Tailored Magnetic Nanoparticles for Direct and Sensitive Detection of Biomolecules in Biological Samples
2008 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, no 10, 3423-3428 p.Article in journal (Refereed) Published
We developed nanoparticles with tailored magnetic properties for sensitive detection of biomolecules directly in biological samples in a single step. Thermally blocked nanoparticles obtained by thermal hydrolysis 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 events significantly increase 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 Brucella antibodies in serum samples from infected cows and the surface of the nanoparticles was functionalized with lipopolysaccarides (LPS) from Brucella abortus. The hydrodynamic volume of functionalized particles increased by 25-35% as a result of the binding of the antibodies, as measured by changes in the susceptibility in an alternating magnetic field. The method has shown high sensitivity, with detection limit of 7 nmol·L-1 in serum without any pre-treatment of the biological samples.
The detection method is very sensitive, cost-efficient and versatile, giving a direct indication if 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 homogenous assays for a wide range of applications.
Place, publisher, year, edition, pages
2008. Vol. 8, no 10, 3423-3428 p.
BRUCELLA-ABORTUS, RELAXATION, ANTIBODIES, PARTICLES
IdentifiersURN: urn:nbn:se:kth:diva-9231DOI: 10.1021/nl8022498ISI: 000259906800064ScopusID: 2-s2.0-56149116406OAI: oai:DiVA.org:kth-9231DiVA: diva2:37666
QC 201010012008-10-102008-10-102010-12-07Bibliographically approved