Terahertz chemical microscope for label-free detection of protein complex

Toshihiko Kiwa, Yousuke Kondo, Yuji Minami, Iwao Kawayama, Masayoshi Tonouchi, Keiji Tsukada

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


A terahertz (THz) chemical microscope (TCM) has been proposed and developed for label-free analysis of the interactions of proteins, including immune reactions. A SiO2/Si/sapphire plate was fabricated and emitted THz pulses from the sapphire side using a femtosecond laser. The amplitude of a THz pulse depends on the chemical potential of the SiO2 surface. As an initial demonstration, a biotin-avidin complex was analyzed using TCM. Results indicate that biotin concentrations of up to 10-12 mol/l could be detected, suggesting that a high sensitivity immunoassay system can be realized using this method. The distribution of the THz peak amplitude was measured, reflecting the distribution of the biotin-avidin complex on the plate.

Original languageEnglish
Article number211114
JournalApplied Physics Letters
Issue number21
Publication statusPublished - May 24 2010

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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