Tailored Magnetic Nanoparticles for Direct and Sensitive Detection of Biomolecules in Biological Samples
Artikel i vetenskaplig tidskrift, 2008

We developed nanoparticles with tailored magnetic properties for direct and sensitive detection of biomolecules in biological samples in a single step. Thermally blocked nanoparticles obtained by thermal hydrolysis, functionalized with specific ligands, are mixed with sample solutions, and the variation of the magnetic relaxation due to surface binding is used to detect the presence of biomolecules. The binding significantly increases the hydrodynamic volume of nanoparticles, thus changing their Brownian relaxation frequency which is measured by a specifically developed AC susceptometer, The system was tested for the presence of Brucelia antibodies, a dangerous pathogen causing brucellosis with severe effects both on humans and animals, in serum samples from infected cows and the surface of the nanoparticles was functionalized with lipopolysaccarides (LPS) from Brucella abortus. The hydrodynamic volume of LPS-functionalized particles increased by 25-35% as a result of the binding of the antibodies, measured by changes in the susceptibility in an alternating magnetic field. The method has shown high sensitivity, with detection limit of 0.05 mu g.mL(-1) of antibody in the biological samples without any pretreatment. This magnetic-based assay is very sensitive, cost-efficient, and versatile, giving a direct indication whether the animal is infected or not, making it suitable for point-of-care applications. The functionalization of tailored magnetic nanoparticles can be modified to suit numerous homogeneous assays for a wide range of applications.

PARTICLES

RELAXATION

ANTIBODIES

BRUCELLA-ABORTUS

Författare

A. Fornara

Kungliga Tekniska Högskolan (KTH)

P. Johansson

Imego AB - The Institute of Micro and Nanotechnology

K. Petersson

Imego AB - The Institute of Micro and Nanotechnology

Stefan Gustafsson

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

SuMo Biomaterials

J. Qin

Kungliga Tekniska Högskolan (KTH)

Eva Olsson

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

D. Ilver

Imego AB - The Institute of Micro and Nanotechnology

A. Krozer

Imego AB - The Institute of Micro and Nanotechnology

M. Muhammed

Kungliga Tekniska Högskolan (KTH)

C. Johansson

Kungliga Tekniska Högskolan (KTH)

Nano Letters

1530-6984 (ISSN) 1530-6992 (eISSN)

Vol. 8 3423-3428

Ämneskategorier

Annan teknik

DOI

10.1021/nl8022498