Now showing 1 - 3 of 3
  • Publication
    A portable automatic endpoint detection system for amplicons of loop mediated isothermal amplification on microfluidic compact disk platform
    ( 2015)
    Shah Uddin
    ;
    Fatimah Ibrahim
    ;
    Abkar Sayad
    ;
    Aung Thiha
    ;
    Koh Pei
    ;
    Mas Mohktar
    ;
    ;
    Jongman Cho
    ;
    Kwai Thong
    In recent years, many improvements have been made in foodborne pathogen detection methods to reduce the impact of food contamination. Several rapid methods have been developed with biosensor devices to improve the way of performing pathogen detection. This paper presents an automated endpoint detection system for amplicons generated by loop mediated isothermal amplification (LAMP) on a microfluidic compact disk platform. The developed detection system utilizes a monochromatic ultraviolet (UV) emitter for excitation of fluorescent labeled LAMP amplicons and a color sensor to detect the emitted florescence from target. Then it processes the sensor output and displays the detection results on liquid crystal display (LCD). The sensitivity test has been performed with detection limit up to 2.5 × 10−3 ng/µL with different DNA concentrations of Salmonella bacteria. This system allows a rapid and automatic endpoint detection which could lead to the development of a point-of-care diagnosis device for foodborne pathogens detection in a resource-limited environment.
  • Publication
    Effective synthesis of silicon carbide nanotubes by microwave heating of blended silicon dioxide and multi-walled carbon nanotube
    Silicon carbide nanotube (SiCNTs) has been proven as a suitable material for wide applications in high power, elevated temperature and harsh environment. For the first time, we reported in this article an effective synthesis of SiCNTs by microwave heating of SiO2 and MWCNTs in molar ratio of 1:1, 1:3, 1:5 and 1:7. Blend of SiO2 and MWCNTs in the molar ratio of 1:3 was proven to be the most suitable for the high yield synthesis of β-SiCNTs as confirmed by X-ray diffraction pattern. Only SiCNTs were observed from the blend of MWCNTs and SiO2 in the molar ratio of 1:3 from field emission scanning electron microscopy imaging. High magnification transmission electron microscopy showed that tubular structure of MWCNT was preserved with the inter-planar spacing of 0.25 nm. Absorption bands of Si-C bond were detected at 803 cm-1 in Fourier transform infrared spectrum. Thermal gravimetric analysis revealed that SiCNTs from ratio of 1:3 showed the lowest weight loss. Thus, our synthetic process indicates high yield conversion of SiO2 and MWCNTs to SiCNTs was achieved for blend of SiO2 and MWCNTs in molar ratio of 1:3.
  • Publication
    Morphological, structural, and electrical characterization of sol-gel-synthesized ZnO nanorods
    ( 2013-02-03)
    M. Kashif
    ;
    ;
    M. E. Ali
    ;
    ;
    Syed M. Usman Ali
    ZnO nanorods were grown on thermally oxidized p-type silicon substrate using sol-gel method. The SEM image revealed high-density, well-aligned, and perpendicular ZnO nanorods on the oxidized silicon substrate. The XRD profile confirmed thec-axis orientation of the nanorods. PL measurements showed the synthesized ZnO nanorods have strong ultraviolet (UV) emission. The electrical characterization was performed using interdigitated silver electrodes to investigate the stability in the current flow of the fabricated device under different ultraviolet (UV) exposure times. It was notified that a stable current flow was observed after 60 min of UV exposure. The determination of stable current flow after UV exposure is necessary for UV-based gas sensing and optoelectronic devices.