title: Highly sensitive differential phase-sensitive surface plasmon resonance biosensor based on the Mach-Zehnder configuration.
abstract: A high-sensitivity surface plasmon resonance (SPR) biosensor based on the Mach-Zehnder interferometer design is presented. The novel feature of the new design is the use of a Wollaston prism through which the phase quantities of the p and s polarizations are interrogated simultaneously. Since SPR affects only the p polarization, the signal due to the s polarization can be used as the reference. Consequently, the differential phase between the two polarizations allows us to eliminate all common-path phase noise while keeping the phase change caused by the SPR effect. Experimental results obtained from glycerin-water mixtures indicate that the sensitivity limit of our scheme is 5.5 x 10(-8) refractive-index units per 0.01 degrees phase change. To our knowledge, this is a significant improvement over previously obtained results when gold was used as the sensor surface. Such an improvement in the sensitivity limit should allow SPR biosensors to become a possible replacement for conventional biosensing techniques based on fluorescence. Monitoring of the bovine serum albumin (BSA) binding reaction with BSA antibodies is also demonstrated.
authors.affiliation: Center for Advanced Research in Photonics, Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: S Y
authors.initials: SY
authors.lastname: Wu
authors.forename: H P
authors.initials: HP
authors.lastname: Ho
authors.forename: W C
authors.initials: WC
authors.lastname: Law
authors.forename: Chinlon
authors.initials: C
authors.lastname: Lin
authors.forename: S K
authors.initials: SK
authors.lastname: Kong
mesh_terms: D000936:Antigen-Antibody Complex / Q000032:analysis* / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D045424:Complex Mixtures / Q000032:analysis; D005240:Feasibility Studies; D005990:Glycerol / Q000032:analysis; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D007368:Interferometry / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000032:analysis* / Q000276:immunology; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods; D014159:Transducers; D014867:Water / Q000032:analysis
chemical_list: D000936:Antigen-Antibody Complex; D045424:Complex Mixtures; D014867:Water; D012710:Serum Albumin, Bovine; D005990:Glycerol