Highly sensitive differential phase-sensitive surface plasmon resonance biosensor based on the Mach-Zehnder configuration.
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.
Wu
S Y
SY
Center for Advanced Research in Photonics, Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China.
Ho
H P
HP
Law
W C
WC
Lin
Chinlon
C
Kong
S K
SK
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
D000936:Antigen-Antibody Complex; D045424:Complex Mixtures; D014867:Water; D012710:Serum Albumin, Bovine; D005990:Glycerol