An aptamer electrochemical assay for sensitive detection of immunoglobulin E based on tungsten disulfide–graphene composites and gold nanoparticles

Abstract

Two-dimensional transition metal dichalcogenides are attracting increasing attention in electrochemical sensing due to their unique electronic properties. In this work, a label-free electrochemical assay for sensitive determination of IgE was developed by assembling aptamers on a glassy carbon electrode modified with WS₂–graphene nanosheets and gold nanoparticles. The WS₂–graphene nanosheet was prepared by a simple one-step hydrothermal process and its properties were characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The WS₂–graphene nanosheet acted as a relatively good electrical conductor for accelerating electron transfer, while the modification of gold nanoparticles provided signal amplification for electrochemical detection. The detection of IgE was performed by measuring the electrochemical signal response of [Fe(CN)₆]^3−/4− using differential pulse voltammetry. A good linear relationship between the peak current and the logarithm of IgE concentration from 1.0 × 10⁻¹² to 1.0 × 10⁻⁸ M was obtained with a detection limit of 1.2 × 10⁻¹³ M (3σ/S). The developed assay exhibited high sensitivity, selectivity and long-term stability, and it was successfully applied for the determination of IgE in serum samples. This work indicated that WS₂–graphene nanosheets were promising in electrochemical detection applications.