Mr. Meng-Houit Taing Profile

Meng-Houit Taing

at Griffith Univ

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Publications (4)

Proceedings Article | 19 January 2006 Paper

Microfabricated EIS biosensor for detection of DNA

M. Taing, D. Sweatman

Proceedings Volume 6036, 60361Q (2006) https://doi.org/10.1117/12.638652

KEYWORDS: Silicon, Sensors, Capacitance, Silica, Oxides, Capacitors, Electrodes, Biosensors, Signal processing, Microfabrication

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This paper focuses on the design of an EIS (electrolyte on insulator on Silicon) structure as a detection method for pathogenic DNA. Current rapid detection methods rely on fluorescent labeling to determine binding affinity. Fluorescent quenching is seen by a change in activity as opposed to non-quenched states. Sensitive optical equipment is required to detect and distinguish these colour changes because they cannot be seen by the naked eye. The disadvantages of this is (1) a portable, independent device cannot be made since samples have to be brought back to the benchtop and (2) the obvious cost of acquiring and maintaining these optical detection systems. A low cost, portable electrical detection method has been investigated. The EIS structure (Electrolyte on Insulator on Silicon) provides a novel, label-free and simple to fabricate way to make a small field effect DNA detection sensor. The sensor responds to fluctuating capacitances caused by a depletion layer thickness change at the surface of the silicon substrate as a result of DNA adsorption onto the dielectric oxide/APTES (Aminopropylthioxysilane) surface. As DNA molecules diffuse to the sensor surface, they are bound to their complimentary capture probes. The negative charge exhibited by the DNA forces negative charge carriers in the silicon substrate to move away from the surface. This causes a depletion layer in n-type substrate to thicken and for a p-type to thin and can be observed as a change in capacitance. A low ionic solution strength will ensure that counter-ions do not affect the sensor measurements. The EIS sensor is designed to be later integrated into a complete lab on chip solution. A full lab on chip can incorporate the sensor to perform DNA quantity based measurements. Nucleic acids can be amplified by the on chip PCR system and then fed into the sensor to work out the DNA concentration. The sensor surface contains capture probes that will bind to the pathogen. They are held onto the sensor surface by the positively charged layer. The sensor will have onboard electronics to process the signals and determine the result of the measurements. The sensitivity of the sensor is on par with similar capacitance sensing technologies and is expected to be improved with later enhancements.

Proceedings Article | 16 February 2005 Paper

Field effect sensors for biosensing

M. Taing, Denis Sweatman

Proceedings Volume 5651, (2005) https://doi.org/10.1117/12.582387

KEYWORDS: Silicon, Capacitance, Oxides, Sensors, Silica, Capacitors, Ions, Electrodes, Biosensing, Microelectronics

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Proceedings Article | 29 March 2004 Paper

Field effect sensors for PCR applications

Meng-Houit Taing, Denis Sweatman

Proceedings Volume 5275, (2004) https://doi.org/10.1117/12.529843

KEYWORDS: Sensors, Silicon, Capacitance, Electrodes, Silica, Oxides, Ions, Capacitors, Pathogens, Platinum

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The use of field effect sensors for biological and chemical sensing is widely employed due to its ability to make detections based on charge and surface potential. Because proteins and DNA almost always carry a charge [1], silicon can be used to micro fabricate such a sensor. The EIS structure (Electrolyte on Insulator on Silicon) provides a novel, label-free and simple to fabricate way to make a field effect DNA detection sensor. The sensor responds to fluctuating capacitance caused by a depletion layer thickness change at the surface of the silicon substrate through DNA adsorption onto the dielectric oxide/PLL (Poly-L-Lysine) surface. As DNA molecules diffuse to the sensor surface, they are bound to their complimentary capture probes deposited on the surface. The negative charge exhibited by the DNA forces negative charge carriers in the substrate to move away from the surface. This causes an n-type depletion layer substrate to thicken and a p-type to thin. The depletion layer thickness can be measured by its capacitance using an LCR meter. This experiment is conducted using the ConVolt (constant voltage) approach. Nucleic acids are amplified by an on chip PCR (Polymerase Chain Reaction) system and then fed into the sensor. The low ionic solution strength will ensure that counter-ions do not affect the sensor measurements. The sensor surface contains capture probes that bind to the pathogen. The types of pathogens we’ll be detecting include salmonella, campylobacter and E.Coli DNA. They are held onto the sensor surface by the positively charged Poly-L-Lysine layer. The electrolyte is biased through a pseudo-reference electrode. Pseudo reference electrodes are usually made from metals such as Platinum or Silver. The problem associated with “floating” biasing electrodes is they cannot provide stable biasing potentials [2]. They drift due to surface charging effects and trapped charges on the surface. To eliminate this, a differential system consisting of 2 sensors that share a common pseudo-reference electrode is used to cancel out this effect. This paper will look at a differential system for multi-arrayed biosensors fabricated on silicon.

Proceedings Article | 3 May 1999 Paper

Dye terminator chemistry: effects of substrate structure on sequencing analysis

Shaheer Khan, Barnett Rosenblum, Weiguo Zhen, Meng Taing, Steve Menchen

Proceedings Volume 3602, (1999) https://doi.org/10.1117/12.347536

KEYWORDS: Rhodamine, Chemistry, Dysprosium, Chemical elements, Polymers, Prisms, Energy transfer, Genetics, Biological research, Argon ion lasers

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