Evolution of Structural and Magnetic Properties of Magnetite Nanoparticles for Biomedical Applications
Artikel i övriga tidskrifter, 2010

We have investigated the evolution of microstructure and magnetic properties of thermally blocked magnetite nanoparticles, aimed for immunoassay applications, during their synthesis. High-resolution transmission electron microscopy (HRTEM) investigations of the size, size distribution, morphology, and crystal structure of particles reveal that particles at an early stage of the reaction process are either single crystals or polycrystals containing planar faults and they grow via a combination of reactant (monomer) consumption and oriented attachment at specific crystallographic surfaces because of the strong dipolar character of the < 111 > surfaces of magnetite. At a later stage of the synthesis reaction, the magnetic attraction strives to align contacting particles with their < 111 > axis of easy magnetization in parallel and this may also be an active driving force for crystal growth. At latter stages, the crystal growth is dominated by Ostwald ripening leading to smoother crystalline particles with a mean diameter of 16.7 +/- 3.5 nm and a narrow size distribution. The magnetic properties of the particles measured using static and dynamic magnetic fields are consistent with the evolution of particle size and structure and show the transition from superparamagnetic to thermally blocked behavior needed for magnetic relaxation-based immunoassay applications.

ACCRETION

DEFECT GENERATION

GROWTH-KINETICS

NANOCRYSTALLINE

MAGNETOTACTIC BACTERIA

ORGANIZATION

ZNS

CRYSTAL-GROWTH

IMPERFECT ORIENTED ATTACHMENT

DYNAMICS

PARTICLES

Författare

Stefan Gustafsson

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

SuMo Biomaterials

A. Fornara

The Royal Institute of Technology (KTH)

K. Petersson

Imego AB - The Institute of Micro and Nanotechnology

C. Johansson

Imego AB - The Institute of Micro and Nanotechnology

M. Muhammed

The Royal Institute of Technology (KTH)

Eva Olsson

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Crystal Growth & Design

1528-7483 (ISSN) 1528-7505 (eISSN)

Vol. 10 2278-2284

Ämneskategorier

Annan teknik

DOI

10.1021/cg901602w