269 Dual Optical Fiber Total Internal Reflection Fluorescence Spectrometry as a Single Molecular Detection Technique

Thursday, November 5, 2009: 12:00 PM
Rio Grande (Camino Real Hotel)
Shiquan Tao , Deppartment of Mathematics, Chemistry & Physics, West Texas A&M University, Canyon, TX
Lucas Wieck , Deppartment of Mathematics, Chemistry & Physics, West Texas A&M University, Canyon, TX
Anh Quach , Deppartment of Mathematics, Chemistry & Physics, West Texas A&M University, Canyon, TX
Oluwayemi Awoniyi , Deppartment of Mathematics, Chemistry & Physics, West Texas A&M University, Canyon, TX
Total internal reflection fluorescence (TIRF) spectroscopy is a new fluorescence technology.  In TIRF, interference of excitation light on fluorescence detection is avoided because the analyte is excited by the evanescent wave (EW) of light within a waveguide.  Due to the low noise level, present TIRF microscopic technologies have the capability of detecting even a single molecule, and are used in medical, environmental and life science research. However, present TIRF microscopes are complex and expensive, require great care in handling and operation, and are challenging to calibrate for quantitative applications.  The EW of light guided inside an optical fiber can excite an FL compound in the cladding layer of the fiber to emit FL photons.  However, it is inconvenient in a traditional microscopic setting to efficiently collect the FL photons emitted from the surface of an optical fiber.  In this paper, we report an innovative dual optical fiber total internal reflection fluorescence spectrometry (DOF-TIRF) as a highly sensitive detection technology.  Theoretical analysis indicates that DOF-TIRF has the capability of detecting a single molecule existing in the EW filed of an optical fiber.   Compared with present TIRF microscopic technologies, the advantages of this new DOF- TIRF include simple structure, robust, low cost, easy to operate, and feasibility of continuous aqueous solution monitoring. In addition, the surface of the excitation fiber can be modified to trap analyte compounds, which can significantly expand the application of DOF-TIRF technology.  Potential applications of this DOF-TIRF in food safety monitoring and disease diagnosis/screening will be discussed.