【摘要】 研究了DNA夹心杂交和直接杂交体系,将功能化纳米金引入到标记有生物素的杂交双链上,制成具有电化学活性和纳米金放大作用的DNA电化学传感器,采用循环伏安法测试.在夹心杂交体系中,靶点DNA浓度与阳极峰电流关系曲线的相对标准偏差为3.0%～13.0%,在浓度为6.9×10-3～0.14nmol/L范围内得到良好的线性关系,检测限达到2.0×10-3nmol/L,实现了对单碱基突变的高灵敏检测和序列识别.直接杂交检测限为2.5×10-4mol/L,分别在2.5×10-4～5.0×10-3nmol/L和5.0×10-3～10nmol/L范围内得到峰电量与浓度的良好线性关系.并比较这两种体系.更多还原

【Abstract】 Ferrocene(Fc)-capped gold nanoparticle/streptavidin conjugates were attached onto the electrodes covered with either biotinylated or sandwich oligodeoxynucleotides(ODNs) duplexes. The binding events were monitored by electrochemical signal of ferrocene. The signal differences permitted to distinguish the match of two perfectly complementary DNA strands from the near-perfect match where just one base pair was mutant. The effects of the DNA probe and target strand lengths on the voltammetric behavior of the Fc groups were studied. It was found that shorter duplexes would lead to a more reversible voltammetric wave and a higher detection level. For the analysis of 30-mer biotinylated target DNA, a concentration level as low as 2.5×10{-4} nmol/L could be detected while for 39-mer target of sandwich duplexes, the limit of detection was 2.0×10{-3} nmol/L. The capabilities of the method for trace analysis of DNA can be attributed to the enhanced voltammetric detection by the large number of Fc moieties present in each conjugate.更多还原