Highly Porous 3D\nNi-MOFs as an Efficient and Enzyme-Mimic\nElectrochemical Sensing Platform for Glucose in Real Samples of Sweat\nand Saliva in Biomedical Applications

Nickel-based metal–organic frameworks, denoted\nas three-dimensional\nnickel trimesic acid frameworks (3D Ni-TMAF), are gaining significant\nattention for their application in nonenzymatic glucose sensing due\nto their unique properties. Ni-MOFs possess a high surface area, tunable\npore structures, and excellent electrochemical activity, which makes\nthem ideal for facilitating electron transfer and enhancing the catalytic\noxidation of glucose. This research describes a new electrochemical\nenzyme-mimic glucose biosensor in biological solutions that utilizes\n3D nanospheres Ni-TMAF created layer-by-layer on a highly porous nickel\nsubstrate. The Ni-TMAF based on the nonenzymatic electrochemical glucose\noxidation represent the promising approach, leveraging the unique\nproperties of Ni-TMAF to provide efficient, stable, and potentially\nmore cost-effective alternatives to traditional enzyme-mimic sensors.\nThe MOF is synthesized from trimesic acid (TMA) and nickel nitrate\nhexahydrate through a solvothermal reaction process. The resulting\nNi-TMAF utilizes the three-dimensional nanospheres of crystalline\nporous structure with a large surface area and numerous active sites\nfor catalytic reaction toward glucose. Ni-TMAF are indeed known for\ntheir excellent electrocatalytic activity, particularly in the context\nof glucose oxidation under alkaline conditions. The nickel centers\nin the Ni-TMAF facilitate efficient electron transfer and redox reactions,\nleading to the high sensitivity of 203.89 μA μM<sup>–1</sup> cm<sup>–2</sup> and lower LOD of 0.33 μM and fast response\ntime of <3 s in glucose sensors. Their stability, cost-effectiveness,\nand high performance make 3D Ni-TMAF a promising material for nonenzymatic\nelectrochemical glucose sensors.