title: Analysis of wavelength shift versus surface coverage of proteins on nano-porous silicon immunosensor.
abstract: The Fabry-Perot fringe pattern is determined by wavelength shifts in interferometric reflectance spectroscopy, which is a function of the refractive index (n) and thickness (l) of the porous silicon (PSi). In this paper, we demonstrated the shifts of wavelength as systematic controlling of adsorbed concentration of a protein on the PSi substrate. In order to correlate the wavelength shift of the Fabry-Perot fringe pattern with the protein adsorption, adsorbed concentrations of avidin (66 kDa) on the PSi substrate were measured by three independent methods: first, by means of bromophenol blue, which is applied to surface-confined avidin; second, with fluorescence intensity measurement of FITC-tagged avidin; and finally by utilizing Time of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS). It was found that the wavelength shift is directly proportional to the surface-adsorbed avidins over the wide range of surface concentration on the PSi substrate, with a rate of 0.1 nm red-shift at avidin concentration change of 1.0 fmol/cm2.
authors.affiliation: Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea.
authors.forename: Hyo-Sop
authors.initials: HS
authors.lastname: Kim
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Kim
authors.forename: SooSuk
authors.initials: S
authors.lastname: Lee
authors.forename: Sung-Wook
authors.initials: SW
authors.lastname: Choi
authors.forename: Kwangnak
authors.initials: K
authors.lastname: Koh
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Kim
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D016062:Porosity; D040081:Protein Array Analysis / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*; D012825:Silicon / Q000737:chemistry*
chemical_list: D012825:Silicon