Analysis of wavelength shift versus surface coverage of proteins on nano-porous silicon immunosensor.
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.
Kim
Hyo-Sop
HS
Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea.
Kim
Jin-Ho
JH
Lee
SooSuk
S
Choi
Sung-Wook
SW
Koh
Kwangnak
K
Kim
Jae-Ho
JH
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*
D012825:Silicon