Giant magneto resistance (GMR)-based microfluidic biosensors are used in applications involving the detection, analysis, enumeration and characterization of magnetic nano-particles attached to biological mediums such as antibodies and DNA. Here we introduce a novel multilayered CoNiCu/Cu nanowire GMR-based microfluidic biosensor. The current perpendicular to the plane of multilayers (CPP)-nanowires GMR was used as the core sensing material in the biosensor which responds to magnetic fields depending on the concentration and the flow velocity of bio-nano-magnetic fluids. The device was tested with different control solutions such as DI-water, mineral oil, phosphate buffered saline (PBS), ferrofluid, polystyrene superparamagnetic beads (PSB) and Dynabeads sheep anti-rabbit IgG. The nanowire array resistance decreased with an increase in the ferrofluid concentration, and a maximum 15.8% relative GMR was observed for the undiluted ferrofluid. The sensor was also responding differently to various ferrofluid flow rates. The GMR device showed variation in the output signal when the PSB and Dynabeads of different dilutions were pumped through it. When the tests were performed with pulsing potentials (150 mV and 200 mV), an increased GMR response was identified at higher voltages for PSB and Dynabeads sheep anti-rabbit IgG.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering