A method for removing fluid in a microfluidic device, the microfluidic device having a fluid channel, a first well, and a second well, the first well and the second well being coupled to a first end of the fluid channel, the method including applying a pressure difference between the second well and the first well, and applying a pressure difference between the first end and a second end of the fluid channel being below a certain threshold, for at least partly removing a first fluid from a first supply line coupled between the first well and the first end of the fluid channel.