Browsing by Author "Padil, Vinod Vellora Thekkae"

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    Fabrication, Characterization, and Antibacterial Properties of Electrospun Membrane Composed of Gum Karaya, Polyvinyl Alcohol, and Silver Nanoparticles
    (Hindawi Publishing Corporation, 2015-01-01) Padil, Vinod Vellora Thekkae; Nguyen, Nhung H. A.; Ševců, Alena; Černík, Miroslav
    Gum karaya (GK), a natural hydrocolloid, was mixed with polyvinyl alcohol (PVA) at different weight ratios and electrospun to produce PVA/GK nanofibers. An 80 : 20 PVA/GK ratio produced the most suitable nanofiber for further testing. Silver nanoparticles (Ag-NPs) were synthesised through chemical reduction of AgNO3 (at different concentrations) in the PVA/GK solution, the GK hydroxyl groups being oxidised to carbonyl groups, and Ag+ cations reduced to metallic Ag-NPs. These PVA/GK/Ag solutions were then electrospun to produce nanofiber membranes containing Ag-NPs (Ag-MEMs). Membrane morphology and other characteristics were analysed using scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, and UV-Vis and ATR-FTIR spectroscopy. The antibacterial activity of the Ag-NP solution and Ag-MEM was then investigated against Gram-negative Escherichia coli and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. Our results show that electrospun nanofiber membranes based on natural hydrocolloid, synthetic polymer, and Ag-NPs have many potential uses in medical applications, food packaging, and water treatment.
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    Green synthesis of copper oxide nanoparticles using gum karaya as a biotemplate and their antibacterial application
    (Dove Medical Press Ltd, 2013-01-01) Padil, Vinod Vellora Thekkae; Černík, Miroslav
    Background: Copper oxide (CuO) nanoparticles have attracted huge attention due to catalytic, electric, optical, photonic, textile, nanofluid, and antibacterial activity depending on the size, shape, and neighboring medium. In the present paper, we synthesized CuO nanoparticles using gum karaya, a natural nontoxic hydrocolloid, by green technology and explored its potential antibacterial application. Methods: The CuO nanoparticles were synthesized by a colloid-thermal synthesis process. The mixture contained various concentrations of CuCl2 center dot 2H(2)O (1 mM, 2 mM, and 3 mM) and gum karaya (10 mg/mL) and was kept at 75 degrees C at 250 rpm for 1 hour in an orbital shaker. The synthesized CuO was purified and dried to obtain different sizes of the CuO nanoparticles. The well diffusion method was used to study the antibacterial activity of the synthesized CuO nanoparticles. The zone of inhibition, minimum inhibitory concentration, and minimum bactericidal concentration were determined by the broth microdilution method recommended by the Clinical and Laboratory Standards Institute. Results: Scanning electron microscopy analysis showed CuO nanoparticles evenly distributed on the surface of the gum matrix. X-ray diffraction of the synthesized nanoparticles indicates the formation of single-phase CuO with a monoclinic structure. The Fourier transform infrared spectroscopy peak at 525 cm(-1) should be a stretching of CuO, which matches up to the B-2u mode. The peaks at 525 cm(-1) and 580 cm(-1) indicated the formation of CuO nanostructure. Transmission electron microscope analyses revealed CuO nanoparticles of 4.8 +/- 1.6 nm, 5.5 +/- 2.5 nm, and 7.8 +/- 2.3 nm sizes were synthesized with various concentrations of CuCl2 center dot 2H(2)O (1 mM, 2 mM, and 3 mM). X-ray photoelectron spectroscopy profiles indicated that the O 1s and Cu 2p peak corresponding to the CuO nanoparticles were observed. The antibacterial activity of the synthesized nanoparticles was tested against Gram-negative and positive cultures. Conclusion: The formed CuO nanoparticles are small in size (4.8 +/- 1.6 nm), highly stable, and have significant antibacterial action on both the Gram classes of bacteria compared to larger sizes of synthesized CuO (7.8 +/- 2.3 nm) nanoparticles. The smaller size of the CuO nanoparticles (4.8 +/- 1.6 nm) was found to be yielding a maximum zone of inhibition compared to the larger size of synthesized CuO nanoparticles (7.8 +/- 2.3 nm). The results also indicate that increase in precursor concentration enhances an increase in particle size, as well as the morphology of synthesized CuO nanoparticles.
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    Hydrocolloid-Stabilized Magnetite for Efficient Removal of Radioactive Phosphates
    (Hindawi Publishing Corporation, 2014-01-01) Padil, Vinod Vellora Thekkae; Rouha, Michael; Černík, Miroslav
    Liquid radioactive waste is a common by-product when using radioactive isotopes in research and medicine. Efficient remediation of such liquid waste is crucial for increasing safety during the necessary storage of the material. Herein, we present a novel Gum Karaya stabilized magnetite for the efficient removal of radioactive phosphorus P-32 from liquid radioactive waste. This environmentally friendly material is well suited to be used as a nanohydrogel for the removal of liquid waste, which can then be stored in a smaller space and without the risk of the spills inherent to the initial liquid material. The maximum adsorption capacity of the GK/M in this study was found to be 15.68GBq/g. We present a thorough morphological characterization of the synthesised GK/M, as well as a discussion of the possible phosphorus adsorption mechanisms.