Research Publications

Articles in Academic Journals

2017

Authors: Abkar Ahmed Sayad, Fatimah Ibrahim, Shah Mukim Uddin, Jongman Cho, Marc Madou, Kwai Lin Thong

Publisher: Elsevier | Journal: Biosensors and Bioelectronics

Published: 31 August 2017

doi: 10.1016/j.bios.2017.08.060

Abstract: Outbreaks of foodborne diseases have become a global health concern; hence, many improvements and developments have been made to reduce the risk of food contamination. We developed a centrifugal microfluidic automatic wireless endpoint detection system integrated with loop mediated isothermal amplification (LAMP) for monoplex pathogen detection. Six identical sets were designed on the microfluidic compact disc (CD) to perform 30 genetic analyses of three different species of foodborne pathogens. The consecutive loading, mixing, and aliquoting of the LAMP primers/reagents and DNA sample solutions were accomplished using an optimized square-wave microchannel, metering chambers and revulsion per minute (RPM) control. We tested 24 strains of pathogenic bacteria (Escherichia coli, Salmonella spp and Vibrio cholerae), with 8 strains of each bacterium, and performed DNA amplification on the microfluidic CD for 60 min. Then, the amplicons of the LAMP reaction were detected using the calcein colorimetric method and further analysed via the developed electronic system interfaced with Bluetooth wireless technology to transmit the results to a smartphone. The system showed a limit of detection (LOD) of 3 × 10−5 ng μL−1 DNA by analysing the colour change when tested with chicken meat spiked with the three pathogenic bacteria. Since the entire process was performed in a fully automated way and was easy to use, our microdevice is suitable for point-of-care (POC) testing with high simplicity, providing affordability and accessibility even to poor, resource-limited settings.

2016

Authors: Abkar Ahmed Sayad, Fatimah Ibrahim, Shah Mukim Uddin, Koh Xiu Pei, Mas S. Mohktar, Marc Madou, Kwai Lin Thong

Publisher: Elsevier | Journal: Sensors and Actuators B: Chemical

Published: 4 January 2016

doi: 10.1016/j.snb.2015.10.116

Abstract: Salmonellosis is one of the most common foodborne diseases caused by the genus Salmonella and is considered to be a significant global health concern. Therefore, the development of effective techniques for rapidly detecting Salmonella is fundamental in preventing foodborne outbreaks. This paper presents a lab-on-a-disc integrated loop mediated isothermal amplification (LAMP) on a microfluidic platform for Salmonella detection. We have developed a centrifugal microfluidic platform device in which the main steps in pathogen detection, reagent preparation, LAMP, and detection can be integrated onto a single microfluidic compact disc (CD). A forced convection heating source was used for wax valve actuation and temperature heating for the LAMP amplification, leading toward compactness and system miniaturization. The detection limit was 5 × 10−3 ng/μL DNA concentration when tested on tomatoes spiked with Salmonella. The whole procedure, from sample preparation (on the microfluidic CD) up to detection, was completed within 70 min using a fully automated process. The final detection step was performed via direct visual observation of the color change of the SYBR Green I dye. Our system offers a fast and automated molecular diagnostic platform, thereby reducing the need for skillful operators and expensive instrumentation. This developed portable device would have a wide range of potential biomedical applications, including foodborne pathogen detection and molecular diagnostics in developing countries.microfluidic CD) up to detection, was completed within 70 min using a fully automated process. The final detection step was performed via direct visual observation of the color change of the SYBR Green I dye. Our system offers a fast and automated molecular diagnostic platform, thereby reducing the need for skillful operators and expensive instrumentation. This developed portable device would have a wide range of potential biomedical applications, including foodborne pathogen detection and molecular diagnostics in developing countries.

https://sites.google.com/site/shahmukim/publication/Lab-on-a-Disc.JPG?attredirects=0

2015

Authors: Samira Hosseini, Mohammad M. Aeinehvand, Shah Mukim Uddin, Abderazak Benzina, Hussin A. Rothan, Rohana Yusof, Leo H. Koole, Marc J. Madou, Ivan Djordjevic & Fatimah Ibrahim

Publisher: Nature Publishing Group | Journal: Scientific Reports

Published: 09 November 2015

doi: 10.1038/srep16485

Abstract: The application of microfluidic devices in diagnostic systems is well-established in contemporary research. Large specific surface area of microspheres, on the other hand, has secured an important position for their use in bioanalytical assays. Herein, we report a combination of microspheres and microfluidic disk in a unique hybrid platform for highly sensitive and selective detection of dengue virus. Surface engineered polymethacrylate microspheres with carefully designed functional groups facilitate biorecognition in a multitude manner. In order to maximize the utility of the microspheres’ specific surface area in biomolecular interaction, the microfluidic disk was equipped with a micromixing system. The mixing mechanism (microballoon mixing) enhances the number of molecular encounters between spheres and target analyte by accessing the entire sample volume more effectively, which subsequently results in signal amplification. Significant reduction of incubation time along with considerable lower detection limits were the prime motivations for the integration of microspheres inside the microfluidic disk. Lengthy incubations of routine analytical assays were reduced from 2 hours to 5 minutes while developed system successfully detected a few units of dengue virus. Obtained results make this hybrid microsphere-microfluidic approach to dengue detection a promising avenue for early detection of this fatal illness.

Authors: Shah Mukim Uddin, Fatimah Ibrahim, Abkar Ahmed Sayad, Aung Thiha, Koh Xiu Pei, Mas S. Mohktar, Uda Hashim, Jongman Cho and Kwai Lin Thong

Publisher: MDPI | Journal: Sensors

Published: 5 March 2015

doi: 10.3390/s150305376

Abstract: 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.

Proceedings

2015

Optimization of the Amplicons Detection System of Loop-mediated Isothermal Amplification on Microfluidic Compact Disk

Authors: Shah Mukim Uddin, Fatimah Ibrahim, Jongman Cho, and Kwai Lin Thong

Publisher: IEEE

International Conference on Biomedical and Health Informatics 2015, Haikou, China