Construction And Experimental Study Of The Electrochemical DNA Biosensor Base On The Nano-particles Of Gold And Chitosan

In the recent years, the electrochemical DNA biosensors have been rapidly developed to be a firenew biological sensor. The electrochemical DNA biosensors have received much attention due to the high sensitivity, specific, rapid response, easy handling and low cost. Since many of the properties that biosensors are supposed to measure and formed on the molecular level. Because of their special structural feature and theirs unique electronic and mechanical properties, combine in a unique way to show high electrical conductivity, high chemical stability, extremely high mechanical strength and modulus, Nanoparticles have attracted increasing attention by scientists all over the world. The electrochemical DNA biosensors constructed at the molecular scale would be extremely sensitive, selective, and responsive. Thus, the potential application value of nanoparticle on biosensors is very huge.With the good characteristic of the nano gold and the excellent biocompatibility of the Chitosan, nano Au/CS composite was first prepared in this dissertation, and characterized by the TEM, UV/Vis and electrochemical methods. The nano composite materials of Au/CS show excellent stability and disperse uniformity. And the DNA electrochemical biosensor was prepared based on the Au/CS nanoparticles assembled on the GCE. This biosensor was used to determine the concentration of complementary sequences of the CML and the APL while the detecting process,the effect of intercalation time,intercalation concentration,hybridization solution to the detection result was discussed. The stability and the specificity of the nano DNA biosensor were also been investigated.The nano DNA biosensor was constructed by the Au/CS nanoparticles and applied to the detection of short DNA of the specific gene of CML and APL using the MB hybridization as electrochemical indicator. Under the optimal condition of the hybridization, While detecting the complementary DNA standard concentration range of the BCR/ABL and the PML-RARαfrom 1.0×10-8 to 8.0×10–7 mol/L and 1.0×10-8 to 1.0×10–6 mol/L, respectively, there was a good linear relationship between the respond signal of electrochemical indicator and the concentration of complementary DNA, the lower limit is 5.0×10-10 mol/L. And in order to explore the stability and the specificity of the nano DNA biosensor base on the Au/CS composite nanoparticles. We use the Isorhamnetin (ISO) as a new electrochemical hybridization indicator. The nano DNA biosensors show satisfactary reproducibility and specificity. The detection methods of BCR/ABL genes of the CML and the PML-RARαfusion gene of APL were established by novel nano DNA sensor based on the Au/CS composite nanoparticles. And the foundation investigation was provided for clinical application to diagnose and monitor of the CML and the APL patients.