AVS 52nd International Symposium
    Magnetic Interfaces and Nanostructures Friday Sessions
       Session MI+BI-FrM

Paper MI+BI-FrM5
Synthesis and Surface Engineering of Superparamagnetic Nanoparticles

Friday, November 4, 2005, 9:40 am, Room 204

Session: Biosensors and Biomagnetism
Presenter: R. De Palma, IMEC vzw, Belgium
Authors: R. De Palma, IMEC vzw, Belgium
S. Peeters, IMEC vzw, Belgium
K. Bonroy, IMEC vzw, Belgium
G. Reekmans, IMEC vzw, Belgium
F. Frederix, IMEC vzw, Belgium
W. Laureyn, IMEC vzw, Belgium
G. Borghs, IMEC vzw, Belgium
C. Van Hoof, IMEC vzw, Belgium
G. Maes, KULeuven, Belgium
Correspondent: Click to Email
Superparamagnetic nanoparticles with appropriate surface chemistry have been widely used for numerous applications such as MRI, hyperthermia treatment, magnetic biosensing, etc. These applications require that the nanoparticles have high magnetization values, a well-defined and controllable morphology and an overall uniform size distribution. In addition, these applications need special (bio)chemical functionalisation of the magnetic nanoparticles, specifically tuned towards their demands. Most work has been done in improving the quality of magnetic nanoparticles, but only a few scientific investigations have been carried out in engineering and improving their (bio)chemical surface characteristics. Here we present several approaches, to engineer the surface characteristics of superparamagnetic nanoparticles, without altering their magnetic and morphological characteristics. Monodisperse superparamagnetic nanoparticles with controllable size, shape and magnetic properties were synthesized based on the thermal decomposition method. The chemical functionality of these nanoparticles could be tuned by the covalent attachment of thin silane SAMs on the particle surface. An optimized procedure allowed the controllable deposition of high quality silane SAMs with different endgroups. By these means, the nanoparticles could be made water-soluble and capable to covalently couple biological receptors. Several receptors were successfully immobilized onto magnetic nanoparticles, while retaining their biological activity. The degree of receptor immobilization was determined to be 2-10 times higher, compared to 2D substrates. The synthesized magnetic nanoparticles were also coated with a thin shell of inorganic material such as Au and SiO@sub 2@ based on a novel and straightforward coating procedure. The superparamagnetic nanoparticles were characterised using TEM, XRD, FTIR, XPS, UV/vis, SQUID and Bradford.