Magnetic Actuation Multifunctional Platform Combining Microdroplets Delivery and Stirring.

Multifunctional droplets manipulation devices are in urgent need for various laboratory operations such as chemical reaction and biological analysis. However, most current techniques that achieved a controllable droplet transport system mainly rely on passive diffusion for mixing, limiting their practical applications. Here, we develop a magnetic controlled dimple on slippery surface (MCDSS) that enables arbitrary direction or even uphill droplet transport through the synergy between gravitational force and asymmetrical droplet deformation. Further experiments demonstrate that our system could also be used for stirring microdroplets and accelerating the mixing speed by more than one hundred times. In addition, the microstir strategy could help to avoid locally uneven production of precipitation or gas in heterogeneous reactions. This combination of droplet delivery and agitation may have a promising future for application in various fields, for example, laboratory-on-a-chip platforms and microengines.