Fabrication of Monodisperse Magnetic Janus Nonspherical Microparticles with Controllable Structural Features

This work reports on a microfluidic strategy based on adhesion-energy-induced evolution of double emulsions for controllable fabrication of Janus non-spherical microparticles. With solvent evaporation to reduce the solvent quality of the middle oil phase for surfactants, the W/O/W double emulsions with the middle oil phase undergo an adhesion-energy-induced dewetting process for structural evolution. Such an evolution enables the double emulsions evolving from a core-shell configuration to a dumbbell-like non-spherical configuration, which provides good templates for creating the Janus non-spherical microparticles. The resultant microparticles show unique Janus non-spherical structures with an aqueous hollow cavity half and a hydrophobic polyETPTA half. This one-step fabrication approach enables the controllable synthesis of asymmetric structures, effectively circumventing the limitations associated with multistep modification processes traditionally employed. Meanwhile, the encapsulation of hydrophilic/hydrophobic drugs within the inner phase facilitates efficient loading during microparticle formation. Furthermore, the density disparity of the non-spherical structure inherently induces an imbalance in hydrodynamic forces, thereby enhancing the kinetic properties of the microparticles and improving their capability for cargo transport. The integration of magnetic nanoparticles into the double emulsions not only imparts magnetic functionality to the microparticles but also enhances their directional mobility under magnetic guidance, enabling targeted transport along predefined pathways. Based on these features, the Janus non-spherical microparticles exhibit excellent performance for the encapsulation of actives and magnetic-guided motion and show faster motion with the water flow in a microchannel than their spherical counterparts. This structural design offers a novel strategy for the construction of multifunctional microcarriers, holding particular promise for applications in tumor synergistic therapy, cascade catalytic reactions, and intelligent microrobotics.