Fabrication of a T-Shaped Microfluidic Channel Using a Consumer Laser Cutter and Application to Monodisperse Microdroplet Formation

The use of micrometer-sized droplets for chemical and biochemical analysis has been widely explored. Photolithography is mainly used to fabricate microfluidic devices, which is often employed to form monodisperse microdroplets. Although photolithography enables precise microfabrication, it is not readily available to biochemists because it requires specialized equipment such as clean room and mask aligners, and expensive consumables such as photoresist and silicon wafers. In this study, we fabricated a microfluidic device using a consumer laser cutter and applied it to droplet formation. Monodisperse microdroplets were formed by using an oil phase for droplet digital polymerase chain reaction (PCR) as the continuous phase and phosphate-buffered saline or polyethylene glycol solution as the dispersed phase. The droplet size decreased as the flow rate of the continuous phase increased and approached a constant value. The method developed in this study can be used to realize microdroplet-based biochemical analysis with simple devices or to construct artificial cells.