Luminescent Metal-Organic Framework Sensor for Detection of Biomarker 2-Thiothiazolidine-4-Carboxylic acid

Abstract

Using terephthalic acid (BDC) as the organic ligand and zirconium chloride (ZrCl4) as the metal source, a lanthanide metal-organic framework (Tb/Zr-UiO-66) with excellent luminescence properties was successfully prepared by introducing the lanthanide ion Tb3+ in situ through a simple one-pot hydrothermal reaction, which was designed as an optical biosensor for 2-thiothiazolidine-4-carboxylic acid (TTCA), the urinary biomarker of human exposure to carbon disulfide (CS2). The fabricated Tb/Zr-UiO-66 exhibits high chemical and luminescent stability, making it competent for recognizing TTCA in aqueous environments. Significantly, its luminescence intensity change shows a good linearity relationship with the concentration of TTCA in the range of 0-110 μM, with a limit of detection (LOD) as low as 0.14 μM. Meanwhile, this sensor exhibits good selectivity and anti-interference ability towards TTCA among the various coexisting components in urine (Na+, K+, NH4+, SO42−, Cl −, creatine, creatinine, glucose, urea, etc.), and can quickly respond to TTCA within 2 minutes. The analysis results of PXRD, fluorescence lifetime and UV-vis spectrum demonstrate that the sensing mechanism can be ascribed to the competition absorption effect between TCAA and Tb/Zr-UiO-66. This biosensor with simple synthesis, stable framework, high sensitivity and selectivity, and rapid response has potential to become a powerful tool for diagnosing diseases associated with CS2 exposure.