Title :
Evanescent-Wave Spectroscopy Using an SU-8 Waveguide for Rapid Quantitative Detection of Biomolecules
Author :
Jiang, Linan ; Gerhardt, Karl P. ; Myer, Brian ; Zohar, Yitshak ; Pau, Stanley
Author_Institution :
Coll. of Opt. Sci., Arizona Univ., Tucson, AZ
Abstract :
A 30-mm-long multimode waveguide, 40 mum wide and 40 mum high, is fabricated on a silicon wafer using polymer SU-8 as the core and liquid buffer as the cladding. Antibodies are successfully immobilized on the SU-8 surface designated for binding target antigens dispersed in the buffer solution. Evanescent-wave spectroscopy is performed by exciting the fluorescently labeled antigens, bound to the waveguide surface within its evanescence field, and measuring the emission light intensity. This evanescent-wave biosensor detects specific molecular interaction. The optical output as a function of the antigen concentration can be described by Langmuir equation. Antigen concentration as low as 1.5 mug/mL is detected; concentrations higher than 100 mug/mL lead to sensor saturation.
Keywords :
biochemistry; biosensors; chemical variables measurement; fluorescence; molecular biophysics; optical planar waveguides; optical polymers; proteins; silicon; Langmuir equation; Si; antibodies immobilization; antigen concentration detection; cladding; emission light intensity; evanescence field; evanescent-wave biosensor; evanescent-wave spectroscopy; fluorescently labeled antigens; liquid buffer; multimode waveguide fabrication; optical output; polymer SU-8 waveguide surface; rapid quantitative biomolecule detection; silicon wafer; size 30 mm; size 40 mum; specific molecular interaction detection; surface-associated phenomena; target antigens binding; Antibody immobilization; SU-8 waveguide; biomolecule binding; evanescent wave;
Journal_Title :
Microelectromechanical Systems, Journal of
DOI :
10.1109/JMEMS.2008.2006814
