas Eletroquímicas , Escherichia coli/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Luz , Nanopartículas Metálicas/toxicidade , Microscopia Eletrônica de Varredura , Fotólise/efeitos dos fármacos , Fotólise/efeitos da radiação , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Tungstênio/química , Difração de Raios X
18.
J Photochem Photobiol B ; 173: 466-475, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28668515

RESUMO

The ZnO thin films have been prepared by spin coating followed by annealing at different temperatures like 300°C, 350°C, 400°C, 450°C, 500°C & 550°C and ZnO nanoparticles have been used for photocatalytic and antibacterial applications. The morphological investigation and phase analysis of synthesized thin films well characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Photoluminescence (PL), Transmission Electron Microscopy (TEM) and Raman studies. The luminescence peaks detected in the noticeable region between 350nm to 550nm for all synthesized nanosamples are associated to the existence of defects of oxygen sites. The luminescence emission bands are observed at 487nm (blue emission), and 530nm (green emission) at the RT. It is observed that there are no modification positions of PL peaks in all ZnO nanoparticles. In the current attempt, the synthesized ZnO particles have been used photocatalytic and antibacterial applications. The antibacterial activity of characterized samples was regulated using different concentrations of synthesized ZnO particles (100µg/ml, 200µg/ml, 300µg/ml, 400µg/ml, 500µg/ml and 600µg/ml) against gram positive and gram negative bacteria (S. pnemoniae, S. aureus, E. coli and E. hermannii) using agar well diffusion assay. The increase in concentration, decrease in zone of inhibition. The prepared ZnO morphologies showed photocatalytic activity under the sunlight enhancing the degradation rate of Rhodamine-B (RhB), which is one of the common water pollutant released by textile and paper industries.


Assuntos
Antibacterianos/farmacologia , Materiais Revestidos Biocompatíveis/química , Óxido de Zinco/química , Antibacterianos/síntese química , Catálise , Materiais Revestidos Biocompatíveis/farmacologia , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Bactérias Gram-Negativas/efeitos da radiação , Bactérias Gram-Positivas/efeitos da radiação , Medições Luminescentes , Microscopia Eletrônica de Varredura , Fotólise/efeitos da radiação , Rodaminas/química , Luz Solar
19.
J Colloid Interface Sci ; 504: 164-170, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28550746

RESUMO

Pure and zinc-doped CdO NPs (Zn-CdO NPs) were synthesized through a facile co-precipitation method. The structural, morphology, chemical composition, optical and antibacterial activity of the NPs were studied with respect to pure and Zn-doped CdO concentration (0-7.5mol.%). Scanning electron microscope (SEM) images reveal that pure and Zn-doped CdO NPs were in the nano-scale regime with different crystalline morphology. The energy dispersive X-ray spectroscopy (EDS) spectrum predicts the presence of Cadmium (Cd), Zinc (Zn) and Oxygen (O) in the prepared samples. Optical studies divulge that Zn2+ doping CdO decreases the band gap energy (Eg) (3.36-3.02eV) with an increase in Zn2+ doping concentration. Optical absorption spectrum of CdO red-shifted as the Zn concentration varied from 2.5mol.% to 7.5mol.%. PL spectra displayed a strong UV emission peak at 380nm. Enhanced Visible emission at 430 and 522nm with Zn2+ doping interprets the defect density in CdO by occupying Cd2+ vacancies with Zn2+ ions. Photocatalytic studies revealed that 7.5% Zn-doped CdO NPs show maximum degradation for atrazine (ATZ) as herbicide pollution under UV irradiation. Antibacterial studies against (Gram positive) and (Gram negative) bacteria's authenticate that Zn2+ doped CdO nanostructures exhibit excellent antibacterial activity against all bacteria's with an increase in doping concentration.


Assuntos
Antibacterianos/química , Compostos de Cádmio/química , Nanopartículas/química , Óxidos/química , Zinco/química , Antibacterianos/farmacologia , Atrazina/química , Bactérias/efeitos dos fármacos , Infecções Bacterianas/prevenção & controle , Compostos de Cádmio/farmacologia , Catálise , Humanos , Óxidos/farmacologia , Praguicidas/química , Fotólise , Raios Ultravioleta , Zinco/farmacologia
20.
J Photochem Photobiol B ; 177: 62-68, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29069633

RESUMO

Green synthesis of silver nanoparticles (Ag NPs) using an extract of dried Zingiber officinale (ginger) root as a reducing and capping agent in the presence of microwave irradiation was herein reported for the first time. The formation of symmetrical spheres is confirmed from the UV-Visible spectrum of Ag NPs. Fourier transform infra-red spectroscopy confirms the formation of the Ag NPs. X-ray diffraction analysis was utilized to calculate the crystallite size of Ag NPs and the value was found to be 10nm. High-resolution transmission electron microscopy and high-resolution scanning electron microscopy were used to investigate the morphology and size of the synthesized samples. The sphere like morphology is confirmed from the images. The purity and crystallinity of Ag NPs is confirmed by energy-dispersive X-Ray analysis and selected area electron diffraction respectively. The electrochemical behavior of the synthesized Ag NPs was assessed by cyclic voltammetry (CV) and shows the redox peaks in the potential range of -1.1 to +1.1V. Agar diffusion method is used to examine the antibacterial activity of Ag NPs. For this purpose, two gram positive and two gram negative bacteria were studied. This single step approach was found to be simple, short time, cost-effective, reproducible, and eco-friendly.


Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Química Verde , Nanopartículas Metálicas/química , Prata/química , Zingiber officinale/química , Antibacterianos/química , Técnicas Eletroquímicas , Zingiber officinale/metabolismo , Bactérias Gram-Negativas/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Extratos Vegetais/química , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
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