State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, People's Republic of China.
Mikrochim Acta. 2024 Jan 13;191(2):93. doi: 10.1007/s00604-023-06128-9.
A colorimetric strategy has been developed for the detection of alkaline phosphatase (ALP) activity based on the off-on effect of the catalytic activity of light-responsive oxidase mimics covalent organic framework (Cu-TpBpy-COF) in near-neutral condition. Cu-TpBpy-COF can effectively catalyze the oxidation of the colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) by oxygen to form a blue oxidized product (oxTMB) with an absorption peak at 652 nm. Cu is the active center of Cu-TpBpy-COF and pyrophosphate (PPi) can form a complex with Cu to weaken the catalytic activity of Cu-TpBpy-COF. In the presence of ALP, PPi is hydrolyzed into orthophosphates (Pi) with low affinity to Cu, thus resulting in absorbance restoration. The absorbance at 652 nm is related to ALP activity in the linear range 10-150 U·L with a detection limit of 7.17 U·L. The recoveries of ALP in serum samples are in the range 94.7~107.0% with relative standard deviations (RSD) lower than 5%. The decisive role of Cu on the enhancing catalytic activities of Cu-TpBpy-COF in neutral condition was verified by TpBpy-COF and TpBD-COF as controls, in which the main difference between them is that TpBpy-COF contains pyridine nitrogen. Upon Cu modification, Cu-TpBpy-COF has better catalytic activity than TpBpy-COF in a broader pH range because of the in situ generation of Cu under irradiation.
一种基于光响应氧化酶模拟物共价有机框架（Cu-TpBpy-COF）在近中性条件下催化活性的开-关效应的比色策略被开发用于检测碱性磷酸酶（ALP）活性。Cu-TpBpy-COF 可以有效地催化无色底物 3,3',5,5'-四甲基联苯胺（TMB）被氧气氧化生成蓝色氧化产物（oxTMB），其吸收峰在 652nm 处。Cu 是 Cu-TpBpy-COF 的活性中心，焦磷酸盐（PPi）可以与 Cu 形成复合物，从而削弱 Cu-TpBpy-COF 的催化活性。在存在 ALP 的情况下，PPi 被水解成与 Cu 亲和力低的正磷酸盐（Pi），从而导致吸光度恢复。在 652nm 处的吸光度与 ALP 活性在 10-150U·L 的线性范围内相关，检测限为 7.17U·L。在血清样品中，ALP 的回收率在 94.7%~107.0%之间，相对标准偏差（RSD）低于 5%。通过 TpBpy-COF 和 TpBD-COF 作为对照，验证了 Cu 在中性条件下对增强 Cu-TpBpy-COF 催化活性的决定性作用，它们之间的主要区别在于 TpBpy-COF 含有吡啶氮。Cu 修饰后，由于光照下原位生成 Cu，Cu-TpBpy-COF 在更宽的 pH 范围内具有比 TpBpy-COF 更好的催化活性。
