摘要/Abstract
重要生物标志物例如碱性磷酸酶（ALP）的高灵敏度检测和准确分析对于疾病的早期检测和治疗至关重要.本工作合成了Cu基金属有机框架材料HKUST-1，探索了其类氧化酶性质.通过设计HKUST-1模拟酶与ALP天然酶的级联催化体系，构建了高灵敏度及高选择性的荧光/紫外双模式检测平台，用于生物标志物ALP及焦磷酸根离子（PPi）的检测.利用所设计的级联催化反应对信号的有效放大以及荧光和紫外双信号输出，对ALP的检测限分别低至0.0078和0.039 nmol·L-1.本工作首次开发了基于模拟酶-天然酶级联催化放大的双模式生物分析方法，实现了两种生物标志物的灵敏检测以及酶抑制剂的抑制效率评估，并将其应用到人血清样品中ALP的超灵敏分析，在临床诊断中具有巨大应用潜力.
关键词: 生物标志物检测, 碱性磷酸酶, 双模式检测, 模拟酶, 生物传感
Highly sensitive and accurate analysis of significant biomarkers such as alkaline phosphatase (ALP) is essential for early detection and treatment of diseases. In this work, a fluorescence/UV-vis dual-mode sensing platform was constructed for amplified detection of ALP and pyrophosphate ion (PPi) based on mimic enzyme-natural enzyme cascade reactions. Cu-Based metal-organic frameworks HKUST-1 which possesses of oxidase-like activity and can effectively catalyze the oxidation of indicator o-phenylenediamine (OPD) by the surface-active sites were prepared. The oxidation products of OPD exhibit strong UV-vis absorption and fluorescent signals at 416 and 568 nm, respectively. After adding PPi, the catalytic activity of HKUST-1 was selectively inhibited due to the combination of PPi with Cu2+ on the surface of HKUST-1, that resulted in fluorescence and UV-vis signal reducing. Once ALP was introduced into the system, PPi can be specifically hydrolyzed into phosphate ions (Pi), and the oxidase-like activity of HKUST-1 recovered. Thus, the fluorescent and UV-vis signals were regenerated by an ALP-triggered mimic enzyme-natural enzyme cascade reaction. On account of the inhibition of oxidase-like activity of HKUST-1 by PPi and the recovery by ALP, an ultrasensitive dual-mode sensing platform of biomarkers based on mimic enzyme-natural enzyme cascade reactions has been developed. Under optimal conditions, the linear range of ALP by fluorescence/UV-vis detection is 0.02~3.5 and 0.04~3.5 nmol·L-1, and the detection limit of fluorescence and UV-vis assay is as low as 0.0078 and 0.039 nmol·L-1, respectively. As far as we know, it is the first time that the mimic enzyme-natural enzyme cascade reaction is applied to dual-mode bioanalysis. Due to the enzyme cascade amplification and dual-mode signal output, this developed strategy has the advantages of high sensitivity, low detection limit, high accuracy and reliability, and can realize ultrasensitive analysis of ALP in human serum samples, which shows great potential for clinical diagnosis.
Key words: biomarker detection, alkaline phosphatase, dual-mode detection, mimic enzyme, biosensing
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