Non-contact photothermal control of enzyme reactions on a microchip by using a compact diode laser

Yuki Tanaka, Maxim N. Slyadnev, Akihide Hibara, Manabu Tokeshi, Takehiko Kitamori

Research output: Contribution to journalArticlepeer-review

87 Citations (Scopus)


Photothermal temperature control of an enzyme-catalyzed reaction in a microchip using a diode laser was demonstrated. A laser beam with energy of 10 mW was used to irradiate an absorbing target placed on top of the microchip cover plate. Theoretical calculations have shown that temperature in the microchannel can be locally increased by 5-7°C during short time intervals, due to heat released by the target. The rate of the enzyme reaction, which was initially inhibited due to cooling of the chip to low temperature, was increased when the target was irradiated. The products were detected by a thermal lens microscope. The product concentration was shown to depend on irradiation time, laser intensity and substrate concentration. Reaction characteristics (rate constant of the reaction) were then derived from these dependencies. The reaction volume and absolute quantity of the reaction product were estimated as 10 nl and 100 fmol, respectively. It was also demonstrated that a direct solvent heating method using infrared radiation could control the reaction in the microchannel. (C) 2000 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)45-51
Number of pages7
JournalJournal of Chromatography A
Issue number1-2
Publication statusPublished - 2000 Oct 13
Externally publishedYes


  • Diaminobenzidine tetrahydrochloride
  • Enzymes
  • Hydrogen peroxide
  • Instrumentation
  • Microchannels
  • Microchips
  • Peroxidases
  • Thermal lens detection

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry


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