Nanostruetured FeS as a mimic peroxidase for biocatalysis and biosensing

Artificial enzyme mimics have attracted considerable interest due to easy denaturation and leakage of enzymes during their storage and immobilization procedure. Herein we describe the design of a novel mimic peroxidase, a nanostructure of sheet-like FeS prepared by a simple micelle-assisted synthetic method. Such a nanostructure has a large specific surface area and high peroxidase-like activity, and was thus further used as a mimic enzyme for the development of biocat-alysts and amperometric biosensors. The sheet-like FeS nanostructure showed typical Michaelis-Menten kinetics and good affinity to both H₂O₂ and 3,3',5,5'-tetramethyl benzidine. At pH 7.0 the constructed amperometric sensor showed a linear range for the detection of H₂O₂ from 0.5 to 150 μM with a correlation coefficient of 0.9998 without any electron transfer mediator. The H₂O₂ sensor based on the sheet-like FeS showed more sensitive response than those based on spherical FeS nanostructure, and resulted in a better stability than horseradish peroxidase when they were exposed to solutions with different pH values and temperatures. These excellent properties made the sheet-like nanostruetured FeS powerful tools for a wide range of potential applications as an "artificial peroxidase" as biosensors and biotechnology.