Synthesis of the multi-walled carbon nanotubes-COOH/graphene/gold nanoparticles nanocomposite for simple determination of Bilirubin in human blood serum

Abstract

In this work, the multi-walled carbon nanotubes-COOH (MWCNTs-COOH)/graphene (GNs)/gold nanoparticles (AuNPs) composite materials were synthesized by in situ growth of AuNPs on the surface of the MWCNTs-COOH/GNs. And then, the Bilirubin oxidase (BUD) was immobilized on the surface of the film to construct a biosensor for determination of Bilirubin. Morphology of the nanomaterials was analyzed by field-emission scanning electron microscopy, high resolution transmission electron microscopy, Brunauer–Emmett–Teller, and X-ray photoelectron spectroscopy. The performance of the biosensor was studied by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and amperometric response (i–t). It was demonstrated that the nanocomposite materials exhibited enhanced fast electron transfer and excellent biocompatibility. In this assay, the MWCNTs-COOH/GNs/AuNPs composite film based biosensor showed prominently electrocatalytic activity for the detection of Bilirubin with a linear range from 1.33μM to 71.56μM and the low limit of detection (LOD) is 0.34μM based on a signal to noise ratio (S/N=3). Meanwhile, the apparent Michaelis–Menten constant (Km) was 64.86μM. In addition, this biosensor exhibited satisfying reproducibility, stability, feasibility and fast responses. These results provide a novel way for exact detection of Bilirubin in biotechnology and clinical diagnosis, and broaden the application of graphene and carbon nanotubes in biomaterials.