title: Wide dynamic range phase-sensitive surface plasmon resonance biosensor based on measuring the modulation harmonics.
abstract: In this study, a novel phase-sensitive surface plasmon resonance (SPR) setup, based on temporal modulation of a pumping beam by a photoelastic modulator, and subsequent extraction of phase information at the second and the third harmonics of the modulation frequency, has been developed to study biomolecular interactions on SPR-supporting gold. We demonstrated that the design setup provides ultra-high phase sensitivity, together with a wide dynamic range of measurements. In particular, the proposed scheme was used to study real-time interaction of biotin-protein and streptavidin-BSA complexes. We have found that the proposed technique has a detection limit as high as 2.89 x 10(-7) in terms of refractive index units (RIU). In terms of biosensing performance, a detection sensitivity of 1.3 nM from the streptavidin-maleimide/thiolated BSA complex binding reaction has also been demonstrated.
authors.affiliation: Institute for Lasers, Photonics and Biophotonics, Departments of Electrical Engineering, State University of New York at Buffalo, Buffalo, NY 14260, USA.
authors.forename: Wing-Cheung
authors.initials: WC
authors.lastname: Law
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Markowicz
authors.forename: Ken-Tye
authors.initials: KT
authors.lastname: Yong
authors.forename: Indrajit
authors.initials: I
authors.lastname: Roy
authors.forename: Alexander
authors.initials: A
authors.lastname: Baev
authors.forename: Sergiy
authors.initials: S
authors.lastname: Patskovsky
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Kabashin
authors.forename: Ho-Pui
authors.initials: HP
authors.lastname: Ho
authors.forename: Paras N
authors.initials: PN
authors.lastname: Prasad
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D001710:Biotin / Q000032:analysis / Q000378:metabolism; D002417:Cattle; D004563:Electrochemistry; D012031:Refractometry / Q000295:instrumentation; D012710:Serum Albumin, Bovine / Q000032:analysis / Q000378:metabolism; D019809:Streptavidin / Q000032:analysis / Q000378:metabolism; D020349:Surface Plasmon Resonance / Q000295:instrumentation*