Selective and sensitive detection of cholesterol using intrinsic peroxidase-like activity of biogenic palladium nanoparticles

Biogenic palladium nanoparticles (Pd NPs) based colorimetric sensing and detection of cholesterol is being reported. Pd NPs used in this method were synthesized using gum kondagogu (GK), a biopolymer, which acted as both reducing and stabilizing agent. The GK reduced / stabilized Pd NPs (GK-Pd NPs) were directly used for the selective and colorimetric detection of cholesterol without any further modification. Cholesterol is known to be catalyzed by cholesterol oxidase (ChOx) and H2O2 produced in the reaction. The intrinsic peroxidase activity of GK-Pd NPs was coupled with catalytic oxidation of cholesterol by ChOx to colorimetric oxidation of 3, 3, 5, 5-tetramethylbenzidine (TMB) for the detection of cholesterol. Under the optimal conditions, the absorbance was proportional to the concentration of cholesterol over the range of 5-100 mu M and the limit of quantification (LOQ) was recorded to be 3.7 mu M. Moreover, the practicability of the assay in the detection of cholesterol in human serum was validated with promising results and has potential application in clinical diagnosis due to its selectivity and sensitivity.