title: Differential spectral phase interferometry for wide dynamic range surface plasmon resonance biosensing.
abstract: We introduce a novel wide dynamic range phase-sensitive surface plasmon resonance (SPR) biosensor based on differential spectral interferometry. Superseding conventional spectroscopic approach where only the SPR dip is monitored, our system acquires the spectral phase information of the entire electromagnetic field that undergoes SPR transformation. Since the SPR-induced phase change is highly wavelength specific with fixed incident angle, ultra-high sensitivity achievable through phase-sensitive detection, as reported herein, is maintained continuously across the spectral domain in response to refractive index changes. Our system has demonstrated a detection limit of 2.2×10(-7) in terms of refractive index unit (RIU) using standard single-layer gold surface. In terms of biosensing performance, the estimated detection sensitivity obtained from bovine serum albumin (BSA) antibody-antigen binding experiments is 0.5 ng ml(-1).
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, PR China.
authors.forename: Siu-Pang
authors.initials: SP
authors.lastname: Ng
authors.forename: Chi-Man Lawrence
authors.initials: CM
authors.lastname: Wu
authors.forename: Shu-Yuen
authors.initials: SY
authors.lastname: Wu
authors.forename: Ho-Pui
authors.initials: HP
authors.lastname: Ho
authors.forename: S K
authors.initials: SK
authors.lastname: Kong
mesh_terms: D000818:Animals; D000937:Antigen-Antibody Reactions; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D002417:Cattle; D058266:Dielectric Spectroscopy / Q000295:instrumentation / Q000379:methods*; D006046:Gold; D066298:In Vitro Techniques; D007368:Interferometry / Q000295:instrumentation / Q000379:methods*; D057230:Limit of Detection; D012031:Refractometry; D012710:Serum Albumin, Bovine / Q000276:immunology / Q000378:metabolism; D020349:Surface Plasmon Resonance / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data
chemical_list: D012710:Serum Albumin, Bovine; D006046:Gold