Nanochannels on a fused-silica microchip and liquid properties investigation by time-resolved fluorescence measurements

Akihide Hibara, Takumi Saito, Haeng Boo Kim, Manabu Tokeshi, Takeshi Ooi, Masayuki Nakao, Takehiko Kitamori

Research output: Contribution to journalArticle

197 Citations (Scopus)

Abstract

We have fabricated nanometer-sized channels, demonstrated a technique for the introduction of liquid into the channels, and carried out time-resolved fluorescence measurements of aqueous solutions. In this study, 330-nm- and 850-nm-sized channels were fabricated on fusedsilica substrates by fast atom beam etching and hydrofluoric acid bonding methods. A liquid introduction method utilizing capillary action was demonstrated. The liquid introduction was observed under an optical microscope, and the liquid velocity during the introduction was analyzed by surface energy and macroscale hydrodynamics. The liquid velocity due to capillary action in the nanometer-sized channel seemed more than four times slower than the estimation. Then, aqueous solutions of rhodamine 6G (R6G), sulforhodamine 101 (SR101), and rhodamine B (RB) in the channels were measured by time-resolved fluorescence spectroscopy; spectra of the same solution in a 250-μm-sized channel were also measured as a reference for the macrospace. Although the fluorescence spectra in the 330-nm-, 850-nm- and 250-μm-sized channels agreed with one another, the fluorescent decays in the nanometer-sized channels were faster for R6G and SR101 and slower for RB than the respective decays in the 250-μm-sized channels. The results suggested the solutions had lower dielectric constants and higher viscosities in the nanometer-sized channels.

Original languageEnglish
Pages (from-to)6170-6176
Number of pages7
JournalAnalytical Chemistry
Volume74
Issue number24
DOIs
Publication statusPublished - 2002 Dec 15
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry

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