One-step microfluidic synthesis of Janus particles with controllable magnetic nanoparticle proportion and their magnetoresponsive motion

Magnetic Janus particles have been widely used in medicine, chemistry, and biology fields due to their controllability in fluid media. This study used a microfluidic device to achieve one-step synthesis of Janus particles with controlled magnetic proportion. The content of magnetic nanoparticles in Janus particles can be flexibly adjusted by precisely controlling the flow rate in a theta-shaped capillary. The Janus particles exhibit a monodisperse size distribution with a coefficient of variation of less than 2 % after UV curing. By applying an external magnetic field, these Janus particles exhibit excellent magnetoresponsive motion and anisotropy in their dynamic response. In addition, serialized droplets are manipulated using this magnetic Janus particle, achieving stepwise reactions, which enable to be applied to targeted drug delivery or micro reaction processes.