Biocompatible bimetallic Au-Ni doped graphitic carbon nitride sheets: A novel peroxidase-mimicking artificial enzyme for rapid and highly sensitive colorimetric detection of glucose

Abstract

We report herein, a novel two dimensional (2D) nanocomposite sensor towards detection of glucose via a simple colorimetric detection technique. The graphitic carbon nitride (g-C3N4) sheets are decorated with Au-Ni bimetallic nanoparticles with size ˜11 nm by a simple chemical reduction technique. The Au-Ni/g-C3N4 nanocomposites is found to possess intrinsic peroxidase like activity capable of catalysing the oxidation of 3,3ʹ,5,5ʹ-tetramethylbenzidine (TMB) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) in presence of H2O2 and exhibits substrate affinity much higher than biological horseradish peroxidase as well as other reported nanozymes. Also, there is a scanty of literature reports on bimetallic g-C3N4 based nanozymes towards detection of any biomolecules related to human life. The peroxidase like activity combined with glucose oxidase (GOx) helped in developing a simple, sensitive and a specific colorimetric method for glucose detection with a detection limit of 1.7 μM and a linear detection range between 0.5‒30 μM. The colorimetric method for detection of glucose was further successfully extended towards detection of glucose in real serum samples with comparable results to standard hospital method. Additionally, the nanocomposites are non-cytotoxic towards human umbilical vein endothelial cell line (HUVEC) which demonstrates its high biocompatibility and suitability for biosensor applications. Our results thus demonstrate that our method based on Au-Ni/g-C3N4 is reliable, economical, feasible and highly efficient.