Continuous magnetic droplets and microfluidics: generation, manipulation, synthesis and detection.

In this review, an introduction is given to provide the fundamental principles of magnetic droplet microfluidics. This is followed by a thorough discussion of methods that have been developed for the continuous generation of magnetic droplets and their controlled and precise manipulation by using external magnetic fields. Next, attention is given to techniques devised for the continuous fabrication of magnetic materials in droplets with an emphasis on the synthesis and modification of magnetic nanoparticles (MNPs), magnetic microstructures, Janus microparticles and magnetic hydrogels. In addition, selected applications of continuous magnetic droplets in (bio)assays and detection methods are discussed. The review (with 113 refs.) ends with concluding remarks and a discussion of current challenges and the future outlook for the field of continuous magnetic droplet microfluidics. Graphical abstract Continuous generation of magnetic droplets in microfluidic devices has the advantage of producing droplets at high frequencies and therefore has been exploited for the synthesis and generation of magnetic microparticles, manipulation, performing (bio)assyas and detection of magnetic contents.