基于石墨相氮化碳-富勒烯构建光电化学生物传感器

A photoelectrochemical biosensor based on g-graphite carbon nitride-fullerene

该工作基于石墨相氮化碳-富勒烯(g-C_(3)N_(4)-C_(60)),构建了“信号关”型光电化学(PEC)生物传感器,实现了对铅离子(Pb^(2+))的灵敏检测。首先,在玻碳电极(GCE)表面修饰光电材料g-C_(3)N_(4)-C_(60),由于其良好的光电性能,可以观察到较好的初始PEC信号。然后,在修饰了g-C_(3)N_(4)-C_(60)的电极上电沉积一层金纳米粒子(Dep Au),随后将带有巯基的DNA通过Au-S键固载在电极表面。紧接着用1-己硫醇(HT)封闭电极表面的非特异性吸附位点。最终,在Pb^(2+)存在的情况下,Pb^(2+)会与富含鸟嘌呤(G)的DNA结合,使其折叠形成G-四链体结构,从而获得显著降低的PEC信号。通过记录PEC信号的变化实现对目标物Pb^(2+)的灵敏检测。结果表明,光电流与Pb^(2+)浓度的对数呈现良好的线性关系,其线性范围为50.0 pmol/L-50.0μmol/L,检测限为16.60 pmol/L。

A sensitive"signal off"mode photoelectrochemical(PEC)biosensor for sensitive detection of lead ions(Pb^(2+))was constructed based on g-graphite carbon nitride-fullerene(g-C_(3)N_(4)-C_(60)).Firstly,g-C_(3)N_(4)-C_(60) was modified on glassy carbon electrode(GCE)surface.Because of its good photoelectric properties,a good initial PEC signal can be observed.Then,gold nanoparticles were electrodeposited(Dep Au),and then DNA with sulfhydryl groups was immobilized through Au-S bond.Then,1-hexanethiol(HT)was used to block nonspecific adsorption sites.Finally,in the presence of Pb^(2+),it would combine with rich-G DNA and form G-quadruple structure,thus obtaining a significantly reduced PEC signal.Sensitive detection of Pb^(2+)was realized by recording the change of PEC signal.The results showed that PEC signal towards the logarithm of Pb^(2+)concentration presented a good linear relationship with the linear range of 50.0 pmol/L-50.0μmol/L and the detection limit of 16.60 pmol/L.