| Zugriffsnummer | 19178 |
| Dokumenttyp | Zeitschriftenartikel |
| Sprache | Englisch |
| Titel | Aggregation behaviour of magnetic nanoparticle suspensions investigated by magnetorelaxometry |
| Autor(in); Institution |
Eberbeck, Dietmar; 8.2, Biosignale, PTB-Berlin
Wiekhorst, Frank; 8.2, Biosignale, PTB-Berlin
Steinhoff, Uwe; 8.2, Biosignale, PTB-Berlin
Trahms, Lutz; 8.2, Biosignale, PTB-Berlin
|
| Quelle/Jahr | Journal of Physics: Condensed Matter: 18 (2006), S2829 - S2846 |
| ISSN | 0953-8984 (PRINT) ; 1361-648X (ONLINE) |
| DOI | |
| URL | |
| Verlag | Bristol: Institute of Physics Publishing |
| Freie Schlagworte | Magnetic Nanoparticle ; Magnetorelaxometry ; Aggregation |
| Zusammenfassung | The aggregation behaviour of magnetic nanoparticles is a decisive factor for their application in medicine and biotechnology. We extended the moment superposition model developed ear-lier for describing the Néel relaxation of an ensemble of immobilized particles with a given size distribution by including the Brownian relaxation mechanism. The resulting cluster mo-ment superposition model is used to characterize the aggregation of magnetic nanoparticles in various suspensions in terms of mean cluster size, aggregate fraction, and size dispersion. In stable ferrofluids, we found that 50%...80% of larger magnetic nanoparticles are organised in dimers and trimers. The scaling of the relaxation curves with respect to MNP concentration is found to be a sensitive indicator of the tendency of a MNP suspension to form large aggre-gates, which may limit the biocompatibility of the preparation. Scaling violation was observed in aged water based ferrofluids, and may originate from damaged MNP shells. In biological media such as fetal calf serum, bovine serum albumin, and human serum we observed an ag-gregation behaviour which reaches a maximum at a specific MNP concentration. We refer this to agglutination of the particles by macromolecular bridges between the nanoparticle shells. Analysis of the scaling behaviour helps to identify the bridging component of the suspension medium that causes agglutination. |
