In situ detection of single micron-sized magnetic beads using magnetic tunnel junction sensors

We have demonstrated the use of highly sensitive magnetic tunnel junction (MTJ) sensors for the detection of individual micron-sized magnetic labels. By integrating the MTJ sensor into a microfluidic channel, we were able to detect the presence of moving superparamagnetic beads (Dynabeads® M-280) in...

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Bibliographic Details
Published in:Applied physics letters 2005-06, Vol.86 (25), p.253901-253901-3
Main Authors: Shen, Weifeng, Liu, Xiaoyong, Mazumdar, Dipanjan, Xiao, Gang
Format: Article
Language:English
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Summary:We have demonstrated the use of highly sensitive magnetic tunnel junction (MTJ) sensors for the detection of individual micron-sized magnetic labels. By integrating the MTJ sensor into a microfluidic channel, we were able to detect the presence of moving superparamagnetic beads (Dynabeads® M-280) in real time by direct measurement of the magnetic dipole fields associated with single beads. The dipolar fields of a single bead were sufficient to obtain a signal of 80 μ V with signal to noise ratio of 24 dB in an applied field of 15 Oe . Our data show conclusively that MTJ sensors are very promising candidates for future applications involving the accurate detection and identification of biomolecules with magnetic labels.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.1952582