title: Shift of whispering-gallery modes in microspheres by protein adsorption.
abstract: Biosensors based on the shift of whispering-gallery modes in microspheres accompanying protein adsorption are described by use of a perturbation theory. For random spatial adsorption, theory predicts that the shift should be inversely proportional to microsphere radius R and proportional to protein surface density and excess polarizability. Measurements are found to be consistent with the theory, and the correspondence enables the average surface area occupied by a single protein to be estimated. These results are consistent with crystallographic data for bovine serum albumin. The theoretical shift for adsorption of a single protein is found to be extremely sensitive to the target region, with adsorption in the most sensitive region varying as 1/R(5/2). Specific parameters for single protein or virus particle detection are predicted.
authors.affiliation: Microparticle Photophysics Lab MP3L), Polytechnic University, Brooklyn, New York 11201, USA. arnold@photon.poly.edu
authors.forename: S
authors.initials: S
authors.lastname: Arnold
authors.forename: M
authors.initials: M
authors.lastname: Khoshsima
authors.forename: I
authors.initials: I
authors.lastname: Teraoka
authors.forename: S
authors.initials: S
authors.lastname: Holler
authors.forename: F
authors.initials: F
authors.lastname: Vollmer
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques; D008863:Microspheres; D008962:Models, Theoretical; D011506:Proteins / Q000493:pharmacokinetics; D012710:Serum Albumin, Bovine / Q000493:pharmacokinetics
chemical_list: D011506:Proteins; D012710:Serum Albumin, Bovine