磷酸盐调控的Luminol-Tb荧光探针对炭疽杆菌生物标志物的比率检测

Phosphate-Modulated Luminol-Tb Fluorescent Probe for the Ratiometric Detection of Anthrax Biomarker

摘要: 实现对炭疽杆菌的灵敏选择性检测对预防炭疽病感染具有重要意义。本工作构建了基于磷酸根(Pi)调控的鲁米诺(Luminol)-Tb³⁺荧光配合物(Luminol-Tb-Pi)用于炭疽杆菌生物标志物(2,6-吡啶二羧酸，DPA)的快速、灵敏以及可视化检测。以Luminol为有机配体，Tb³⁺为中心离子，在Pi的调控下，DPA可使Tb³⁺特征荧光显著增强，同时引起Luminol荧光淬灭。DPA可作为Tb³⁺的天线配体敏化Tb³⁺发光，Pi通过缩小DPA与Tb³⁺之间的距离，增强了DPA的敏化作用；此外，Pi通过与Tb³⁺的配位可以减少水分子对Tb³⁺荧光的淬灭，进一步增强Tb³⁺荧光。由于DPA与Tb³⁺的竞争性结合，使Luminol与Tb³⁺的配位作用减弱，部分Luminol成游离态，导致其荧光淬灭。基于该双荧光信号变化，实现了对DPA的比率荧光检测，定量范围为0.2~45 μM。此外，基于该传感体系的荧光颜色变化可实现对DPA的可视化检测。本工作开发的荧光传感方法操作简单、成本低，具有良好的应用潜力。

Abstract: Achieving sensitive and selective detection of Bacillus anthracis is of great significance for preventing anthrax infection. This work constructs a Luminol-Tb fluorescent complex based on phosphate (Pi) regulation (Luminol-Tb-Pi) for the rapid, sensitive, and visual detection of anthrax biomarker (2,6-pyridyldicarboxylic acid, DPA). Under the regulation of Pi, with Luminol as the organic ligand and Tb³⁺ as the central ion, DPA can significantly enhance the characteristic fluorescence of Tb³⁺ and cause quenching of Luminol. DPA acts as the antenna ligand of Tb³⁺ to sensitize its luminescence, and Pi enhances the sensitization of DPA by reducing the distance between DPA and Tb³⁺. In addition, the coordination of Pi with Tb³⁺ can reduce the quenching effect by water molecules, further enhancing Tb³⁺ fluorescence. Due to the competitive binding between DPA and Tb³⁺, the coordination between Luminol and Tb³⁺ is weakened, and some Luminol become free, leading to their fluorescence quenching. Based on the dual fluorescence signal, the ratiometric detection of DPA is achieved with a quantitative range of 0.2~45 μM. In addition, the visual detection of DPA can be achieved based on the fluorescence color change of this sensing system. The sensing method developed is simple, low cost, and possesses potential in actual applications.