Synthesis and active sorting of magnetic liquid beads

Abstract

This paper reports the fabrication and characterization of magnetic liquid beads using microfluidic techniques. The liquid beads consist of a fluorinated oil core and a polymer shell embedded with magnetite particles. The beads are generated in a flow-focusing PDMS device and cured by photopolymerisation. The mobility response of the beads to an external magnetic field was investigated by characterising their motion towards a permanent magnet. Magnetic sorting of liquid beads with 90% efficiency was achieved due to the unique magnetic property of the shell. The results show that the liquid beads can be controlled magnetically and have potential applications in drug delivery, bioimaging, sensing, and tissue engineering. The present paper also discusses the effects of parameters such as magnetite concentration, bead size, and mass on the magnetic force and sorting efficiency.