Publications
Multiparametric magnetic immunoassays utilizing non-linear signatures of magnetic labels
Lenglet L. Journal of Magnetism and Magnetic Materials, 2009, 104.
Résumé. A powerful route to utilizing magnetic nanoparticles as labels in magnetic immunoassays is to exploit their non-linear response when they are exposed to a multi-frequency alternating magnetic field. We have upgraded this non-linear method allowing for the detection, discrimination and quantification of particles of two kinds when mixed together, with no need for spatial resolution. Each kind of particle is characterized by a specific magnetic signature based on d2B(H)/dH2. Appropriate data processing of the signature measured on a mixture of both particles allows for obtaining the amount of each particle. This will enable utilizing magnetic labels for multiparametric magnetic immunoassays.
Highly sensitive room-temperature method of non-invasive in vivo detection of magnetic nanoparticles
Nikitin M.P. et al. Journal of Magnetism and Magnetic Materials, 2009.
Résumé. Methods of non-invasive in vivo quantification of magnetic nanoparticles (MP) have been proposed and realized. The methods are based on non-linear MP magnetization at two frequencies and measuring the response at combinatorial frequencies. The first method is developed for real-time study of MP dynamics and their clearance from the blood system of animals. High sensitivity of 3 ng of Fe3O4 in 0.1 ml was achieved for MP detection in mice tail veins. The second technique is proposed for MP detection inside animal tissues by an external probe. The proposed methods could essentially widen capabilities of biomedical research which involves magnetic nanoparticles.
Characterization of magnetic labels for bioassays
Lalatonne Y. et al. Journal of Magnetism and Magnetic Materials, 2009.
Résumé. Magnetic nanoparticles differing by their size have been synthesized to use them for multiparametric testing, based on their differing magnetic properties. The nanoparticle has two essential roles: to act as a probe owing to its specific magnetic properties and to carry on its surface precursor groups for the covalent coupling of biological recognition molecules, such as antibodies, nucleic acids.
A totally unique, newly patented, method has been used to characterize magnetic signatures using the MIAplex technology. The MIAplex reader, developed by Magnisense, measures the non linear response of the magnetic labels when they are exposed to a multi-frequency alternating magnetic field. This specific signature based on d2B(H)/dH2 was correlated to other more conventional magnetic detection methods (SQUID & Mössbauer).
Magnetic immunoassays: A new paradigm in POC
Lenglet L., Nikitin P.I., Péquignot C. IVD Technology, July/August 2008.
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Magnetic Immunoassays
Nikitin P.I. et al. Sensor Letters, 2007, 5, 1, 296-9.
Résumé. New low-noise detection method has been developed and used for
design of a new type of biosensors based on detection of nano-sized superparamagnetic
particles or magnetic beads that serve as labels for biochemical reactions.
The method is based on non-linear magnetization of such particles. The
particles are exposed to a magnetic field having components at two frequencies
f1 and f2. The response is measured at combinatorial frequencies fi =
m · f1 + n · f2, where m and n are integers (one of them
can be zero). The integers can be varied to get the best signal-to-noise
ratio, e.g., fi = f1 ±2 · f2. Several readers have been designed
for the particles counting and used for different immunoassay formats,
including those compatible with immunoconcentration and magnetic enrichment
of antigens. Registration of 0.1 ng/ml of Y. pestis antigen and 103 cell/ml
of Salmonella typhimurium has been demonstrated. The developed biosensing
platforms can be used for medical diagnostics, points of care, food pathogen
detection, water analysis, etc.
New type of biosensor based on magnetic nanoparticle detection
Nikitin P.I. et al. Journal of Magnetism and Magnetic Materials, 2007, 311, 445-9.
Résumé. A new type of biosensor has been developed based on detection
of nanosized superparamagnetic particles that serve as labels in bioreactions.
The method is based on non-linear magnetic material detection by a magnetic
field having components at two frequencies f1 and f2. The response is
measured at the combinatorial frequencies fi = mf1+nf2, where m and n
are integers, e.g., fi = f1 ± f2. Several highly sensitive readers of
superparamagnetic particles have been designed and used for development
of development of various formats of immunoassays, including those compatible
with immunoconcentration and magnetic enrichment of antigen.