tailieunhanh - Electrochemical DNA sensor for label - free soybean transgenic detection

This paper describes the development of electrochemical label- free DNA sensor for detection of transgenic in Round–up Ready Soybean (herbicide tolerance). Two pairs of electrodes which the optimized dimension is 70µm x 30µm (the width of electrode x inter-distance between fingers), were fabricated on a chip for differential measures. | Journal of Chemistry Vol. 45 2 P. 241 - 244 2007 ELECTROCHEMICAL DNA SENSOR FOR LABEL - FREE SOYBEAN TRANSGENIC DETECTION Received 3 July 2006 PHUONG DINH TAM1 NGUyEN HAI BINH1 MAI ANH TUAN1 NGUyEN Duc CHIEN1 2 international Training Institute for Materials Science HUT 2Insitute of Engineering Physics HUT SUMMARy This paper describes the development of electrochemical label- free DNA sensor for detection of transgenic in Round-up Ready Soybean herbicide tolerance . Two pairs of electrodes which the optimized dimension is 70 x 30 the width of electrode x inter-distance between fingers were fabricated on a chip for differential measures. The DNA probe 35S 5 -GCT CCT ACA AAT GCC ATC A-3 was designed in such a way that it can hybridize with the CaMV 35S promoter of Roundup Ready soybean. The DNA was immobilized on the surface of the sensor by the mean of 3-aminopropyl triethoxysilane APTS polymer. The response time of DNA sensor is less than 1 second in case of 100 matching level the sensitivity is 2 mV uM. The activity of DNA sensor remains unchanged after 9 months of storage at -4oC in DI water. Some random soybean samples were collected extracted and tested by the DNA sensor and the results were well matched with the of PCR method. I - INTRODUCTION The detection of specific DNA RNA sequences is great important in numerous applications such as clinical diagnosis food safety pharmacogenetic criminology and many other fields 1 . DNA sensors are based on single-stranded oligonucleotide ODN probe designed DNA sequence immobilized on a physical substrate. The immobilization of tagged double stranded ODNs provides the basis of sample detection and the resulting pattern is detected by for example fluorescence chemiluminescance or from the tag 2 . The main drawbacks of such detection methods are cost complexity and inefficiency of tagging reactions. A number of alternative label-free methodologies have also been developed such as quartz crystal microbalance QCM 3 or