NiFe layered double hydroxide nanosheets as an efficiently mimic enzyme for colorimetric determination of glucose and H2O2

The ultrathin NiFe-layered double hydroxide nanosheets (NiFe-LDHNS) were prepared by exfoliating bulk LDH in l-asparagine aqueous medium. The transmission electron microscopy and atomic force microscopy results reveal that NiFe-LDHNS have about 200-300 nm lateral size and less than 2 nm thickness with the broken edges rather than the original hexagon of hydrotalcite. The peroxidase-like activity of the 2D NiFe-LDHNS was investigated by using oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine in presence of H2O2. The 2D NiFe-LDHNS exhibited the superior enzyme mimic activity to the bulk NiFe-LDH, which was attributed to the more exposed active sites and more accessible inner surface of single or several layers. Thus, a simple and sensitive non-enzyme biosensor was developed for colorimetric detection of H2O2 and glucose. The proposed method was successfully applied to glucose detection in real samples with satisfactory results.