Optical Detection of Enzymatic Activity and Inhibitors on Non-Covalently Functionalized Fluorescent Graphene Oxide

Tae Woog Kang, Su Ji Jeon, Hye In Kim, Jung Hyun Park, Dabin Yim, Hye Rim Lee, Jong Min Ju, Man Jin Kim, Jong Ho Kim

Research output: Contribution to journalArticlepeer-review


It has been of great interest to measure the activity of acetylcholinesterase (AChE) and its inhibitor, as AChE is known to accelerate the aggregation of the amyloid beta peptides that underlie Alzheimers disease. Herein, we report the development of graphene oxide (GO) fluorescence-based biosensors for the detection of AChE activity and AChE inhibitors. To this end, GO was non-covalently functionalized with phenoxy-modified dextran (PhO-dex-GO) through hydrophobic interaction; the resulting GO showed excellent colloidal stability and intense fluorescence in various aqueous solutions as compared to pristine GO and the GO covalently functionalized with dextran. The fluorescence of PhO-dex-GO remarkably increased as AChE catalyzed the hydrolysis of acetylthiocholine (ATCh) to give thiocholine and acetic acid. It was found that the turn-on fluorescence response of PhO-dex-GO to AChE activity was induced by protonation of carboxyl groups on it from the product of the enzymatic hydrolysis reaction, acetic acid. On the basis of its turn-on fluorescence response, PhO-dex-GO was able to report kinetic and thermodynamic parameters involving a maximum velocity, a Michaelis constant, and an inhibition dissociation constant for AChE activity and inhibition. These parameters enable us to determine the activity of AChE and the efficiency of the inhibitor.

Original languageEnglish (US)
Pages (from-to)5346-5353
Number of pages8
JournalACS Nano
Issue number5
StatePublished - May 24 2016
Externally publishedYes


  • acetylcholinesterase
  • GO fluorescence
  • graphene oxide
  • inhibitor detection
  • optical biosensor

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


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