Nonenzymatic Electrochemical Sensing Platform Based on 2D Isomorphic Co/Ni-Metal–Organic Frameworks for Glucose Detection

Abstract

Two-dimensional metal-organic framework (MOF) crystalline materials possess promising potential in the electrochemical sensing process owing to their tunable structures, high specific surface area, and abundant metal active sites; however, developing MOF-based nonenzymatic glucose (Glu) sensors which combine electrochemical activity and environmental stability remains a challenge. Herein, utilizing the tripodic nitrogen-bridged 1,3,5-tris(1-imidazolyl) benzene (TIB) linker, Co²⁺ and Ni²⁺, two 2D isomorphic crystalline materials, including Co/Ni-MOF {[Co (TIB)]·2BF₄} (CTGU-31) and {[Ni(TIB)]·2NO₃} (CTGU-32), with a binodal (3, 6)-connected kgd topological net were firstly synthesized and fabricated with conducting acetylene black (AB). When modified on a glassy carbon electrode, the optimized AB/CTGU-32 (1:1) electrocatalyst demonstrated a higher sensitivity of 2.198 μA μM^-1 cm^-2, a wider linear range from 10 to 4000 μM, and a lower detection limit (LOD) value (0.09 μM, S/N = 3) compared to previously MOF-based Glu sensors. Moreover, AB/CTGU-32 (1:1) exhibited desirable stability for at least 2000 s during the electrochemical process. The work indicates that MOF-based electrocatalysts are a promising candidate for monitoring Glu and demonstrate their potential for preliminary screening for diabetes.