Development of a DNA Biosensor Using Magnetic Nanoparticles and Giant Magnetoresistance Sensor on Graphene Sheets

Abstract

Graphene sheets were functionalized with fluorine or oxygen using plasma treatment under C3F8 gas or O-2 gas environment to fabricate DNA micropatterns. The regions on the outer side of the micropatterns were passivated with fluorine, and changes on the two different surfaces, oxygen groups on the inside of the patterned regions and fluorine on the outside of the patterned regions. The plasma treated areas were characterized by spatially resolved X-ray photoelectron spectroscopy (XPS). Probe DNA was selectively immobilized on the oxygenated graphene sheet via bifunctional molecules. Magnetic nanoparticles (MNPs) were used as a label to detect hybridization of specifically sequenced DNA. And we detected the specific sequenced DNA hybridization using giant magnetoresistance (GMR) sensors. The concentration of target DNA was 100 nM in 2x SSC containing 0.2% SDS. The shift voltage of the GMR sensor when the 5' MNP-labeled complementary and noncomplementary target DNA hybridized with the probe DNA was 86.12 +/- 16.37 mV and -24.74 +/- 5.60 mV, respectively.