Bio-functionalization of monodisperse magnetic nanoparticles and their use as biomolecular labels in a magnetic tunnel junction based sensor.
Monodisperse magnetic nanoparticles (NPs) could enable the ultra-sensitive magnetic detection of biological analytes. However, rendering these particles biocompatible has remained a challenge. We report the bio-functionalization and detection of 12-nm manganese ferrite NPs. We have achieved the site-specific binding of biotin-functionalized NPs onto avidin-patterned silicon oxide substrates and DNA-functionalized NPs onto complementary DNA-patterned silicon oxide substrates. Utilizing scanning SQUID microscopy, we show that these substrate-bound NPs retain their magnetic properties. Finally, we demonstrate a novel method of detecting either protein binding or DNA hybridization at room temperature using the NPs and a magnetic tunnel-junction-based biosensor situated in orthogonal magnetic fields.
Grancharov
Stephanie G
SG
IBM T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598, USA.
Zeng
Hao
H
Sun
Shouheng
S
Wang
Shan X
SX
O'Brien
Stephen
S
Murray
C B
CB
Kirtley
J R
JR
Held
G A
GA
D001360:Avidin / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry*; D008280:Magnetics; D008345:Manganese / Q000737:chemistry*; D053758:Nanoparticles; D009693:Nucleic Acid Hybridization; D012822:Silicon Dioxide / Q000737:chemistry
D004277:DNA, Single-Stranded; D005290:Ferric Compounds; D001360:Avidin; D008345:Manganese; D001710:Biotin; D012822:Silicon Dioxide