Department of Chemistry, Capital Normal University, Beijing, 100048, China.
Department of Chemistry, Capital Normal University, Beijing, 100048, China.
Talanta. 2021 Dec 1;235:122736. doi: 10.1016/j.talanta.2021.122736. Epub 2021 Jul 24.
Methods to improve the sensitivity of electrochemical sensors based on catalytic reactions generally require adscititious or pre-modified catalysts, which make the sensitive detection of sensors extremely challenging. This is because the activity of the catalyst is susceptible to the storage and modification process, such as aggregation during storage or loss of active sites during multi-step modification, which impairs the performance of the sensor. To solve this thorny issue, a novel electrochemical sensor based on a process-formed laccase-like catalyst was constructed for sensitive detection of tumor markers. Cu-polydopamine (CuPDA) combined with antibody (Ab) were employed as copper-containing immunoprobe, which released Cu(Ⅱ) ions under acidic stimulation. Cu(Ⅱ) ions coordinate with the self-assembly cationic diphenylalanine-glutaraldehyde nanospheres (CDPGA) to form a laccase-like catalyst, which had stronger catalytic activity than laccase. The freshly formed catalyst was immediately used to degrade the polyhydroquinone-reduced graphene oxide (PHQ-rGO) composite, resulting in a significant reduction in the current signal. The PHQ-rGO composite plays dual roles of signal substance and substrate on the sensing interface. The proposed electrochemical sensor demonstrated wide linearity for the determination of a model analyte, human epididymis protein 4 (HE4), from 1 pg mL to 100 ng mL, and the detection limit was as low as 0.302 pg mL (S/N = 3), which had good consistency with that of electrochemiluminescence method. This process-formed catalyst approach will have potential reference significance for the construction of other sensors.
基于催化反应提高电化学传感器灵敏度的方法通常需要外加或预修饰的催化剂，这使得传感器的灵敏检测极具挑战性。这是因为催化剂的活性容易受到储存和修饰过程的影响，例如储存过程中的聚集或多步修饰过程中活性位点的损失，这会损害传感器的性能。为了解决这个棘手的问题，构建了一种基于过程形成的漆酶样催化剂的新型电化学传感器，用于灵敏检测肿瘤标志物。Cu-聚多巴胺（CuPDA）与抗体（Ab）结合作为含铜免疫探针，在酸性刺激下释放 Cu(Ⅱ)离子。Cu(Ⅱ)离子与自组装的阳离子二苯丙氨酸-戊二醛纳米球（CDPGA）配位形成漆酶样催化剂，其催化活性比漆酶更强。新形成的催化剂立即用于降解聚对苯二酚还原氧化石墨烯（PHQ-rGO）复合材料，导致电流信号显著降低。PHQ-rGO 复合材料在传感界面上同时发挥信号物质和底物的双重作用。所提出的电化学传感器对模型分析物人附睾蛋白 4（HE4）的测定表现出很宽的线性范围，从 1 pg mL 到 100 ng mL，检测限低至 0.302 pg mL（S/N = 3），与电化学发光法具有良好的一致性。这种过程形成的催化剂方法将对其他传感器的构建具有潜在的参考意义。
