New magnetic nanoparticles for biotechnology.
Paramagnetic carriers, which are linked to antibodies enable highly specific biological cell separations. With the colloidal synthesis of superparamagnetic Co and FeCo nanocrystals with superior magnetic moments the question about their potential to replace magnetite as the magnetically responsive component of magnetic beads is addressed. Starting from a magnetic analysis of the corresponding magnetophoretic mobility of Co and FeCo based alloys their synthesis and resulting microstructural and magnetic properties as function of the underlying particle size distribution are discussed in detail. The stability of the oleic acid ligand of Co nanocrystals has been investigated. The oxidation kinetics were quantified using magnetic measurements. As a result, this ligand system provides sufficient protection against oxidation. Furthermore, the kinetics of the synthesis of Fe(50)Co(50) nanoparticles has been monitored employing Fourier transform infra red (FT-IR) spectroscopy and is modeled using a consecutive decomposition and growth model. This model predicts the experimentally realized FeCo nanoparticle composition as a function of the particle size fairly well. High-resolution transmission electron microscopy (HRTEM) was performed to uncover the resulting microstructure and composition on a nanometer scale.
Thin Films and Nanostructures, Faculty of Physics, University of Bielefeld, Universitäts Str. 25, D-33615 Bielefeld, Germany. huetten@physik.uni-bielefeld.de
Andreas
A
Hütten
Daniela
D
Sudfeld
Inga
I
Ennen
Günter
G
Reiss
Wiebke
W
Hachmann
Ulrich
U
Heinzmann
Klaus
K
Wojczykowski
Peter
P
Jutzi
Wahib
W
Saikaly
Gareth
G
Thomas
D000497:Alloys; D001704:Biopolymers / Q000032:analysis* / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D001709:Biotechnology / Q000295:instrumentation / Q000379:methods; D003035:Cobalt / Q000737:chemistry* / Q000528:radiation effects; D003460:Crystallization / Q000379:methods; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields; D018189:Immunomagnetic Separation / Q000295:instrumentation / Q000379:methods; D007501:Iron / Q000737:chemistry* / Q000528:radiation effects; D008280:Magnetics; D008846:Micromanipulation / Q000295:instrumentation / Q000379:methods*; D008863:Microspheres; D008968:Molecular Conformation; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties; D014159:Transducers
D000497:Alloys; D001704:Biopolymers; D003035:Cobalt; D007501:Iron