Development of a Fiber-Optic Capillary Evanescent Wave Surface Plasmon Resonance Biosensor

• Main Authors: Brian K. KELLER, Olga SHULGA, Christopher P. PALMER, Michael D. DEGRANDPRE
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2008-02-01
• Series: Sensors & Transducers
• Subjects: fiber-optic capillary; capillary waveguide; surface plasmon resonance; fiber-optic biosensor
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/february_08/P_235.pdf

Development of a surface plasmon resonance (SPR) FOCap (fiber-optic capillary) sensor for bulk and localized refractive index measurements is reported. The FOCap supports multimode light propagation within the capillary wall. An evanescent field, protruding from the capillary wall and into the core, is attenuated by interacting with the surface plasmon oscillations from gold nanoparticles (AuNPs) that are covalently immobilized within the capillary. The FOCap design allows for long pathlength evanescent sensing. The response of the FOCap SPR sensor to bulk refractive index solutions is tested and the optical properties are discussed. The device may also function as a localized refractive index biosensor. Development of a protein-specific biosensor is ongoing but proof-of-concept is confirmed by a non-specific interaction between fibrinogen and a self-assembled monolayer (SAM) covering the AuNP surface. In the future, the FOCap SPR sensor will be tested for sensitivity with biotin-streptavidin affinity and protein specificity will be demonstrated by antibody/antigen affinity interactions. Ultimately this easy-to-assemble SPR biosensor could be utilized in routine protein assays.