A label-free immunosensor array using single-chain antibody fragments.
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.
Backmann
Natalija
N
National Center of Competence in Research for Nanoscience, Institute of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
Zahnd
Christian
C
Huber
Francois
F
Bietsch
Alexander
A
Plückthun
Andreas
A
Lang
Hans-Peter
HP
Güntherodt
Hans-Joachim
HJ
Hegner
Martin
M
Gerber
Christoph
C
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*
D000941:Antigens; D007128:Immunoglobulin Fragments