Title :
Detection of 10-nm Superparamagnetic Iron Oxide Nanoparticles Using Exchange-Biased GMR Sensors in Wheatstone Bridge
Author :
Li, Luoqing ; Mak, K.Y. ; Leung, C.W. ; Ng, S.M. ; Lei, Z.Q. ; Pong, Philip W. T.
Author_Institution :
Dept. of Electr. & Electron. Eng., Univ. of Hong Kong, Hong Kong, China
Abstract :
We demonstrated the use of exchange-biased giant magnetoresistance (GMR) sensors in Wheatstone bridge for the detection of 10-nm superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs were synthesized via coprecipitation method, exhibiting a superparamagnetic behavior with saturation magnetization of 57 emu/g. The output voltage signal of the Wheatstone bridge exhibits log-linear function of the concentration of SPIONs (from 10 ng/ml to 0.1 mg/ml), making the sensors suitable for use as a SPION concentration detector. Thus the combination of 10 nm SPIONs and the exchange-biased GMR sensors has potential to be used in the bio-detection applications where ultra-small bio-labels are needed.
Keywords :
chemical sensors; giant magnetoresistance; iron compounds; magnetic particles; magnetic sensors; magnetisation; magnetoresistive devices; nanofabrication; nanomagnetics; nanoparticles; nanosensors; precipitation (physical chemistry); superparamagnetism; Fe2O3; SPION; SPION concentration detector; Wheatstone bridge; biodetection application; coprecipitation method; exchange-biased GMR sensors; exchange-biased giant magnetoresistance sensors; log-linear function; output voltage signal; saturation magnetization; size 10 nm; superparamagnetic iron oxide nanoparticles; ultrasmall biolabels; Biosensors; Bridge circuits; Magnetic sensors; Magnetometers; Nanoparticles; Saturation magnetization; Giant magnetoresistance (GMR); magnetic sensor; superparamagnetic nanoparticles;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2013.2237889
