Challenges and trends in magnetic sensor integration with microfluidics for biomedical applications

Magnetoresistive (MR) sensors have been successfully applied in many technologies, in particular readout electronics and smart systems for multiple signal addressing and readout. When single sensors are used, the requirements relate to spatial resolution and localized field sources. The integration of MR sensors in adaptable media (e.g. flexible, stretchable substrates) offers the possibility to merge the magnetic detection with mechanical functionalities. In addition, the precision of a micrometric needle can benefit greatly from the integration of MR sensors with submicrometric resolution. In this paper, we demonstrate through several detailed examples how advanced MR sensors can be integrated with the systems described above, and also with microfluidic technologies. Here, the challenges of handling liquids over a chip combine with those for miniaturization of microelectronics for MR readout. However, when these are overcome, the result is an integrated system with added functionalities, capable of answering the demand in biomedicine and biochemistry for lab-on-a-chip devices.