Reduced Graphene-Oxide Transducers for Biosensing Applications Beyond the Debye-Screening Limit

Xiaoling Lu, Anna Miodek, Walid Munief, Pawan Jolly, Vivek Pachauri, Xianping Chen, Pedro Estrela, Sven Ingebrandt

Research output: Contribution to journalArticlepeer-review

15 Citations (SciVal)
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In the field of label-free biosensing, various transducer materials and strategies are under investigation to overcome the Debye-screening limitation of charged biomolecules. We demonstrate an in-line, impedimetric aptasensor with reduced graphene-oxide (rGO) thin films as transducers to detect prostate specific antigens (PSA) in a physiological buffer solution. Unlike classical electrochemical impedance spectroscopy (EIS), this direct, label-free and fully-electronic biosensor approach does not need any redox markers. As specific capture molecules, short anti-PSA aptamers ensured a close binding of the target molecules to the transducer surfaces. Results showed a limit of detection smaller than 33 pM of PSA and a wide detection range from 0.033 to 330 nM fully covering the clinically relevant range of PSA (0.115–0.290 nM). This promising performance can be attributed to the bipolar electronic transport characteristics of the ultra-thin rGO layers similar to pristine graphene. The attachment of target biomolecules to the films changes the resistance of the rGO thin films. Such an in-line EIS configuration with rGO thin films opens promising prospects for biosensing beyond the Debye-screening limitation, which is a major challenge for conventional semiconductor field-effect devices towards clinical applications.

Original languageEnglish
Pages (from-to)352-359
Number of pages8
JournalBiosensors and Bioelectronics
Early online date14 Sept 2018
Publication statusPublished - 1 Apr 2019


  • Aptasensor
  • Debye-screening limitation
  • In-line electrochemical impedance spectroscopy
  • Reduced graphene-oxide thin films

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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