Capacitive Sensing of Glucose in Electrolytes Using Graphene Quantum Capacitance Varactors

Yao Zhang, Rui Ma, Xue V. Zhen, Yogish C. Kudva, Philippe Bühlmann, Steven J. Koester

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


A novel graphene-based variable capacitor (varactor) that senses glucose based on the quantum capacitance effect was successfully developed. The sensor utilizes a metal-oxide-graphene varactor device structure that is inherently compatible with passive wireless sensing, a key advantage for in vivo glucose sensing. The graphene varactors were functionalized with pyrene-1-boronic acid (PBA) by self-assembly driven by π-π interactions. Successful surface functionalization was confirmed by both Raman spectroscopy and capacitance-voltage characterization of the devices. Through glucose binding to the PBA, the glucose concentration in the buffer solutions modulates the level of electrostatic doping of the graphene surface to different degrees, which leads to capacitance changes and Dirac voltage shifts. These responses to the glucose concentration were shown to be reproducible and reversible over multiple measurement cycles, suggesting promise for eventual use in wireless glucose monitoring.

Original languageEnglish (US)
Pages (from-to)38863-38869
Number of pages7
JournalACS Applied Materials and Interfaces
Issue number44
StatePublished - Nov 8 2017


  • glucose
  • graphene
  • label-free biosensing
  • pyrene-1-boronic acid
  • varactor

ASJC Scopus subject areas

  • General Materials Science


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