A sensitive label-free electrochemical immunosensor was designed using a novel signal amplification system for quantitative detecting hepatitis B surface antigen (HBsAg). Nitrogen-doped graphene quantum dots (N-GQDs) supported surfactant-free AuPdCu ternary nanoparticles (AuPdCu/N-GQDs), which featured with good conductivity and excellent catalytic properties for the reduction of hydrogen peroxide (H₂O₂), was synthesized by a simple and benign hydrothermal procedure. At the same time, the electroactive polymer nanospheres (PS) was synthesized by infinite coordination polymers of ferrocenedicarboxylic acid, which could play as carrier and electronic mediator to load AuPdCu/N-GQDs. The PS not only improved the ability to load antibodies because of the good biocompatibility, but also accelerated electron transport of the electrode interface attribute to plentiful ferrocene unit. Thus, the prepared AuPdCu/[email protected] has abilities of good biocompatibility, catalytic activity and electrical conductivity to be applied as transducing materials to amplify electrochemical signal in detection of HBsAg. Under optimal conditions, the fabricated immunosensor exhibited high sensitivity and stability in the detection of HBsAg. A linear relationship between current signals and the concentrations of HBsAg was obtained in the range from 10 fg/mL to 50 ng/mL and the detection limit of HBsAg was 3.3 fg/mL (signal-to-noise ratio of 3). Moreover, the designed immunosensor with excellent selectivity, reproducibility and stability shows excellent performance in detection of human serum samples. Furthermore, this label-free electrochemical immunosensor has promising application in clinical diagnosis of HBsAg.

使用新型信号放大系统设计了灵敏的无标记电化学免疫传感器，用于定量检测乙型肝炎表面抗原（HBsAg）。氮掺杂石墨烯量子点（N-GQDs）负载无表面活性剂的AuPdCu三元纳米颗粒（AuPdCu / N-GQDs），具有良好的电导率和出色的催化性能，可减少过氧化氢（H ₂ O _2））是通过简单而良性的水热程序合成的。同时，通过二茂铁二羧酸的无限配位聚合物合成了电活性聚合物纳米球（PS），可以作为载体和电子介质负载AuPdCu / N-GQDs。PS不仅由于具有良好的生物相容性而提高了加载抗体的能力，而且由于大量的二茂铁单元而加速了电极界面的电子传输。因此，所制备的AuPdCu / [电子邮件保护的]具有良好的生物相容性，催化活性和导电性的能力，可被用作转导材料以放大检测HBsAg的电化学信号。在最佳条件下，所制备的免疫传感器在检测HBsAg方面显示出高灵敏度和稳定性。电流信号与HBsAg浓度之间的线性关系在10 fg / mL至50 ng / mL的范围内，HBsAg的检出限为3.3 fg / mL（信噪比为3）。而且，所设计的具有优异的选择性，可重复性和稳定性的免疫传感器在检测人血清样品中显示出优异的性能。此外，这种无标记的电化学免疫传感器在HBsAg的临床诊断中具有广阔的应用前景。