Papers by Keyword: Antibacterial

Abstract: CuSO₄-deposited and CuO-deposited polyurethane foam (PUF) were fabricated in this study. Image analysis showed color transformation of the PUF from yellow to blue-green, which is indicative of the deposited CuSO₄ particles on the substrate. Further color transformation of the material from blue-green to greenish-brown after soaking in NaOH suggest that the CuSO₄ oxidized to form CuO, which was confirmed by the presence of CuO peaks during XRD analysis. SEM images also reveal the presence of CuO rods embedded in the PUF. The antibacterial activities of the CuSO_4- and CuO-deposited samples against the gram-negative Escherichia coli bacteria were conducted.

Abstract: Titanium dioxide is prepared by sol gel method from titanium tetraisopropoxide (TTIP) as precursor and likewise zinc oxide is prepared by sol gel method from zinc acetate dehydrate (ZAD) as precursor. The composite sols are prepared in three different molar ratios 90TiO2:10ZnO, 70TiO2:30ZnO and 50TiO2:50ZnO. Thin film deposition is carried out by dip coating technique. Crystal structure, surface morphology and photocatalytic activity of the prepared nanocomposite thin films are investigated. The antibacterial activity of the prepared nanocomposite thin film against E-coli ATCC 25922 bacteria is examined by placing the thin film in standard aqueous E-coli medium under UV light for 1, 2, 3 and 4 hours and then counting the bacteria with Standard Plate Count Agar (SPC) technique. The prepared thin films have shown strong antibacterial activity in the presence of UV light and by increasing the ZnO molar ratio from 10 to 50, antibacterial activity of the thin films decreases because of decreases in the anatase phase of the TiO2. In the dark conditions by increasing the molar ratio of ZnO, the antibacterial activity of the thin films increases and this phenomenon is related to increasing the zinc ions in the thin films.

Abstract: Prepared and heat-treated sol-gel ZnO-TiO₂ coatings onto microscope glass slides were characterised by atomic force microscopy (AFM), scanning electron microscopy (SEM), as well as absorption spectra of light has been obtained. Thermally treated xerogels were characterised by X-ray diffraction (XRD). As well as their photocatalytic activity using methyl orange (MO) and observing the colour changes over the time in visible light (VIS) and ultra violet (UV) light has been determined. The influence of ZnO concentration on morphology, photocatalytic activity and antibacterial properties of coatings was analysed. The growth of S. epidermidis on the surface of the samples was inhibited due to photocatalytic properties of coatings.

Abstract: Titanate Ribbon (Na₂Ti₃O₇) used in ABS plastic was synthesized to study the mechanical properties and to conduct test on the E-coli bacteria inhibition performance. The polymer blends of ABS/Na₂Ti₃O₇ by Na₂Ti₃O₇, was synthesized through alkaline hydrothermal reaction with 0.5 grams of titanium dioxide as a precursor with 20 ml. of sodium hydroxide (NaOH) at the concentration of 10 molar under the alkalinity at 200 ° c for 24 hours. The study on the microstructure by scanning electron microscope revealed that the Layered structure was shaped as a complete ribbon. The mechanical testing activities on the E-coli bacteria inhibition polymer mixed ABS/Na₂Ti₃O₇; it was found that the mechanical properties for ABS/Na₂Ti₃O₇, The results showed that tensile modulus and tensile strength of blending Na₂Ti₃O₇ at 0.5 %wt was the highest. The result showed that E.coli could reduce up to 66.01%.

Abstract: Some novel N-phenylpyrazolines were synthesized and investigated for their antibacterial activitiy. Chalcones 2-4 which were prepared from acetophenone and veratraldehyde derivatives were reacted with phenylhydrazine to give N-phenylpyrazolines 5-7. All of the synthesized compounds were characterized using FTIR, GC-MS, and NMR spectrometers. Further, antibacterial activity of N-phenylpyrazolines were evaluated by agar well-diffusion method against Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Escherichia coli, and Shigella flexneri. The highest activity (highest inhibition zone) of compound 5 was 2.6 mm (at 1000 ppm) against B. subtillis, compound 6 was 7.25 mm (at 1000 ppm) against S. aureus, and compound 7 was 6.75 mm (at 500 ppm) against S. aureus. The results indicated that compound 6 and 7 exhibited promising antibacterial activity.

Abstract: Due to its excellent mechanical property, dye ability and skin affinity, PA6 has been widely used in apparel, home textiles, military products, etc. However, PA6 fiber is easy to breed bacteria and corroded by bacteria in humid environment. One of development tendency of functional PA6 fiber is to design and develop nylon 6 fiber with excellent antibacterial properties, which is also the research target of this paper. In the present investigation, ZnO antibacterial agent was prepared through sol-gel method, and antibacterial masterbatch was acquired via blending antibacterial agent with PA6 using a twin-screw, then antibacterial PA6 fiber was obtained through melt spinning. The thermal properties, crystallization property of antibacterial PA6 masterbatch were discussed. The effect of drawing ratio on fiber strength, elongation of break, orientation and crystallization was also investigated. The antibacterial properties of antibacterial agent and antibacterial PA6 fiber was analyzed by agar diffusion method. The results of Differential Scanning Calorimetry (DSC) suggests that the antibacterial agent causes the rise of crystallization temperature and crystallization rate. X-Ray Diffraction (XRD) and mechanical testing results reveal that the higher drawing ratio leads to higher orientation and strength of PA6 fiber, lower elongation at break. The addition of antibacterial agent increases the degree of orientation and crystallization, reduces the strength of fiber and tends to form α crystalline in PA6 fiber. Antibacterial tests show that antibacterial PA6 fiber has a good antibacterial performance against Staphylococcus aureus.

Abstract: The aim of this present work is to enhance photoantibacterial performance on a surface of Acrylonitrile-Butadiene-Styrene (ABS) by mixing titanium dioxide (TiO₂). The influences of different ratios for TiO₂ under UV light irradiation were investigated according to JIS Z 2801: 2010 standard. 0.5%, 1% and 2% TiO₂/ABS were formed by melting process with internal mixer and compression molding process. E.coli were chosen as a model of bacteria. The best photoantibacterial activity was provided by 0.5% TiO₂/ABS. The result showed that E.coli could reduce up to 46.95%. However, a higher amount of TiO₂ (i.e., 1% and 2% TiO₂/ABS) obstructed the reaction, and E.coli was reduced to 42.6% and 36.08%, respectively. This was due to its aggregation observed from SEM image. For mechanical properties for TiO₂/ABS, The results showed that tensile modulus and tensile strength of blending TiO₂ at 0.5 %wt was the highest but the tensile was decreased when increasing TiO₂ in polymer blended.

Abstract: This study aims to describe the influence of adding graphene oxide to TiO₂-noble metal (Me=Ag, Au or Pd) composite nanoparticles on their bioactivity (formation of RGO/TiO₂-Me nanocomposite system). The obtained nanocomposite flakes and reference TiO₂-Me nanoparticles were characterized using SEM, HRTEM and XPS spectroscopy, N₂ sorption analysis and helium pycnometer. The analysis of the antibacterial properties of synthesized nanocomposites revealed a growth inhibiting effect of TiO₂-Ag particles on gram positive bacteria such as: Staphylococcus aureus, Sarcina lutea and Bacillus subtilis. In the case of nanocomposite flakes containing RGO the visible changes in bacteriostatic properties were observed, including unexpected reversal of the antimicrobial activity of silver-containing nanoparticles into the stimulation of growth of applied bacterial strains. The stimulation of growth was not observed for TiO₂-Au and Pd nanoparticles deposited on the surface of RGO.

Abstract: The aim of this study was to compare the bioactivity of RGO/ceramic oxide-Ag nanocomposites. Different ceramic oxides (Me_xO_y) i.e.: Al₂O₃, TiO₂, SiO₂ and ZnO₂ were in situ co-deposited with Ag nanoparticles on the surface of RGO resulting in the formation of a nanocomposite structure of stacked flakes. The results of our investigations indicate that it is possible to obtain the targeted biocidal properties of the RGO/Ag system by choosing the appropriate ceramic oxide as a modificator of Ag nanoparticles. The strongest antimicrobial properties against E. coli, S. aureus and Bacillus sp. strains were achieved for RGO/SiO₂-Ag nanocomposite whereas for Sarcina sp. bacteria the most effective biocide was RGO/TiO₂-Ag nanocomposite.

Abstract: PMMA/nanoCu antibacterial plastic was prepared by in situ polymerization using MMA as monomer, BPO as initiator and surface treated nanoCu as antibacterial agent. AMEO was used for surface treatment of nanoCu. ATR-FTIR spectra showed that AMEO successfully reacted on the surface of nanoCu. SEM spectra showed that nanoCu dispersed evenly in the PMMA/nanoCu composite. Antibacterial test results showed that the composite had a strong antibacterial effect on Escherichia coli, and the antibacterial rate reached more than 99%. Therefore, the PMMA/nanoCu composite can be used in various fields of antibacterial plastic products.