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High‐power blue/UV light‐emitting diodes as excitation sources for sensitive detection
Author(s) -
Kuo Jason S.,
Kuyper Christopher L.,
Allen Peter B.,
Fiorini Gina S.,
Chiu Daniel T.
Publication year - 2004
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200406118
Subject(s) - fluorescence , light emitting diode , rhodamine 6g , optoelectronics , detection limit , materials science , laser , analyte , capillary electrophoresis , diode , blue laser , analytical chemistry (journal) , chemistry , optics , chromatography , physics
Abstract With advances in III‐V nitride manufacturing processes, high‐power light‐emitting diode (LED) chips in the blue and UV wavelengths are now commercially available at reasonable cost and can be used as excitation sources in optical sensing. We describe the use of these high‐power blue and UV LEDs for sensitive fluorescence detection, including chip‐based flow cytometry, capillary electrophoresis (CE), and single‐molecule imaging. By using a blue LED with a focusable power of ∼40 mW as the excitation source for fluorescent beads, we demonstrate a simple chip‐based bead sorter capable of enriching the concentration of green fluorescent beads from 63% to 95%. In CE experiments, we show that a mixture of analyte solution containing 30 n M 6‐carboxyrhodamine 6G and 10 n M fluorescein can be separated and detected with excellent signal‐to‐noise ratio (∼17 for 10 n M fluorescein) using the collimated emission from a blue LED; the estimated mass detection limit was ∼200 zmol for fluorescein. We also demonstrated ultrasensitive fluorescence imaging of single rhodamine 123 molecules and individual λ‐DNA molecules. At a small fraction of the cost of an Ar + laser, high‐power blue and UV LEDs are effective alternatives for lasers and arc lamps in fluorescence applications that demand portability, low cost, and convenience.