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Universidad de Oviedo
Phisiologicaly stable magnetic nanoparticles
and magnetoimpedance sensor
D. Lago*, M. Rivas, J.C. Martínez-García, J.A. García
Dpto. de Física, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo, Spain
* Edificio Departamental Este, Campus de Viesques, 33204 Gijón, Spain e-mail: [email protected]
References
1. J.C. Martínez-García, M. Rivas, L. Elbaile, R. Díaz-Crespo, J.A. García and S. Volchkov; Sens. Lett. 7 (2009) p. 497.
2. A. Kumar, S. Mohapatra, V. Fal-Miyar, A. Cerdeira, J.A. García, H. Srikanthy, J. Gass and G.V. Kurlyandskaya; Appl. Phys. Lett. 91 (2007) p. 143902.
3. N Gao, H. Wang, and E-H. Yang; Nanotechnology 21 (2010) p. 105107.
The aim of this Project is in vitro labeling, magnetic detection and separation of tumor cells. Magnetite nanoparticles or functionalized nickel na-
nowires are bound to the specific antibody against the surface protein of the tumor. The nanoestructures are then detected by a magnetic biosensor
based on the Giant MagnetoImpedance (GMI) effect of an Co-based amorphous metallic ribbon[1]
. Similar nanoparticles have been detected embed-
ded inside human embryonic kidney cells[2]
, and the use of antibody-functionalized nanowires for cell separation has also been studied[3]
, showing low
citotoxicity without any biocompatible coating.
In a first step we produced 10 nm diameter iron oxide nanoparticles, with narrow size distribu-
tion. Secondly, the nanoparticles were covered with a biocompatible silica surface coating, con-
serving the spherical form, the superparamagnetic behaviour and the narrow size distribution, as
shown in the transmision electron micrography of nanoparticles. The thicker the silica coating, the
weaker the magnetic field which can be detected. Hysteresis loops of the naked magnetite nano-
particles, nanoparticles covered with 5 nm silica (20 nm total diameter of nanoparticle), and nano-
particles with 10 nm silica (40 nm total diameter) were measured using a SQUID. Finally, the nano-
particles were conjugated to the specific targeting ligands.
Fe3O4@SiO2 d~40nm
Fe3O4@SiO2 d~20nm
Fe3O4 d~10nm
We have produced Co70Fe5Si15B10 by melt-spinning which in as-quenched state presents large GMI that allows the detection of nanowires.
This project is done in collaboration with Nanogap and financed under grant IB09-128 by the Government of the Principality of Asturias
Fe3O4
nanoparticle
Fe3O4@SiO2
nanoparticle
Functionalized
nanoparticle with
Specific Antibody
Functionalized
Nanowire with
Ni Nanowire
Nanoparticles’
Magnetic Field
Nanowires’
Magnetic Field
Detection System
Ribbon
with
GMI
Tumor Cell
Tumor Cell
After annealing and
premagnetization
GMI curves of as-quenched ribbon showing the
effect of nanowires.
GMI curves of premagnetized ribbon impedan-
ce showing the effect of nanowires.
Nanowires detection with annealed and premag-
netized ribbon with no applied field.
Measuring with
H = 0
Detection
No detection
Detection
