A novel three-fold interpenetration 3D Cd-based coordination polymer for the sensing of glutamate in aqueous medium and calf serum

Abstract

As a special biomarker for many nervous system diseases, Glutamate (Glu) plays an important role in clinical application. Therefore, it is of great significance to sense Glu sensitively in aqueous medium or serum. Here, a novel three-fold interpenetration 3D framework of {[Cd (HTCPB) (4,4′-bbib)]·2H2O}n (1) (H3TCPB ​= ​1,3,5-tris(4-carbonylphenyloxy)benzene, 4,4′-bbib ​= ​4,4′-bis(benzoimidazo-1-yl)biphenyl) (1) has been successfully synthesized and characterized by single-crystal X-Ray diffraction (SCXRD), X-ray powder diffraction analyses (PXRD), thermogravimetric (TG) and X-ray photoelectron spectroscopy (XPS). Stability experiments show that 1 has excellent water and thermal stability. And luminescence experiments demonstrated that 1 can selectively and sensitively sense Glu in aqueous solution with the limit of detection (LOD) being 1.15 ​× ​10-7 ​M. Meanwhile, the detection concentration of 1 towards Glu in serum is 4.31 ​× ​10-5 ​M, which is far lower than that of Glu (4 ​× ​10-4 ​M) in the blood of patients with glioma. In addition, the interaction between carboxylate groups (-COOH) of H3TCPB ligands in 1 and amino-groups (−NH2) of Glu is mainly responsible for the turn-on phenomenon of 1. These results provide a platform of 1 for sensing Glu in clinical application.