Magnetic particle actuation in stationary microfluidics for integrated lab-on-chip biosensors

The aging population and increases in chronic diseases put high pressure on the healthcare system, which drives a need for easy-to-use and cost-effective medical technologies. In-vitro diagnostics (IVD) plays a large role in delivering healthcare and, within the IVD market, decentralized diagnostic testing, i.e. point-of-care testing (POCT), is a growing segment. POCT devices should be compact and fully integrated for maximum ease of use. A new class of POCT technologies is appearing based on actuated magnetic particles. The use of magnetic particles has important advantages: they have a large surface-to-volume ratio, are conveniently biofunctionalized, provide a large optical contrast, and can be manipulated by magnetic fields. In this chapter, we review the use of magnetic particles actuated by magnetic fields to realize integrated lab-on-chip diagnostic devices wherein several assay process steps are combined, e.g. to mix fluids, capture analytes, concentrate analytes, transfer analytes, label analytes, and perform stringency steps. We focus on realizations within the concept of stationary microfluidics and we discuss efforts to integrate different magnetically actuated assay steps, with the vision that it will become possible to realize biosensing systems in which all assay process steps are controlled and optimized by magnetic forces.