Stepwise control of reduction of graphene oxide and quantitative real-time evaluation of residual oxygen content using EC-SPR for a label-free electrochemical immunosensor

Nan Fu Chiu, Cheng Du Yang, Chi Chu Chen, Chia Tzu Kuo

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The aim of this study was to develop an electrochemical surface plasmon resonance (EC-SPR) method for the stepwise reduction of graphene oxide (GO) by monitoring the real-time refractive index in an effort to control the residual oxygen functionality and conductivity in GO sheets, and then to enhance sensitivity to detect immunoaffinity. The EC-SPR technique acts as a real-time operating system to be used for the observation of oxygen chemical element on the surface of GO. Experimental results demonstrated that EC-SPR signals could quantitatively detect real-time changes in the refractive index of GO films during the stepwise removal of oxygen functional groups. Cyclic voltammetry (CV) in the initial cycles of the electrochemical reduction of GO showed that the oxygen content of the GO film declined by approximately 60%. The SPR angle shifts during the electrochemical reduction for 10, 50 and 100 CV cycles were 164, 218 and 223 mdeg, and the corresponding X-ray photoelectron spectroscopy (XPS) spectra carbon-to-oxygen (C/O) ratios were 17.35, 21.07 and 30.95, respectively. The obtained electrochemically-reduced graphene oxide (ERGO) film chip had a very high sensitivity to detect anti-BSA, and this electrochemical immunosensor was more sensitive than an SPR immunosensor. Our results confirm that this EC-SPR technique could be used to develop electrochemical biosensors with immediate modification of GO film surfaces.

Original languageEnglish
Pages (from-to)981-990
Number of pages10
JournalSensors and Actuators, B: Chemical
Volume258
DOIs
Publication statusPublished - 2018 Apr 1

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Keywords

  • Cyclic voltammetry (CV)
  • Electrochemical surface plasmon resonance (EC-SPR)
  • Electrochemically reduced graphene oxide (ERGO)
  • Graphene oxide (GO)
  • Immune detection

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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