Chiral discrimination between alanine enantiomers by field effect transistor with a homocysteine monolayer-modified gate

Mariko Matsunaga, Daisuke Yamamoto, Takuya Nakanishi, Tetsuya Osaka

Research output: Contribution to journalArticle

18 Citations (Scopus)


The application of field effect transistor (FET) to chiral discrimination was investigated. An Au film vapor-deposited on a self-assembled monolayer (SAM) of (3-mercaptopropyl)trimethoxysilane, which was formed on the SiO2 gate of FET as an adhesive and insulating layer, stabilizes the drain current-gate voltage (Id-Vg) property of FET. The modification by homocysteine (Hcy) SAM on the surface of Au-coated gate makes it possible for the FET to distinguish between the enantiomers of alanine (Ala). Namely, after the sequential addition of Ala and Cu(II) to a K2SO4 solution in this system, it was confirmed that the lateral shift of Id-Vg curves for the FET corresponded to the chirality of Ala. With the l-Hcy SAM-modified gate, a notable negative shift was observed for l-Ala, whereas the shift observed with d-Ala was much smaller. In contrast, opposite results were obtained with d-Hcy SAM. Results of quartz crystal microbalance measurement suggested that such an FET response was originated from the enantioselective formation of diastereomeric Cu complexes with Ala molecules on the Hcy SAM. This system was demonstrated to respond quantitatively to one enantiomeric form of Ala in mixed solutions of two enantiomers as well as in pure enantiomeric solutions.

Original languageEnglish
Pages (from-to)4501-4505
Number of pages5
JournalElectrochimica Acta
Issue number15
Publication statusPublished - 2010 Jun 1



  • Amino acids
  • Chiral discrimination
  • Copper complex
  • Field effect transistor
  • Self-assembled monolayer

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

Cite this