非标记型p53抑癌基因电化学DNA生物传感器的研究

Study on Label-free Electrochemical DNA Biosensor for p53 Tumor Suppressor Gene Detection

基于发夹型核酸探针的高特异性识别能力以及电活性物质与DNA磷酸骨架间的静电作用,以发夹型核酸作为分子识别探针,电活性物质六氨合钌（RuHex）作为杂交指示剂,构建了一种非标记型检测p53抑癌基因的电化学DNA生物传感器。实验结果表明,在10μmol/L RuHex溶液中,该传感器对目标DNA具有灵敏的电化学响应,电化学信号与目标DNA浓度在2.5~10 nmol/L范围内呈线性关系,检出限达2.5 nmol/L。根据电化学信号的差异可区别完全互补目标DNA、单碱基突变DNA和随机DNA分子。考察了单碱基突变位点不同的目标DNA分子与发夹型核酸探针的杂交效率,结果表明突变位点不同会影响发夹型核酸探针与目标DNA的杂交效率。该传感器具有选择性好、无需标记、简单等优点。

A label-free electrochemical biosensor was developed for the detection of p53 tumor suppressor gene using hairpin DNA as nucleic acid probe and RuHex as hybridization indicator,based on the specific recognition of hairpin DNA and the electrostatic interaction between[Ru（NH3）6]3＋ and DNA.The experimental results indicated that this electrochemical sensor can sensitively detect target DNA in 10 μmol/L RuHex solution with a detection limit of 2.5 nmol/L.According to the difference of the electrochemical signals,the sensor could discriminate the complete complementary DNA from single-mutation DNA and the random DNA.The hybridization efficiency of hairpin DNA and the target sequences with different mutation sites was investigated and the results showed that the mutate sites affected DNA hybridization efficiency.The prepared sensor showed the advantages of sensitivity,selectivity,label-free and simplicity.