水溶性碳纳米粒子的制备及其在DNA和单核苷酸多态性分析中的应用

Preparation of water-soluble carbon nanoparticles and its applications for analysis of DNA and single nucleotide polymorphisms

利用电化学氧化的方法制备了水溶性好、粒径为7～12nm的碳纳米粒子,该碳纳米粒子通过π-π相互作用吸附荧光标记的单链DNA探针,并能有效地猝灭其荧光.当单链DNA探针与匹配的DNA目标分子杂交形成双链DNA时,猝灭的荧光被恢复,由此可以检测1～200nmol/L的DNA目标分子.此外,在碳纳米粒子存在时,由荧光标记的DNA探针和DNA目标分子形成的双链DNA的熔解温度可以简便地被测定,当双链DNA有错配碱基时,其熔解温度降低,由此可方便、快速地分析单核苷酸多态性.

Water-soluble carbon nanoparticles （CNPs） with a diameter of 7-12 nm were prepared with electrochemical oxidation. The CNPs exhibit high efficiency to quench the fluorescence of fluorescently labeled ssDNA probes by adsorbing the ssDNA on the CNPs surface through π-π interaction. The fluorescence can be recovered by addition of target DNA complementary to the ssDNA probe through hybridization to form double-strand DNA （dsDNA）. Therefore, the CNPs offer an effective analysis platform for detection of DNA, in which 1-200 nmol/L target DNA can be detected. Moreover, in the presence of CNPs, the melting temperature （Tm） of dsDNA containing fluorescently labeled ssDNA and DNA target can be determined, when the dsDNA contains mismatched bases, the Tm decreases. Based on the differentiation Tm values, the CNPs-based assay can be conveniently applied to analyze single nucleotide polymorphisms rapidly.