| Electrochemical biosensor combines the potent function of electrochemical electro-analysis and the process of biological specialty identification, transforming biological identification signal into electrical signal and outputting them by the ways of electrical current, potential, electrical quantity, conductance, etc. This paper takes electrochemical biosensor as matrix, prepares single-channel screen printing golden electrode, and researches the surface nature of the electrode, discusses the modification method and mechanism of the electrode, and on that basis prepares dual-channel electrode and develops two kinds of DNA electrochemical biosensor to detect the DNA specific sequence.Electrochemical DNA biosensor was prepared based on Single-channel screen printing golden electrode. Thiolated DNA probe is fixed to the surface of screen printing golden electrode by self-assembly. Cyclic voltammetry and differential pulse voltammetry are used to study the electrochemical test of biosensor on DNA specific sequence. This paper discusses self-assembly density, MB concentration, salt ion concentration in hybrid solution and other parameters affecting the hybrid experiment. The results show that this sensor has a good performance in selecting the DNA specific sequence and an linear correlation between peak current value and concentration of target DNA specific sequence has been found within the 1×10-8-1×10-6 mol/L range, with the limit of detection being 2.7×10-9 mol/L.Single-channel testing system is transferred to the platform of electrochemical DNA biosensor of dual-channel screen printing golden electrode so as to test two different DNA specific sequences. Experiment conditions like the time for self-assembling, for exposure to MCH, for hybridization and for MB accumulation are optimized. The results show that dual-channel sensor has a good linear range between 1×10-8-1×10-6 mol/L.The limits of detection for the dual-channel biosensor were 2.1×10-9 mol/L and 5.5×10-9 mol/L, respectively. |
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