Generally, H₂O₂ is frequently adopted to improve analysis capabilities of various detection systems. However, the addition of H₂O₂ with relatively higher concentration can lower the bioactivity of antibodies or antigens and the sensing interface stability in most peroxidase and peroxidase-like immunosensors. In order to solve these issues, we designed a novel copper peroxide/ZIF-8 immunoprobe that can self-produce H₂O₂ to trigger a cascade reaction for the sensitive detection of carbohydrate antigen 19–9. Specifically, CP/ZIF-8 plays a key role as a “signal switch” in the immunosensor. In the presence of HCl, the structures of ZIF-8 and copper peroxide can be broken, producing Cu²⁺ and H₂O₂ and a subsequent Fenton-type reaction that generates •OH. The resulting •OH can induce the decomposition of 3-aminobenzeneboronic acid/poly (vinyl alcohol) (PVA) film on the electrode. Although the immunosensor initially showed little current signal due to the poor conductivity pf ZIF-8 and PVA, the current signal was significantly amplified by a HCl-triggered cascade reaction. Under optimal conditions, the immunosensor displayed a wide linear range from 0.0001 to 100 U mL⁻¹ with an ultralow limit of detection of 53.5 μU mL⁻¹ (S/N = 3) for carbohydrate antigen 19–9. Considering these advantages, namely self-producing H₂O₂ and easy operation, this strategy paves a new way to design other novel sensors.

通常，经常采用H ₂ O ₂来提高各种检测系统的分析能力。但是，添加相对较高浓度的H ₂ O ₂会降低抗体或抗原的生物活性，并降低大多数过氧化物酶和过氧化物酶样免疫传感器的传感界面稳定性。为了解决这些问题，我们设计了一种新型的过氧化铜/ ZIF-8免疫探针，该探针可以自行产生H ₂ O _2，以触​​发级联反应，从而灵敏地检测19–9糖类抗原。具体而言，CP / ZIF-8在免疫传感器中扮演着“信号开关”的关键角色。在HCl的存在下，ZIF-8和过氧化铜的结构会被破坏，从而生成铜²⁺和H ₂ O ₂以及随后的生成•OH的Fenton型反应。生成的•OH可以引起电极上3-氨基苯硼酸/聚乙烯醇（PVA）膜的分解。尽管由于ZIF-8和PVA的导电性差，免疫传感器最初显示的电流信号很小，但是通过HCl触发的级联反应，电流信号得到了显着放大。在最佳条件下，免疫传感器显示从0.0001到100 U mL ^-1的宽线性范围，对19–9类碳水化合物抗原的检测极限为53.5μUmL ^-1（S / N = 3）。考虑到这些优势，即自产H ₂ O ₂ 且操作简便，此策略为设计其他新颖的传感器铺平了道路。