▎ 摘　　要

In this paper, a simple, ultrasensitive and label-free electrochemical alpha 2,6-sialylated glycans biosensor based on reduced graphene oxide-tetraethylene pentamine-1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) hybrids was developed. Due to the abundance of amino groups from reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) and the electrostatic interaction of BMIMPF6, bimetallic gold platinum alloy nanoparticles (AuPtNPs) were densely adsorbed onto the surface of the nanocomposite, providing a large surface area available for the immobilization of Sambucus nigra agglutinin (SNA). AuPtNPs have excellent conductivity and catalytic activity, which can promote electron transfer between the electrolyte solution and the surface of electrode and can enhance the sensitivity of biosensor. SNA, which specifically binds alpha 2,6-sialylated glycans, was covalently immobilized on AuPtNPs for specific detection of alpha 2,6-sialylated glycans in human serum. Under optimal experimental conditions, amperometric response changes were used to detect alpha 2,6-sialylated glycans with a broad linear range of 10 fg mL(-1)-1 mu g mL(-1) and a low detection limit of 3 fg mL(-1) (S/N=3). When applied to spiked serum samples, the recovery of the developed biosensor ranged from 100.8% to 101.4%, suggesting that the electrochemical biosensor would be suitable for the practical detection of alpha 2,6-sialylated glycans. (C) 2015 Elsevier B.V. All rights reserved.