A 128-Pixel Digitally-Programmable Microfluidic Platform for Non-Contact Droplet Actuation using Marangoni Flows

A contactless programmable fluidic processor utilizing Marangoni flows is presented. Two dimensional control of microdroplets suspended in oil is achieved using a 128-pixel heater array suspended 100-500 μm above the oil layer. The heaters create surface temperature perturbations (<7°C simulated), resulting in local recirculating Marangoni flows which can move droplets in either a push or pull mode. Programmed movement is achieved by the sequential activation of the heaters. Addressible control of each heater is provided by digital circuitry and a graphical interface. Droplets with diameters 300-1000 μm can be manipulated and merged at speeds up to 140 μm/s. This system provides a platform for high-throughput droplet-based assays where the reagents do not contact any solid surface.