Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Xi'an 710062, PR China; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China.
Lab Center, the Third Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710049, PR China.
Biosens Bioelectron. 2015 Jun 15;68:648-653. doi: 10.1016/j.bios.2015.01.061. Epub 2015 Jan 29.
Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities (i.e., total AChE) in human blood are biomarkers for theranostic monitoring of organophosphate neurotoxin-poisoned patients. We developed an ultra-sensitive method to detect the total AChE activity in sub-microliter human whole blood based on in situ induced metal-enhanced fluorescence (MEF). Both AChE and BChE can catalyze the hydrolysis of the acetylthiocholine (ATCh) substrate and produce positively-charged thiocholine (TCh). TCh can reverse the negatively-charged surface of core-shell Ag@SiO2 nanoparticles (NPs). The negatively-charged fluorescent dye (8-hydroxypyrene-1,3,6-trisulfonic acid, HPTS) is then confined to the surface of Ag@SiO2 NPs and generates an enhanced fluorescence signal in situ. Changes in the surface charge of Ag@SiO2 NPs are monitored by Zeta potential, and the MEF effect is confirmed by the measurements of fluorescence time decay. AChE activity has a dynamic range of 0 U/mL to 0.005 U/mL and a detection limit of 0.05 mU/mL. The total AChE activity in the sub-microliter human whole blood could be determined; the results were further validated. Therefore, combining the AChE catalytic reaction with MEF provides a simple, ultra-sensitive, and cost-effective "in situ MEF" approach to determine the total AChE activity in human whole blood sample down to sub-microliters without matrix interferences. The strategy also allows potential usage in other tissues and other fields.
乙酰胆碱酯酶（AChE）和丁酰胆碱酯酶（BChE）在人血液中的活性（即总 AChE）是有机磷神经毒素中毒患者治疗监测的生物标志物。我们开发了一种超灵敏的方法，基于原位诱导的金属增强荧光（MEF）来检测亚微升人全血中的总 AChE 活性。AChE 和 BChE 都可以催化乙酰硫代胆碱（ATCh）底物的水解，并产生带正电荷的硫代胆碱（TCh）。TCh 可以逆转核壳 Ag@SiO2 纳米粒子（NPs）的带负电荷表面。然后，带负电荷的荧光染料（8-羟基芘-1,3,6-三磺酸，HPTS）被限制在 Ag@SiO2 NPs 的表面，并在原位产生增强的荧光信号。通过 Zeta 电位监测 Ag@SiO2 NPs 表面电荷的变化，并通过荧光时间衰减测量来证实 MEF 效应。AChE 活性的动态范围为 0 U/mL 至 0.005 U/mL，检测限为 0.05 mU/mL。可以测定亚微升人全血中的总 AChE 活性，并进一步验证了结果。因此，将 AChE 催化反应与 MEF 相结合，提供了一种简单、超灵敏、经济高效的“原位 MEF”方法，可在无基质干扰的情况下，测定亚微升人全血样本中的总 AChE 活性。该策略还允许在其他组织和其他领域中具有潜在的应用。
