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Le A.-T.,Hanoi University | Tam L.T.,Hanoi University | Tam P.D.,Hanoi University | Huy P.T.,Hanoi University | And 4 more authors.
Materials Science and Engineering C | Year: 2010

The development of new and simple green chemical methods for synthesizing colloidal solutions of functional nanoparticles is desirable for environment-friendly applications. In the present work, we report a feasible method for synthesizing colloidal solutions of silver nanoparticles (Ag NPs) based on the modified Tollens technique. The Ag NPs were stabilized by using oleic acid as a surfactant and were produced for the first time by the reduction of silver ammonium complex [Ag(NH3)2]+ (aq) by glucose with UV irradiation treatment. A stable and nearly monodisperse aqueous Ag NPs solution with average-sized particles (~ 9-10 nm) was obtained. The Ag NPs exhibited high antibacterial activity against both Gram-negative Escherichia Coli (E. coli) and Gram-positive Staphylococcus aureus bacteria. Electron microscopic images and analyses provided further insights into the interaction and bactericidal mechanism of the Ag NPs. The proposed method of synthesis is an effective way to produce highly bactericidal colloidal solutions for medical, microbiological, and industrial applications. © 2010 Elsevier B.V. Source


Tam P.D.,Hanoi University | Tuan M.A.,Hanoi University | Huy T.Q.,National Institute of Hygiene and Epidemiology NIHE | Le A.-T.,Hanoi University | Hieu N.V.,Hanoi University
Materials Science and Engineering C | Year: 2010

In this paper, a simple DNA sensor platform was developed for rapid herpes virus detection in real samples. The deoxyribonucleic acid (DNA) sequences of the herpes simplex virus (DNA probe) were directly immobilized on the surface of interdigitated electrodes by electrochemical polymerization along with pyrrole monomers. The potential was scanned from - 0.7 to + 0.6 V, and the scanning rate was 100 mV/s. Fourier transform infrared spectroscopy was employed to verify specific DNA sequence binding and the conducting polymer. The morphology of the conducting polymer doped with DNA strands was characterized using a field emission scanning electron microscope. As-obtained DNA sensor was used to detect the herpes virus DNA in the real samples. The results show that the current DNA sensors detected the lowest DNA concentration of 2 nM. This sensitivity appears to be better than that of the DNA sensors prepared by immobilization of the DNA probe on the 3-aminopropyl-triethoxy-silance (APTS) membrane. © 2010 Elsevier B.V. Source


Bettarel Y.,Montpellier University | Thuy N.T.,National Institute of Hygiene and Epidemiology NIHE | Huy T.Q.,National Institute of Hygiene and Epidemiology NIHE | Hoang P.K.,Vietnamese National Institute of Oceanography VNIO | Bouvier T.,Montpellier University
Journal of the Marine Biological Association of the United Kingdom | Year: 2013

Virus-like particles were observed in thin sections of partially bleaching colonies of the scleractinian Acropora cytherea, collected in the Hon Mun Marine Protected Area (Vietnam). The most common particles were found in the cytoplasm of epidermal cells, exhibiting icosahedral symmetry and measuring 90-140 nm in diameter. Some had a tail-like structure resembling that of certain Hepadnaviridae such as the hepatitis B virus. Some others were tailless with a virion size. Overall, less than 10% of the cells showed obvious signs of infection. Images of virally-parasitized tissues of A. cytherea provide further evidence that corals are a target for viral infection. However, more research is required into their pathogenicity and involvement in bleaching events. Copyright © Marine Biological Association of the United Kingdom 2012. Source


Nga N.K.,Hanoi University of Science and Technology | Hong P.T.T.,Hanoi University of Science and Technology | Lam T.D.,Vietnam Academy of Science and Technology | Huy T.Q.,National Institute of Hygiene and Epidemiology NIHE
Journal of Colloid and Interface Science | Year: 2013

Magnesium oxide (MgO) has been known as an excellent adsorbent for a variety of the environmentally polluted compounds. This work describes a synthesis of nanostructured MgO particles via a facile procedure by using cetyltrimethylammonium bromide (CTAB). Powder X-ray diffraction, thermal gravimetric, and differential thermal gravimetry (TGA/DTG) analyses were performed to characterize the physical properties of synthesized MgO particles and field emission-scanning electron microscopy (FE-SEM) was used to observe their morphology, whereas nitrogen adsorption-desorption isotherms and Brunauer-Emmett-Teller (BET) method were used to calculate the total surface areas of the samples. The adsorptive performance was studied by batch experiments for reactive blue (RB) 19 dye removal. The results showed that as-prepared MgO particles revealed hexagonal-like shaped platelets with an average diameter in the range of 49-91nm and a mean thickness of 19-25nm; meanwhile, MgO CTAB-free particles are aggregated, tiny nanoparticles with an average width of 22nm and an average length of 77nm. The maximum adsorption capacity of as-prepared nanostructured MgO for reactive blue (RB) 19 dye was 250mgg-1. Furthermore, the correlation between structural characterization (mean size, pore, surface) of the samples and the adsorption performance was also discussed in details. © 2013 Elsevier Inc. Source


van Tuan C.,Hanoi University of Science and Technology | Huy T.Q.,National Institute of Hygiene and Epidemiology NIHE | Van Hieu N.,Hanoi University of Science and Technology | Tuan M.A.,Hanoi University of Science and Technology | Trung T.,Hung Yen University of Technology and Education
Analytical Letters | Year: 2013

Polyaniline (PANI) conducting polymers have attracted increasing interest as a transducer material for biosensors applications. In this study, we demonstrate the use of PANI nanowires (NWs) as immobilization platforms in the configuration of an electrochemical immunosensor for label free detection of Japanese encephalitis virus. The PANI NWs were synthesized on the surface of an interdigitated platinum (Pt) microelectrode via electrochemical growth. The morphology and characteristics of the PANI NWs on the Pt microelectrode were verified by scanning electron microscopy and Fourier transform infrared spectroscopy. The anti- Japanese encephalitis virus polyclonal IgG antibody was then covalently immobilized on the PANI NWs-coated Pt microelectrode by using 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimde (NHS). The detection of Japanese encephalitis virus antigens was analyzed by electrochemical impedance spectroscopy (EIS). The developed PANI NWs-based electrochemical immunosensor could detect the Japanese encephalitis virus with a detection limit below 10 ng/ml. The results from EIS analysis also indicate that when the PANI NWs were exposed to nonspecific molecules, a negligible response was found, and it did not impact to the specificity of the sensor in the virus detection. This work shows the potential use of PANI NWs in electrochemical immunosensors for label free detection of other pathogens and small biomolecules. © 2013 Copyright Taylor and Francis Group, LLC. Source

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