A smartphone-integrated dual-mode nanosensor based on Fe3O4@Au for rapid and highly selective detection of glutathione

[Display omitted] •The mimics enzymes that has the high catalytic activity of natural enzymes.•Fe3O4@Au exhibits enhanced intrinsic peroxidase-like activity.•The color changing of solution can be simply visualized by the naked eye.•RGB intensities were measured to quantify GSH concentration.•The on-site device for GSH determining based on smartphone and Fe3O4@Au was developed. A simple, rapid and straightforward method for detecting reduced glutathione (GSH) was developed supported on smartphone analysis software package and a peroxide simulated catalyst nanoparticles (Fe3O4@Au) system. The nanocomposite was prepared by self-assembling technique, and the characterization was carried out using transmission electron microscopy, Fourier transforms infrared, and X-ray diffractometer. Fe3O4@Au materials have catalyzed the oxidation of a typical colorimetric substrate in the presence of H2O2, with the color changes from colorless to green oxidized. A smartphone with a free self-developed app referred to as “Color Capture” was accustomed live the RGB (red–greenblue) values of color intensity within the Fe3O4@Au system and computationally convert them GSH concentrations. The smartphone detection system showed high property and sensitivity of GSH detection. It gave a constant correlation (R2 = 0.9973) between the colour intensity of I and the GSH concentration, with a linear vary of 0–0.25 mmol/L, and a detection limit of 0.013 μmol/L. The results obtained were most consistent with the results obtained in ultraviolet spectrophotometry. The colorimetric system is based on smartphone analysis software developed to detect GSH in actual samples with potential application values.