posted Aug 11, 2012, 6:51 PM by Sensors VN
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updated Jul 11, 2013, 3:18 AM
]
By: Phuong Dinh Tam, Hoang Sy Hong, Nguyen Van Hieu.
 Abstract:
A novel, portable, electrical detection system was constructed for DNA
sensor application to detect DNA hybridisation. The read-out circuit
consists of an analogue circuit and a digital circuit. The analogue
circuit with an IC MAX038 generates a sine wave with a constant
frequency (10 kHz), which serves as the input for the DNA sensor. The
DNA sensor consists of active and reference sensors. DNA hybridisation
between the DNA probe and the target sequences causes changes in the
conductance of the conductive membrane (DNA/MWCNTs) on the sensor
surface, which lead to changes in the amplitude of the sine wave from
the sensor output compared with that of the reference signal output
(input sine wave). We used a digital circuit with a microprocessor
(PIC33FJ256MC710) to determine the change in the amplitude of the sine
wave signal of the sensor. From these digital data, the difference in
the amplitudes of the active and reference sensors was calculated and
displayed on the liquid crystal display. Measurement results show that
the portable electrical detection system can detect DNA target
concentrations as low as 0.16 µM. The detection of the amplified
polymerase chain reaction sample and the reproducibility of the DNA
sensor results were also determined using the designed readout circuit.
The proposed electrical detection system is suitable for DNA sensor
application. Full paper |
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