The fabrication of electrochemical biosensors to directly, rapidly and ultrasensitively detect disease markers in urine or blood samples has become a new and competitive challenge in the field of sensor research. In this paper, a novel electrochemical immunosensor with high selectivity and sensitivity for the detection of the depression marker human apolipoprotein A4 (Apo-A4) was successfully constructed using zeolite imidazole ester metal organic skeleton-nitrogen doped graphene composites (ZIF-8@N-Gr). To this end, because of the higher surface area and biocompatibility, ZIF-8 with abundant biomolecular binding sites provided a good microenvironment for effectively immobilizing antigens. ZIF-8@N-Gr presented a flake structure, as the electrode displayed excellent electrical conductivity, which enhanced the electron transfer and significantly amplified the current signal of the immunosensor. More importantly, these immunosensors are capable of assaying human apolipoprotein A4 (Apo-A4) in 100% serum without suffering from any significant biological interference. Under optimized experimental conditions, the sensor was used for the analysis of whole serum samples and presented a wide linear range from 1.47 × 10⁻¹⁰ g/mL to 3.00 × 10⁻⁷ g/mL with a low detection limit of 8.33 × 10⁻¹¹ g/mL (3σ, n = 15). The satisfactory results of human serum sample analysis indicated that the proposed immunosensor had promising potential in the clinical diagnosis of depression.

直接，快速和超灵敏地检测尿液或血液样品中疾病标记的电化学生物传感器的制造已成为传感器研究领域中的一项新的竞争性挑战。本文成功地利用沸石咪唑酯金属有机骨架氮掺杂石墨烯复合材料（ZIF-8 @ N-）成功构建了一种新型的具有高选择性和灵敏度的电化学免疫传感器，用于检测抑郁症标记人载脂蛋白A4（Apo-A4）。 Gr）。为此，由于具有较高的表面积和生物相容性，具有丰富的生物分子结合位点的ZIF-8为有效地固定抗原提供了良好的微环境。ZIF-8 @ N-Gr呈片状结构，因为电极显示出优异的导电性，从而增强了电子传递并大大放大了免疫传感器的电流信号。更重要的是，这些免疫传感器能够测定100％血清中的人类载脂蛋白A4（Apo-A4），而不会遭受任何重大的生物学干扰。在优化的实验条件下，该传感器用于分析全血清样品，并具有1.47×10的宽线性范围^-10 g / mL至3.00×10 ^-7 g / mL，检测限低至8.33×10 ^-11 g / mL（3σ，n = 15）。人类血清样品分析的令人满意的结果表明，所提出的免疫传感器在抑郁症的临床诊断中具有广阔的前景。