Use of diode lasers in an evanescent wave immunosensor for stationary and time-resolved detection of antigens

✍ Scribed by D. Bock; K. Galla; M. Martin; J. Wolfrum; S. Seeger

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 543 KB
• Volume: 29
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(95)01696-1

✦ Synopsis

A compact and inexpensive fiber-optic evanescent wave immunosensor is presented which uses a diode laser as excitation source both in continuous wave measurements as well as in time-resolved experiments. The continuous wave laser operates at 657 nm utilizing a commercially available dye-conjugated polyclonal antibody. Time-resolved experiments with a diode laser emitting at 674 nm were carried out with two fluorescent dyes, which have nearly identical absorption and emission wavelengths, but differ in their fluorescence lifetimes. This shows the possibility of detecting several molecules simultaneously, which are tagged with so-called 'multiplex dyes', by identifying the different fluorescence lifetimes. Using a new rhodamine dye a successful test of observing the time-resolved binding process between immobilized antibodies and dye-conjugated antigens is reported.