Label-free aptamer sensor for 17β-estradiol based on vanadium disulfide nanoflowers and Au nanoparticles

Two-dimensional transition metal dichalcogenide are attracting increasing attention in electrochemical sensing due to unique nanoconstruction and electronic properties. The present work reports the preparation of flower-like vanadium disulfide (VS2) by a simple one-step hydrothermal process and its properties are characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Data from XRD, SEM and TEM demonstrate that the as-prepared VS2 product has ordered nanosheets stacking flower-structure which is constructed with many irregular nanosheets as a petal-like structure with thickness of several nanometers. A novel electrochemical biosensor was constructed for the determination of 17β-estradiol by immobilizing aptamer on the surface of VS2 nanoflowers and gold nanoparticles modified glassy carbon electrode. Differential pulse voltammetry is applied for the determination of 17β-estradiol and a good linear relationship between the peak current and the logarithm of 17β-estradiol concentration from 1.0 × 10−11 to 1.0 × 10−8 M with a detection limit of 1.0 × 10−12 M (3σ/S). The aptamer sensor exhibits a high sensitivity and remarkable reproducible analytical performance, and was successfully applied for the determination of 17β-estradiol in urine samples with recoveries of 92.0-105.2%. Our attempt will extend the application of VS2 nanoflowers to electrochemical biosensing and catalytic areas.