CuS nanoparticles as a mimic peroxidase for colorimetric estimation of human blood glucose level

CuS nanoparticles (NPs) was synthesized through a simple and green method using water soluble precursor complex [CuL2(H2O)2]Cl2 (L=pyridine 2-carboxamide) and was characterized by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and UV–Vis spectroscopic techniques. The as-prepared CuS NPs (covellite) was demonstrated to possess intrinsic peroxidase-like activity using 3,3′,5,5′-tetramethylbenzidine (TMB), as a peroxidase substrate, in presence of H2O2 which show good affinity towards both TMB and H2O2. Using this TMB–H2O2 catalyzed color reaction; the CuS NPs was exploited as a new type of biosensor for detection and estimation of glucose through a simple, cheap and selective colorimetric method in a linear range from 2 to 1800 μM with a detection limit of 0.12 μM. On the basis of the developed reaction process, we can easily monitor human blood glucose level.