title: Optical characterization of the antigen-antibody thin layer using the whispering gallery mode.
abstract: We immobilized an antibody (anti-β-Galactosidase) on a polystyrene microsphere by using a covalent bond, and observed the resonance peaks in the scattered light intensity spectra related to the whispering gallery mode (WGM) excitation of the microsphere. The amount and the optical parameters, i.e., thickness and refractive index, of anti-β-Galactosidase on the sphere surface were evaluated based on an absorbance measurement and a resonance peak shift measurement, respectively. Moreover, we measured the variation of the WGM spectra depending on the concentration of the enzyme solution (β-Galactosidase), which allowed us to optically evaluate the thickness and the refractive index of the antigen-antibody layer from the shift of the WGM spectra peak.
authors.affiliation: Industrial Technology Center of Nagasaki.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tajiri
authors.forename: Shuzo
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Imato
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Okamoto
authors.forename: Masanobu
authors.initials: M
authors.lastname: Haraguchi
mesh_terms: D000937:Antigen-Antibody Reactions; D008863:Microspheres; D055095:Optics and Photonics