基于聚硫堇、DNA/纳米银复合物共修饰癌胚抗原免疫传感器的研究

Immunosensor Study for Carcinoembryonic Antigen Based on Poly-thione and (DNA/nano Ag) Composite

将硫堇聚合到玻碳电极(GCE)表面形成带正电的多孔聚硫堇(PTH)复合膜,通过静电吸附固定DNA/纳米银复合物,利用复合物中纳米银大的比表面积和强的吸附能力将癌胚抗体(anti-CEA)固定到电极表面,从而制得高灵敏的电流型癌胚抗原(CEA)免疫传感器.通过循环伏安法考察了电极表面的电化学行为,并对免疫传感器的性能进行了详细研究.在最优的实验条件下,用示差脉冲伏安法(DPV)对癌胚抗原进行检测,其线性范围为1.0～10.0ng·mL-1和10.0～80.0ng·mL-1,线性相关系数分别为0.9983和0.9970,检测限为0.24ng·mL-1,并将该免疫传感器用于血清样品中CEA的检测.

A novel amperometric immunosensor for the determination of carcinoembryonic antigen （CEA） based on DNA/nano Ag composite and poly-thione has been fabricated. The composite, which contains DNA （negatively charged） and nano Ag, can not only be immobilized to the glass carbon electrode surface modified with poly-thione （positively charged） through negatively charged DNA, but also adsorb carcinoembryonic antibodies through nano Ag particles with large specific surface areas and good biocompatibility. The modification procedure was electrochemically monitored by cyclic voltammetry. The performance and influencing factors of the resulting immunosensor were studied in detail. Under optimal conditions, the developed immunosensor exhibited fast response to CEA and the linear ranges were 1.0～10.0 and 10.0～ 80.0 ng·mL-1 with correlation coefficients of 0.9983 and 0.9970, respectively, and a detection limit of 0.24 ng·mL-1 （at 3σ）. Moreover, the precision, reproducibility and stability of the as-prepared immunosensor were acceptable. Importantly, the proposed methodology would be valuable for diagnosis and monitoring of carcinoma and its metastasis.