Elsevier

Biosensors and Bioelectronics

Volume 25, Issue 5, 15 January 2010, Pages 1070-1074
Biosensors and Bioelectronics

Graphene/AuNPs/chitosan nanocomposites film for glucose biosensing

https://doi.org/10.1016/j.bios.2009.09.024Get rights and content

Abstract

A novel glucose biosensor based on immobilization of glucose oxidase in thin films of chitosan containing nanocomposites of graphene and gold nanoparticles (AuNPs) at a gold electrode was developed. The resulting graphene/AuNPs/chitosan composites film exhibited good electrocatalytical activity toward H2O2 and O2. The wide linear response to H2O2 ranging from 0.2 to 4.2 mM (R = 0.998) at −0.2 V, high sensitivity of 99.5 μA mM−1 cm−2 and good reproducibility were obtained. The good electrocatalytical activity might be attributed to the synergistic effect of graphene and AuNPs. With glucose oxidase (GOD) as a model, the graphene/AuNPs/GOD/chitosan composite-modified electrode was constructed through a simple casting method. The resulting biosensor exhibited good amperometric response to glucose with linear range from 2 to 10 mM (R = 0.999) at −0.2 V and from 2 to 14 mM (R = 0.999) at 0.5 V, good reproducibility and detection limit of 180 μM. Glucose concentration in human blood was studied preliminarily. From 2.5 to 7.5 mM, the cathodic peak currents of the biosensor decrease linearly with increasing the glucose concentrations. The graphene/AuNPs/GOD/chitosan composites film shows prominent electrochemical response to glucose, which makes a promising application for electrochemical detection of glucose.

Introduction

Electrochemical biosensors based upon nanomaterials have recently attracted considerable attention (Pandey et al., 2008, Valentini and Palleschi, 2008, Willner et al., 2007). The electrochemical method has many advantages, such as high sensitivity, good selectivity, fast detection and low cost, so a lot of electrochemical sensors with high sensitivity and selectivity toward many analytes have been prepared (Ahmed et al., 2008, Drummond et al., 2003). Due to their unique chemical and physical properties, many kinds of nanomaterials, such as gold nanoparticles (AuNPs) (Pingarron et al., 2008, Yanez-Sedeno and Pingarron, 2005), carbon nanotubes (Azamian et al., 2002, Lin et al., 2005, Rivas et al., 2007), metallic oxides (Hsing et al., 2007, Yang et al., 2004) and semiconductors (Vastarella and Nicastri, 2005) have been used widely in fabrication of biosensors for medical analysis, environmental monitoring, food quality control, etc. Especially, the unique properties of gold nanoparticles to provide a suitable microenvironment for biomolecules immobilization retaining their biological activity, and to facilitate electron transfer between the immobilized proteins and electrode substrates, have led to an intensive use of those nanomaterials for the construction of electrochemical biosensors with enhanced analytical performance with respect to other biosensor designs (Jia et al., 2008, Li et al., 2007b, Pingarron et al., 2008, Raj et al., 2005, Shen et al., 2005, Yang et al., 2007, Zhang et al., 2004b).

Graphene, a single layer of carbon atoms in a closely packed honeycomb two-dimensional lattice, has attracted considerable attention from both experimental and theoretical scientific communities in recent years (Geim and Novoselov, 2007, Li et al., 2008a). Due to their novel properties (Li et al., 2008b, Zhang et al., 2005) such as exceptional thermal and mechanical properties, high electrical conductivity, the graphene sheets have exhibited potential applications in synthesizing nanocomposites (Muszynski et al., 2008, Stankovich et al., 2006, Williarris et al., 2008, Xu et al., 2008) and fabricating various electrical devices, such as battery (Cassagneau and Fendler, 1998), field-effect transistors (Gilje et al., 2007), ultrasensitive sensors (Schedin et al., 2007) and electromechanical resonators (Bunch et al., 2007). Recently, biological and electrocatalytic applications of graphene have also started to be concerned. Dai et al. synthesized nanoscale graphene oxide sheets by branched polyethylene glycol (PEG) and they exhibited unique ability of graphene in the attachment and delivery of aromatic, water insoluble drugs (Liu et al., 2008). Berry et al. fabricated a novel graphene-based live-bacterial-hybrid device and a DNA-hybridization device with excellent sensitivity (Mohanty and Berry, 2008). Li and Wallace et al. have presented the growth of mouse fibroblast cell (L-929) on graphene paper, which indicated that the graphene paper was biocompatible and suitable for biomedical applications (Chen et al., 2008). Our group also constructed a graphene-based electrochemical glucose biosensor, which exhibited potential application of graphene in biosensors (Shan et al., 2009). However, studies to use the nanocomposites of graphene and AuNPs for electrochemical biosensor have not been reported as far as we know.

Chitosan with abundant amino groups exhibits good biocompatibility (Liu et al., 2005) and excellent film-forming ability originating from its protonation and solubility in slightly acidic solution and stability from insolubility in solution with pH over pKa (6.3) (Sorlier et al., 2001). So it is a very suitable matrix for immobilizing bioactive molecules and constructing biosensors. Here, we constructed a novel enzyme immobilization matrix intended to combine the above-mentioned benefits of AuNPs, graphene and chitosan for biosensing applications. The resulting graphene–AuNPs–chitosan composites showed obvious electrocatalysis toward H2O2 and O2. Further, when glucose oxidase (GOD) was immobilized into graphene–AuNPs–chitosan composites film, the resulting electrodes demonstrated favorable linear response to glucose.

Section snippets

Materials

Graphite, hydrazine solution (50 wt%), ammonia solution (28 wt%) and chitosan were purchased from Sinopharm Chemical Reagent Co., Ltd. Polyvinylpyrrolidone (Mw = 360,000; PVP), HAuCl4·3H2O and NaBH4 were obtained from Aldrich. Glucose oxidase (GOD, EC 1.1.3.4, Type X-S, lyophilized powder, 100–250 units/mg, from Aspergillus niger) and d-(+)-glucose (≥99.5%) were obtained from Sigma. Glucose stock solutions were stored overnight at room temperature before use. Hydrogen peroxide solution (30 wt%

Characterizations of AuNPs-decorated graphene

The PVP-protected graphene was synthesized as our previous report (Shan et al., 2009). The successful synthesis of AuNPs-decorated graphene was confirmed by UV–vis spectroscopy (Fig. 1). The UV–vis spectrum of graphene oxides (curve a in Fig. 1) in water shows an absorption peak at 230 nm. After formation of PVP-graphene through the hydrazine reduction, the peak of PVP-protected graphene (curve b) is observed at 270 nm. The absorption of PVP-protected graphene redshifts from 230 to 270 nm,

Conclusion

In sum, we have successfully constructed a novel and biocompatible graphene/AuNPs/chitosan nanocomposites at the electrode. The resulting graphene/AuNPs/chitosan electrode showed high electrocatalytic activity toward H2O2 and O2. The synergistic effect of graphene and AuNPs may promote the electrocalalysis toward H2O2. The high sensitivity and good stability at such a modified electrode led us to construct a practical glucose biosensor successfully, which could also be extended to the

Acknowledgement

The authors are most grateful to the NSFC, China (Nos. 20673109 and 20827004) and Ministry of Science and Technology (Nos. 2007AA03Z354 and 2007BAK26B06) for their financial support. This work is also part of the activities of the Åbo Akademi Process Chemistry Centre, Centre of Excellence in research nominated by the Academy of Finland for 2001–2011.

References (50)

  • H.S. Chen et al.

    Diabetes Res. Clin. Pract.

    (1998)
  • K.S. Dai et al.

    Clin. Chim. Acta

    (2004)
  • F. Jia et al.

    Biosens. Bioelectron.

    (2008)
  • X.H. Kang et al.

    Talanta

    (2008)
  • J.W. Li et al.

    Anal. Chim. Acta

    (2007)
  • Y. Liu et al.

    Biosens. Bioelectron.

    (2005)
  • J.M. Pingarron et al.

    Electrochim. Acta

    (2008)
  • C.R. Raj et al.

    Electrochem. Commun.

    (2005)
  • G.A. Rivas et al.

    Talanta

    (2007)
  • W. Vastarella et al.

    Talanta

    (2005)
  • I. Willner et al.

    Bioelectrochemistry

    (2007)
  • M. Yang et al.

    Biosens. Bioelectron.

    (2007)
  • M.H. Yang et al.

    Biosens. Bioelectron.

    (2006)
  • Y.H. Yang et al.

    Anal. Chim. Acta

    (2004)
  • J.J. Yu et al.

    Talanta

    (2008)
  • M.U. Ahmed et al.

    Electroanalysis

    (2008)
  • B.R. Azamian et al.

    J. Am. Chem. Soc.

    (2002)
  • J.S. Bunch et al.

    Science

    (2007)
  • T. Cassagneau et al.

    Adv. Mater.

    (1998)
  • H. Chen et al.

    Adv. Mater.

    (2008)
  • H.N. Choi et al.

    Electroanalysis

    (2007)
  • T.G. Drummond et al.

    Nat. Biotechnol.

    (2003)
  • A.K. Geim et al.

    Nat. Mater.

    (2007)
  • S. Gilje et al.

    Nano Lett.

    (2007)
  • I.M. Hsing et al.

    Electroanalysis

    (2007)
  • Cited by (0)

    View full text