基于半导体聚合物量子点的羧酸酯酶比率荧光传感

建立了以半导体聚合物聚[(9,9-二辛基芴)]量子点(PFO Pdots)为荧光探针的羧酸酯酶(CaE)比率型荧光传感方法.带负电荷的PFO Pdots与带正电荷的聚乙烯亚胺(PEI)通过静电作用形成纳米复合物Pdots@PEI,在440和467 nm处有两个荧光发射峰.在CaE作用下,CaE的底物荧光素二乙酸酯(FDA)水解生成带负电的产物荧光素,此物质与带正电荷的Pdots@PEI之间由于静电作用距离拉近,两者可以发生共振能量转移,导致能量供体Pdots@PEI的荧光强度逐渐减弱,而荧光素的荧光强度逐渐增强.基于Pdots@PEI的荧光减弱和荧光素的荧光增强所构成的荧光强度比率关系,建立了选择性检测CaE的新方法.在最优实验条件下,本方法对CaE检测的线性范围为0.75~50.00 U/L,检出限为0.75 U/L(S/N=3).将本方法用于兔血液中CaE含量的检测,结果令人满意.

A Ratiometric Fluorescence Sensing for Carboxylesterase Based on Semiconducting Polymer Quantum Dots

A carboxylesterase ( CaE ) ratiometric fluorescent probe based on semiconducting Poly ( 9 , 9-dioctylfluorenyl-2,7-diyl) (PFO) polymer quantum dots (Pdots) was prepared. The negatively charged PFO Pdots and the positively charged polyethyleneimine ( PEI) formed a nanocomposite Pdots@PEI by electrostatic interaction, and emitted fluorescence at 440 nm and 467 nm. In the presence of CaE, the substrate fluorescein diacetate ( FDA ) was hydrolyed into negatively charged fluorescein molecule, and could get closer to the positively charged Pdots@PEI due to electrostatic interactions, which could induce resonance energy transfer, resulting in the energy donor Pdots@ PEI fluorescence intensity gradually weakened and the fluorescence intensity of the FDA hydrolysis product increased. Based on the fluorescence intensity ratio of Pdots@PEI and the fluorescence enhancement of FDA hydrolysis products, a new method for selective detection of CaE was established. Under the optimal conditions, the linear range of the method on CaE testing was 0. 75-50 U/L with detection limits of 0 . 75 U/L ( S/N=3 ) . This method was used for the detection of the content of CaE in rabbit blood with satisfactory results.