基于脱氧核酶的新型铅离子荧光探针

将荧光猝灭基团修饰的17E脱氧核酶(17E DNAzyme)与荧光基团修饰的底物链通过6个脱氧核苷酸相连, 得到了一种新型的对Pb2+敏感的荧光探针. 由于DNAzyme与底物链发生分子内杂交, 荧光基团与猝灭基团相互靠近, 导致荧光猝灭. 当Pb2+存在时, DNAzyme被激活, 底物链被切断后释放出荧光基团标记的DNA片段, 从而产生明显的荧光信号. 据此可在常温下快速检测Pb2+, 检测下限为10 nmol/L. 在Zn2+, Mn2+, Co2+, Cd2+, Cu2+, Mg2+和Ni2+等多种二价金属离子中, 除Zn2+, Mn2+和Cd2+略有干扰外, 其它几种金属离子均无响应, 表明该荧光探针对Pb2+具有良好的选择性.

Novel Fluorescent Probe for Lead Ion Detection Based on DNAzyme

A novel fluorescent probe for Pb2 was obtained,in which the quencher modified 17E DNAzyme and the fluorophore-modified substrate strand were connected through 6 adenine deoxynucleotides.Due to the intramolecular hybridization between 17E DNAzyme and the substrate strand,the quencher was closed to the fluorophore and it resulted in fluorescence quenching.In the presence of Pb2 ,the substrate strand was cleaved under the catalysis of enzyme strand,and the fluorophore-modified fragment was released,which resulted in the increase of fluorescence.Pb2 could be rapidly detected at room temperature based on this principle,and the limits of detection were 10 nmol/L.For divalent metal ions,such as Zn2 ,Mn2 ,Co2 ,Cd2 ,Cu2 ,Mg2 and Ni2 ,only Zn2 ,Mn2 and Cd2 showed a slight increase of fluorescence intensity while all the other metal ions gave approximately background intensity.It is demonstrated that the novel fluorescent probe has a good selectivity to Pb2 .