中文摘要：

利用铁氰化钴/树状高分子（CoHCF/PAMAM）复合材料修饰玻碳电极（GCE）, 制备了免标记检测基因突变的新型DNA电化学传感器. 传感器中树状高分子层明显增加了单链DNA探针的固定量, 铁氰化钴层增大了鸟嘌呤的氧化信号, 该传感器可以灵敏识别单碱基错配的基因序列, 具有良好的选择性和灵敏度. 在7.6×10-11～3.05×10-8 mol/L浓度范围内, 鸟嘌呤（G）的氧化峰电流差值与突变基因浓度呈良好的线性关系, 检出限为1.0×10-11 mol/L（S/N=3）.

英文摘要：

Electrochemical hybridization biosensor for label-free determination of sequence-specific DNA was described. First, cobalt hexacyanoferrate films and poly （amidoamine）（PAMAM） dendrimer（generation 4.0） were modified on the glassy carbon electrode（GCE） sequentially. Then, DNA probes were successfully immobilized on the modified electrode with G4 PAMAM dendrimer acting as the coupling agent. The hybridization events were monitored by differential pulse voltammetry（DPV） measurement based on the oxidation signals of guanine without any external labels. This biosensor exhibited a superior electrochemical stability, selectivity and sensitivity in detection of the oligonucleotide sequence. Under the optimal conditions, the guanine oxidation signal was directly proportional to the mutant gene sequence concentration from 7.6×10-11 to 3.05×10-8 mol/L with a correlation coefficient of 0.9975 and a detection limit of 1.0×10-11 mol/L（S/N=3）.