石墨烯在金电极上固定方法的选择及免疫传感器的构建

Selection of immobilization methods of graphene on gold electrodes and fabrication of immunosensor

分别利用重氮化法、滴涂法、非共价键合法及偶联法将石墨烯固定于电极表面,并对所得到的修饰电极进行电化学表征,分析结果显示重氮化法制备的石墨烯修饰电极性能更稳定,信号更灵敏,所以将其用于免疫传感器的制备.首先在金电极上制备对氨基苯硫酚和苯硫酚的混合自组装单分子膜(MSAM),再利用重氮化法将石墨烯固定在MSAM修饰电极表面,然后在其表面电沉积纳米金,最后通过金-氨键固定抗体(羊抗小鼠IgG),并对小鼠IgG进行了初步检测,线性范围为0.001～400μg/L,检测下限达到0.0014μg/L.结果表明,该传感器具有检测范围宽、灵敏度高的优良性能,在临床检验中具有广阔的应用前景.

Graphene were immobilized on the surface of gold electrode by diazotization method, dip- ping method, non covalent bonding and coupling method, respectively. The obtained graphene-modi- fled electrodes were electrochemically characterized and the results showed the electrode prepared by diazotization method had more stable performance and sensitive signal. Thus, the diazotization meth- od was furthermore used for the fabrication of immunosensor based on graphene. Firstly the gold e- lectrode was modified with mix SAM of 4-amino thiolpheno （4-ATP） and thiolpheno （TP）, and then the graphenes were covalently anchored on electrode surfaces by the diazonium salt reactions with the end amino group of SAM. Secondly, after the nano Au were electrochemically depositing on the sur- face of electrode via the reduction of HAuC14, the sheep anti mouse immunoglobulin G （IgG） anti- bodies were conjugated with the nano Au through Au-NH2 bond. The obtained immunosensor could detect the mouse IgG in a range of 0.001-400μg/L with the detection limit of 0. 014 μg/L. The re- sults of experiments showed that the immunosensor based on graphene which was immobilized by di- azotization method had wide detection range, high sensitivity, so it will have a promising application in clinical detection.