Electrochemical aptasensor for detecting Der p2 allergen using polycarbonate-based double-generation gold nanoparticle chip

Abstract

In this study, a novel aptamer-based impedimetric biosensor for detecting the group 2 allergen of Dermatophagoides pteronyssinus (Der p2) was developed. First, an anodic aluminum oxide (AAO) membrane was prepared. A modified AAO barrier-layer surface with an array of nanohemispheres of 400nm in diameter was used as a template for the nanoelectroforming of a nickel mold. After electroforming, the AAO template was etched and a nickel nanomold with a concave nanostructure array was produced. The formed nanostructured nickel nanomold was then used in the replica molding of a nanostructured polycarbonate (PC) substrate via hot embossing. Finally, a gold thin film was sputtered onto the PC substrate to form a double-generation gold nanoparticle electrode (array of nanohemispheres with smaller nanoparticles orderly distributed on each nanohemisphere). After immobilizing specifically designed aptamers on the fabricated electrode, electrochemical impedance spectroscopy was used to determine the concentration of Der p2. The sensitivity of the proposed scheme for the detection of the dust mite antigen Der p2 was 2.088Ω/(ng/mL×cm2) with a dynamic detection range of 27.5–400ng/mL and detection limit of 16.47ng/mL.The aptamer-based impedimetric biosensor proposed in this study possesses many advantages such as high sensitivity, low cost, and high consistency over currently used sensors. The proposed sensor was found to be useful for the rapid detection of rare molecules present in an analyte.