title: Kinetic analyses and performance of a colloidal magnetic nanoparticle based immunoassay dedicated to allergy diagnosis.
abstract: In this paper, we demonstrate the possibility to use magnetic nanoparticles as immunosupports for allergy diagnosis. Most immunoassays used for immunosupports and clinical diagnosis are based on a heterogeneous solid-phase system and suffer from mass-transfer limitation. The nanoparticles' colloidal behavior and magnetic properties bring the advantages of homogeneous immunoassay, i.e., species diffusion, and of heterogeneous immunoassay, i.e., easy separation of the immunocomplex and free forms, as well as analyte preconcentration. We thus developed a colloidal, non-competitive, indirect immunoassay using magnetic core-shell nanoparticles (MCSNP) as immunosupports. The feasibility of such an immunoassay was first demonstrated with a model antibody and described by comparing the immunocapture kinetics using macro (standard microtiter plate), micro (microparticles) and nanosupports (MCSNP). The influence of the nanosupport properties (surface chemistry, antigen density) and of the medium (ionic strength, counter ion nature) on the immunocapture efficiency and specificity was then investigated. The performances of this original MCSNP-based immunoassay were compared with a gold standard enzyme-linked immunosorbent assay (ELISA) using a microtiter plate. The capture rate of target IgG was accelerated 200-fold and a tenfold lower limit of detection was achieved. Finally, the MCSNP-based immunoassay was successfully applied to the detection of specific IgE from milk-allergic patient's sera with a lower LOD and a good agreement (CV < 6%) with the microtiter plate, confirming the great potential of this analytical platform in the field of immunodiagnosis.
authors.affiliation: Physicochimie des Electrolytes, Colloïdes et Sciences Analytiques (PECSA) UMR 7195 CNRS-ESPCI-UPMC, Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Teste
authors.forename: Frédéric
authors.initials: F
authors.lastname: Kanoufi
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Descroix
authors.forename: Pascal
authors.initials: P
authors.lastname: Poncet
authors.forename: Thomas
authors.initials: T
authors.lastname: Georgelin
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Siaugue
authors.forename: Jan
authors.initials: J
authors.lastname: Petr
authors.forename: Anne
authors.initials: A
authors.lastname: Varenne
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Hennion
mesh_terms: D003102:Colloids; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis*; D007118:Immunoassay / Q000379:methods*; D007136:Immunoglobulins / Q000097:blood*; D007700:Kinetics; D057230:Limit of Detection; D008280:Magnetics; D016269:Milk Hypersensitivity / Q000175:diagnosis; D053758:Nanoparticles
chemical_list: D003102:Colloids; D007136:Immunoglobulins