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

Abstract

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
Volume9
Issue number44
DOIs
StatePublished - Nov 8 2017

Bibliographical note

Funding Information:
This work was supported by the Minnesota Partnership for Biotechnology and Medical Genomics Decade of Discovery in Diabetes Program and the Alice M. O’Brien Foundation. Device fabrication was performed at the Minnesota Nano-fabrication Center at the University of Minnesota, which receives partial support from the National Science Foundation (NSF) through the National Nanotechnology Coordinated Infrastructure under Award ECCS-1542202. Portions of this work were also carried out in the University of Minnesota Characterization Facility, which received capital equipment funding from the University of Minnesota MRSEC under NSF Award DMR-1420013.

Publisher Copyright:
© 2017 American Chemical Society.

Keywords

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

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