Magnetoresistive Biosensors for Direct Detection of Magnetic Nanoparticle Conjugated Biomarkers on a Chip

In this review, we introduce various magnetic biosensors that have been developed. We first explain the advantages of magnetic biosensing and their general operating principles as well as the biolabeling technique for magnetic nanoparticles. Next, we focus on magnetoresistive biosensing technologies because magnetoresistive biosensors will be an essential development direction due to the demand for miniaturization and portable lab-on-a-chip devices. The magnetoresistive effects employed in biosensing include anisotropic magnetoresistance, giant magnetoresistance and tunneling magnetoresistance. In addition to magnetoresistive sensors, the advantages and disadvantages of some nonmagnetoresistive magnetic biosensors are discussed and compared. Finally, we introduce research on integrating magnetic biosensors into the microfluidic laboratory-on-a-chip systems and comment on future development trends.