Zheng Fangyuan, Guo Sihua, Zeng Fang, Li Jun, Wu Shuizhu
State Key Laboratory of Luminescent Materials and Devices, College of Materials Science and Engineering, South China University of Technology , Guangzhou 510640, China.
Anal Chem. 2014 Oct 7;86(19):9873-9. doi: 10.1021/ac502500e. Epub 2014 Sep 23.
Alkaline phosphatase (ALP) is an important diagnostic indicator for a number of human diseases since abnormal level of ALP is closely related to a variety of pathological processes; hence, the development of convenient and reliable assay methods for monitoring ALP is of great significance for medical sciences as well as biological diagnostics. Herein, we report the first ratiometric fluorescent sensing system for ALP. This sensing system consists of two components: the betaine-modified and positively charged polyethylenimine (PEI) and the negatively charged pyrene derivative containing one ALP-responsive phosphate group (Py-P, an aliphatic phosphate ester). In the absence of ALP, the two-component sensing system shows the excimer's emission of Py-P, since Py-P molecules complex with the positively charged polyelectrolyte via electrostatic interactions, leading to the formation of pyrene excimers. While in the presence of ALP, the phosphate moieties are cleaved from Py-P molecules due to the enzymatic reaction, thereby destroying the electrostatic interactions; as a result, the system displays the monomer emission of Py-P. This assay system is operable in aqueous media with a very low detection limit of 0.1 U/mL. The system is capable of detecting ALP in such biological fluid as serum, and this strategy may provide a new and effective approach for designing ratiometric sensing systems for detecting other biomolecules.
碱性磷酸酶（ALP）是多种人类疾病的重要诊断指标，因为ALP水平异常与多种病理过程密切相关；因此，开发方便可靠的ALP监测检测方法对医学和生物诊断都具有重要意义。在此，我们报道了首个用于ALP的比率荧光传感系统。该传感系统由两个组件组成：甜菜碱修饰的带正电荷的聚乙烯亚胺（PEI）和含有一个ALP响应性磷酸基团的带负电荷的芘衍生物（Py-P，一种脂肪族磷酸酯）。在没有ALP的情况下，双组分传感系统显示出Py-P的激基缔合物发射，因为Py-P分子通过静电相互作用与带正电荷的聚电解质复合，导致芘激基缔合物的形成。而在有ALP的情况下，由于酶促反应，磷酸部分从Py-P分子上裂解下来，从而破坏了静电相互作用；结果，该系统显示出Py-P的单体发射。该检测系统可在水性介质中运行，检测限低至0.1 U/mL。该系统能够检测血清等生物流体中的ALP，并且这种策略可能为设计用于检测其他生物分子的比率传感系统提供一种新的有效方法。
