title: Replacement-free mass-amplified sandwich assay with 180-MHz electrodeless quartz-crystal microbalance biosensor.
abstract: This study describes a sensitivity-amplified detection method in a replacement-free electrodeless quartz-crystal microbalance (QCM) biosensor. A sandwich assay is proposed for detecting C-reactive proteins (CRP), where the biotinated second anti-CRP antibody is weighted by streptavidin for sensitivity amplification. Because the first CRP antibody was immobilized nonspecifically on naked quartz surfaces, the sandwich assay was repeated using the same sensor chip, making possible the replacement-free assay. The mass-amplified sandwich assay detected a CRP solution of 0.1 ng/ml. A methodology for determining the molecular mass of the injected protein is also proposed.
authors.affiliation: Graduate School of Engineering Science, Osaka University, Machikaneyama 1-3, Toyonaka, Osaka 560-8531, Japan. ogi@me.es.osaka-u.ac.jp
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ogi
authors.forename: Taiji
authors.initials: T
authors.lastname: Yanagida
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hirao
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Nishiyama
mesh_terms: D055910:Antibodies, Immobilized / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D002097:C-Reactive Protein / Q000032:analysis* / Q000276:immunology; D007118:Immunoassay / Q000379:methods; D058525:Quartz Crystal Microbalance Techniques / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D055910:Antibodies, Immobilized; D002097:C-Reactive Protein