Concentration Detection of Continuous-Flow Magnetic Nanoparticles Using Giant Magnetoresistance Sensor

Giant magnetoresistance (GMR) sensors offer great sensitivity and integration capabilities on devices, especially microfluidic systems. This approach allows fast identification and real-time analysis of the detection of the biomolecules conjugated with the magnetic nanoparticles (MNPs), which are essential requirements for biomedical applications. This study integrated the GMR sensor with microchannel and signal processing circuits to determine MNPs concentration in a continuous flow using Helmholtz magnetic field source. The most significant advantage of this technique consists of modifying and integrating the GMR sensor to enhance the output signal and the system’s sensitivity at a shallow concentration of MNPs. The high sensitivity was experimentally determined as 3.018V/(mg.mL
^-1
) with a low detection limit (LOD) of about 19 μg.mL
^-1
. This proposed system is appropriate to integrate into point-of-care microfluidic devices to detect biomolecule concentrations in real-time diagnostics.