There is provided a microfluidic device comprising: a plurality of wells, each well having an inlet and an outlet, wherein the inlets are in fluid communication with one or more entry channels and the outlets are in fluid communication with one or more exit channels, wherein said outlet is connected to the exit channel via an outlet connecting channel and said inlet is connected to the entry channel via an inlet connecting channel wherein the dimension of the outlet connecting channel is configured such that the surface tension of a liquid comprised in the well prevents the release of the liquid through the outlet connecting channel. There is also provided a system, method and use of the device.