Detection of 130nm magnetic particles by a portable electronic platform using spin valve and magnetic tunnel junction sensors

Abstract

An integrated biosensor with magnetic tunnel juntions (MTJs) and spin valve (SV) sensor was used for 130nm particle detection. A platform drives an external magnet generating an in-plane dc+ac magnetic field on the sensor at frequencies up to 375Hz, provides a current to bias the sensor, and performs the signal acquisition and treatment. The signal-to-noise ratio of the SV and MTJ was characterized. Bead detection (130nm in diameter) was performed using both sensors leading to a detection limit of 3×108particles∕ml for SV and 3×1010particles∕ml for MTJ.