Microfluidic-based synthesis of non-spherical magnetic hydrogel microparticles.

Spherical and non-spherical magnetic hydrogel particles were synthesized in a microfluidic device containing an embedded UV light reflector. Monodisperse magnetic emulsion droplets were generated in a T-junction and allowed to relax into spheres, disks, and plugs in confining microchannel geometries. Particle morphology was locked-in via UV-initiated photopolymerization. The role of the reflector in the microchannel is to provide a uniform distribution of UV energy to the magnetic emulsion droplets and to increase the UV flux, which significantly improves UV polymerization conditions for microfluidic-based particle synthesis. Magnetic nanoparticles were uniformly encapsulated in the hydrogel, giving the microparticles superparamagnetic behavior. Additionally, the non-spherical particles show anisotropic responses under an applied external magnetic field.