title: Full on-chip nanoliter immunoassay by geometrical magnetic trapping of nanoparticle chains.
abstract: We propose an original concept to perform a complete on-chip sandwich immunoassay on magnetic nanoparticles that are self-assembled in chains in a uniform magnetic field. The magnetic chains are retained over periodically enlarged cross sections of a microfluidic channel. Thereby they strongly interact with the flow and rapidly capture the total of a low number of target molecules from nanoliter sample volumes. As an example, we demonstrate the detection of murine monoclonal antibodies in a noncompetitive sandwich immunoassay with a detection limit of 1 ng mL(-1) in nanoliters of hybridoma cell culture medium.
authors.affiliation: Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lacharme
authors.forename: Caroline
authors.initials: C
authors.lastname: Vandevyver
authors.forename: Martin A M
authors.initials: MA
authors.lastname: Gijs
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D001710:Biotin / Q000737:chemistry; D002478:Cells, Cultured; D006825:Hybridomas; D007118:Immunoassay / Q000379:methods*; D008280:Magnetics; D051379:Mice; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D019809:Streptavidin / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D001710:Biotin; D019809:Streptavidin