微囊藻属DNA电化学传感器的研制

利用自组装法将巯基修饰的DNA探针与6-巯基-1-己醇(MCH)固定到金电极表面,制备了微囊藻属特定DNA传感器,将该传感器与完全互补的微囊藻DNA序列、完全不互补序列,以及单碱基错配序列进行杂交,以Hoechst 33258为杂交指示剂,应用循环伏安法和线性扫描伏安法研究了该传感器对目标DNA的电化学检测行为.研究表明,当与完全互补DNA杂交后,Hoechst 33258氧化信号有明显的增强.实验对自组装时间、MCH浸泡时间及杂交液离子浓度进行了优化.结果表明,当自组装时间为90 min,MCH浸泡时间为1 h,杂交溶液中NaCl浓度为0.3 mol/L时,电化学信号最好.目标DNA的氧化峰电流值与其浓度在1×10~(-8) ～1×10~(-6) mol/L范围内呈良好的线性关系,检出限为8.1×10~(-9) mol/L.

Electrochemical DNA Sensor for Microcystis Detection

An electrochemical DNA sensor was designed to detect DNA specific-sequences of micro-cystis immobilizing a single-stranded 18mer oligonucleotide (ssDNA) onto a gold disk electrode by self-assembling and using 6-mercapto-l-hexanol( MCH) as spacer. The ssDNA could undergo hybridization in a solution containing complementary or non-complementary or single base pair mismatches DNA sequences of microcystis, respectively. DNA immobilization and hybridization were characterized by cyclic voltammetry ( CV ) and linear sweep voltammetry( LSV) using Hoechst 33258 as indica-tor. A significant increase of the peak current for Hoechst 33258 was observed after the hybridization of immobilized ssDNA with complementary DNA in the solution. Based on this, a method was estab-lished to recognize microcystis DNA sequence. The experimental parameters, such as self-assembling time, exposing time to MCH and salt concentration of hybridization buffer solution were optimized. The results indicated that the best electrochemical response could be obtained by using 90 min self-as-sembling time and 1 h exposing time to MCH in hybridization solution containing 0. 3 mol/L NaCl. A good linear relationship between microcystis DNA sequence concentration and electrochemical signal was found in the range of 1 × 10~(-8) -1 × 10~(-6) mol/L with a detection limit of 8. 1 × 10~(-9) mol/L.