Low-cost, transparent, and flexible single-walled carbon nanotube nanocomposite based ion-sensitive field-effect transistors for pH/glucose sensing

Dongjin Lee, Tianhong Cui

Research output: Contribution to journalArticle

72 Scopus citations

Abstract

Low-cost, transparent, and flexible ion-sensitive field-effect transistors (ISFETs) are presented as pH and glucose sensors. Single-walled carbon nanotubes (SWCNTs) and poly(diallyldimethyammonium chloride, PDDA) are deposited by layer-by-layer (LbL) self-assembly between two metallic electrodes patterned on a polyethylene terephthalate substrate. The pH ISFETs are characterized based on the fact that the electronic conductance of SWCNTs nanocomposite is determined by molecular protonation/deprotonation of carboxylic groups on SWCNTs and by the external Ag/AgCl reference gate voltage. Glucose is detected by the local pH change in the vicinity of SWCNTs with the aid of glucose oxidase (GOx) enzyme. The glucose sensor shows a sensitivity of 18-45μA/mM on a linear range of 2-10. mM. The apparent Michaelis-Menten constant is 14.2. mM, indicating a high affinity of LbL assembled GOx to glucose. The LbL self-assembly of nanomaterials and enzymes on the transparent and flexible substrate suggests various chemical and biological sensors suitable for in vivo application.

Original languageEnglish (US)
Pages (from-to)2259-2264
Number of pages6
JournalBiosensors and Bioelectronics
Volume25
Issue number10
DOIs
StatePublished - Jun 1 2010

Keywords

  • Carbon nanotube
  • Flexible sensor
  • Glucose sensor
  • ISFET
  • Layer-by-layer self-assembly
  • PH sensor

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