Colorimetric detection of cholesterol based on peroxidase mimetic activity of GoldMag nanocomposites

Abstract Herein, Gold and magnetic particles (GoldMag), an enzyme mimetic of horseradish peroxidase (HRP), have been designed to construct a colorimetric sensor for cholesterol (Cho). The well-dispersed GoldMag was successfully prepared by green reduction using a self-assembly method based on the surface amino groups, and characterized by Fourier transform infrared (FTIR), X-Ray Photoelectron Spectroscopic (XPS) techniques. In the presence of H2O2, the resulting nanocomposites possessed enhanced intrinsic peroxidase-like activity and could catalytically oxidize 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) to produce a green colored product, which could be observed apparently by the naked eye. Based on the outstanding catalytic activity, the designed colorimetric sensor displayed a linear response for cholesterol in the range from 0.1 mg/mL to 7.5 mg/mL with a detection limit as low as 0.003 mg/mL. The proposed method was validated to determine cholesterol in real samples with satisfactory results.