Novel portable electrical detection system for DNA SENSOR application

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 mM. 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.

Design of a Functional Signal Generator Based on MAX038 and Microcontroller

“…In the waveform frequency control circuit, STC89C52 SCM P32, P33, P35 control the SPI Serial DAC TLC5615, 10 serial clock input SCLK, serial data input DIN and TLC5615 chip select signal CS end [7]. After the analog voltage D/A conversion, it is output from 7 feet out TLC5615 via the resistor R1 = 50kΩ enter MAX038 pin 10 (IIN pin) on the frequency of the output waveform so that it can be controlled.…”