Rapid and flexible actuation of droplets via a low-adhesive and deformable magnetically functionalized membrane

Swift and convenient handling of discrete micro-droplets on digital microfluidics platform has recently attracted plentiful interest in high-throughput bio/chemical analysis. In this work, we developed a novel and facile approach to manipulate the micro-droplet based on a hydrophobic and low-adhesive magnetically functionalized polydimethylsiloxane (MF-PDMS) membrane. The platform is composed of the MF-PDMS membrane as the substrate, integrated with non-magnetic PDMS micro-pillar arrays on-top to ensure the low adhesion between the platform and the resident drops. With applied magnetic field, the localized membrane deformation could induce the unbalanced force imposed on the micro-droplet, leading to free rolling-off for flexible control including the position and velocity, etc. We have experimentally verified that the proposed avenue could be successfully applied for kinds of on-chip micro-droplet manipulations, such as droplet merging, parallel manipulation, flexible trajectory control. With the flexibility and maximum velocity reported herein (~ 79 ± 6 mm/s), we believe that the presented platform could be potentially applied for biological or chemical analysis where precise manipulation of large amounts of individual droplets is critical.