A single-functionalized ligand single-Ln³⁺ based dual-emission Ln-MOF fluorescent sensor was established for portable and visual dipicolinic acid (DPA, Bacillus anthracis biomarker) detection. First, a theory calculation-based prediction model was developed for designing single-functionalized ligand single-Ln³⁺ dual-emission Ln-MOFs. The model consisted of three calculation modules: intramolecular hydrogen bonds, excited state energy levels, and coordination stability with Ln³⁺ of ligands. Tb³⁺ and Eu³⁺ were selected as metal luminescence centers, PTA-X (PTA: p-phthalic acid, X = NH₂, CH₃, H, OH) with different functional groups as one-step functionalization ligands, and the luminescent feature of four Tb-MOFs and four Eu-MOFs was predicted with the model. Coupled with prediction results and experimental verification results, Tb-PTA-OH was rapidly determined to be the sole dual-emission Ln-MOF. Then, Tb-PTA-OH was applied to DPA detection by ratiometric fluorescence, and an ultra-low limit of detection (13.4 nM) was obtained, which is much lower than the lowest anthrax infectious dose (60 μM). A portable visual assay method based on paper-microchip and smartphone integrated mini-device was further established (limit of qualification 0.48 μM). A new sensing mechanism and a "triple gates" selectivity mechanism to DPA were proposed. This work reveals guidelines for material design and mini-device customization in detecting hazardous substances.

建立了一种基于单功能化配体单Ln ³⁺的双发射Ln-MOF 荧光传感器，用于便携式和可视化的吡啶二羧酸（DPA，炭疽杆菌生物标志物）检测。首先，开发了一种基于理论计算的预测模型，用于设计单功能化配体单 Ln ³⁺双发射 Ln-MOF。该模型由三个计算模块组成：分子内氢键、激发态能级和与Ln ³⁺配体的配位稳定性。选择Tb ³⁺和Eu ³⁺作为金属发光中心，PTA-X（PTA：对苯二甲酸，X=NH ₂，CH ₃, H, OH) 以不同的官能团作为一步功能化配体，利用该模型预测了四种 Tb-MOFs 和四种 Eu-MOFs 的发光特性。结合预测结果和实验验证结果，快速确定 Tb-PTA-OH 是唯一的双发射 Ln-MOF。然后，将Tb-PTA-OH应用于比率荧光法检测DPA，获得了超低检测限（13.4 nM），远低于最低炭疽感染剂量（60 μM）。进一步建立了一种基于纸-微芯片和智能手机集成微型设备的便携式视觉检测方法（限定0.48 μM）。提出了一种新的传感机制和对DPA的“三重门”选择性机制。