title: A label-free immunosensor array using single-chain antibody fragments.
abstract: We report a microcantilever-based immunosensor operated in static deflection mode with a performance comparable with surface plasmon resonance, using single-chain Fv (scFv) antibody fragments as receptor molecules. As a model system scFv fragments with specificity to two different antigens were applied. We introduced a cysteine residue at the C terminus of each scFv construct to allow covalent attachment to gold-coated sensor interfaces in directed orientation. Application of an array enabled simultaneous deflection measurements of sensing and reference cantilevers. The differential deflection signal revealed specific antigen binding and was proportional to the antigen concentration in solution. Using small, oriented scFv fragments as receptor molecules we increased the sensitivity of microcantilevers to approximately 1 nM.
authors.affiliation: National Center of Competence in Research for Nanoscience, Institute of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
authors.forename: Natalija
authors.initials: N
authors.lastname: Backmann
authors.forename: Christian
authors.initials: C
authors.lastname: Zahnd
authors.forename: Francois
authors.initials: F
authors.lastname: Huber
authors.forename: Alexander
authors.initials: A
authors.lastname: Bietsch
authors.forename: Andreas
authors.initials: A
authors.lastname: Plückthun
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Lang
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Güntherodt
authors.forename: Martin
authors.initials: M
authors.lastname: Hegner
authors.forename: Christoph
authors.initials: C
authors.lastname: Gerber
mesh_terms: D000941:Antigens / Q000378:metabolism*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D007128:Immunoglobulin Fragments / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000941:Antigens; D007128:Immunoglobulin Fragments