Engineering Micromotors with Droplet Microfluidics

Micromotors have promising potential in applications ranging from environmental remediation to targeted drug delivery and noninvasive microsurgery. However, there are inadequacies in the fabrication of artificial micromotors to improve the design of structure and composition for motion performance and multifunctionality. Here, we present a microfluidic fiber-confined approach to creating droplet-templated micromotors with precisely engineered anisotropies in 3D structures and material compositions. The shape anisotropy comes from controllable deformation in droplet templates, and material anisotropy originates from versatile emulsion templates. Containing Pt and magnetic nanoparticles (NPs), micromotors are endowed with both catalytic propulsion and magnetic guidance, which are capable of performing tasks of precise catching, skillful delivering, and on-demand releasing of cargos. Droplet microfluidics allows us to systematically and independently vary the shape and size of micromotors and the distribution and content of NPs for the study of their influences on motors' mobility and improve the design. Our results are useful for fabricating micromotors with well-controlled morphology and composition that is beneficial to designing sophisticated microrobotic systems for real-world applications.