Zeolitic Imidazolate Framework-Based Electrochemical Biosensor for in Vivo Electrochemical Measurements

Abstract

This study demonstrates the first exploitation of zeolitic imidazolate frameworks (ZIFs) as the matrix for constructing integrated dehydrogenase-based electrochemical biosensors for in vivo measurement of neurochemicals, such as glucose. In this study, we find that ZIFs are able to serve as a matrix for coimmobilizing electrocatalysts (i.e., methylene green, MG) and dehydrogenases (i.e., glucose dehydrogenase, GDH) onto the electrode surface and an integrated electrochemical biosensor is readily formed. We synthesize a series of ZIFs, including ZIF-7, ZIF-8, ZIF-67, ZIF-68, and ZIF-70 with different pore sizes, surface areas, and functional groups. The adsorption capabilities toward MG and GDH of these ZIFs are systematically studied with UV-vis spectroscopy, confocal laser scanning microscopy, and Fourier transfer-infrared spectroscopy. Among all the ZIFs demonstrated here, ZIF-70 shows excellent adsorption capacities toward both MG and GDH and is thus employed as the matrix for our glucose biosensor. To construct the biosensor, we first drop-coat a MG/ZIF-70 composite onto a glassy carbon electrode and then coat GDH onto the MG/ZIF-70 composite. In a continuous-flow system, the as-prepared ZIF-based biosensor is very sensitive to glucose with a linear range of 0.1-2 mM. Moreover, the ZIF-based biosensor is more highly selective on glucose than on other endogenous electroactive species in the cerebral system. In the end, we demonstrate that our biosensor is capable of monitoring dialysate glucose collected from the brain of guinea pigs selectively and in a near real-time pattern.

Exceptionally Long-Lived Charge Separated State in Zeolitic Imidazolate Framework: Implication for Photocatalytic Applications

“…[3][4][5][6] Thus, ZIFs demonstrate great promise in various applications such as gas separation and storage, [6][7][8][9][10][11] chemical sensing, 12 and heterogeneous catalysis. [13][14][15][16][17] Driven by the increasing global energy demand, recent development in the field has extended the application of ZIF materials toward photocatalysis using visible light.…”

Highly efficient electrochemical recognition and quantification of amine enantiomers based on a guest-free homochiral MOF

“…20 In addition, there are few studies to incorporate the functionality of achiral MOFs and its derivatives into enzyme biosensor applications. [24][25][26] To the best of our knowledge, until now no reports have been found regarding CMOFs for selective chiral detection. On the other hand, aiming at practical applications, the CMOFs must retain their structural integrity in both cases, the aqueous environment and the removal of the guest molecules trapped in the channels for creating empty pores and accessible metal sites.…”

Zeolitic Imidazolate Framework-67 Rhombic Dodecahedral Microcrystals with Porous {110} Facets As a New Electrocatalyst for Sensing Glutathione

“…[ 34 ] Chen et al showed that ZIF-67 was used as a promising formaldehyde gas sensor. [ 35 ] Wang et al reported the water oxidation electrocatalysis by a zeolitic imidazolate framework.…”

“…All diffraction peaks correspond well to a pure cubic ZIF-67 and match well with the simulated as well as the published results. [ 34 ] ZIF-67 has three-dimensional zeolite-like structure with SOD topology as shown in the inset of Figure 1 a. In addition, gas sorption properties of the as-prepared ZIF-67 samples are also studied.…”