Design of a Zn-MOF biosensor via a ligand “lock” for the recognition and distinction of S-containing amino acids

Abstract

Two new 2D Zn(II) metal–organic frameworks (MOFs) {[Zn₂(L)₂(μ₂-O)(H₂O)₃]·3DMA}_n (Zn-1) and [Zn₂(L)₂(2,2′-bipy)(μ₂-O)(H₂O)₂]_n (Zn-2) (H₂L = 2,5-thiophene dicarboxylic acid, bipy = 2,2′-dipyridyl) were designed and synthesized. Through the strategy of introducing bipy as a “lock”, Zn-1 was transferred to Zn-2via a crystal-to-crystal process, which showed significantly enhanced solvent and air stability compared to that of Zn-1. Without post modification, Zn-2 was used as an electrode modified material to construct sensors for the electrochemical recognition and distinction of S-containing amino acids, including L-cysteine, L-methionine and L-cystine.