Scanning magnetoresistance microscopy for imaging magnetically labeled DNA microarrays

Mei Lin Chan, Gerardo Jaramillo, Ahjeong Son, Krassimira R. Hristova, David A. Horsley

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We demonstrate the use of a magnetic tunnel junction (MTJ) sensor as a probe for non-contact scanning microscopy of magnetically labeled DNA microarrays. Induced magnetic stray fields from 2.8 μm diameter magnetic particles are detected using the MTJ sensor, while two dimensional scanning generates the magnetic map of the DNA microarray with a spatial resolution of 1 μm over a large scan area exceeding 1 cm2. Current particle-sensor spacing of ∼20 μm results in a detection resolution of ∼30 magnetic particles within each 100 μm diameter DNA spot. Our results highlight the use of scanning magnetoresistive microscopy as a convenient and powerful technique for the accurate detection and identification of biomolecules tagged with magnetic particles.

Original languageEnglish
Article number5257293
Pages (from-to)4816-4820
Number of pages5
JournalIEEE Transactions on Magnetics
Issue number10
StatePublished - Oct 2009

Bibliographical note

Funding Information:
This work was supported in part by the National Science Foundation under Grant No. ECCS 0601383. The authors would like to thank J. Pfeiff from the Arraycore Facility at UC Davis for the DNA microarray printing as well as Micromagnetics Inc. for valuable discussions.


  • Biosensor
  • DNA microarray
  • Magnetic imaging
  • Magnetic tunnel junction (MTJ


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