Abstract: The invention relates to a method of forming a microfluidic array comprising at least one channel of semi-circular section, comprising the following steps: bringing into contact a first liquid (7) with an array of electrodes (3) of a microfluidic chip (1) comprising at least one pair of substantially parallel and coplanar electrodes (3a, 3b) arranged on a substrate (4), activating said array of electrodes so as to actuate by liquid dielectrophoresis LDEP said first liquid to form a fluidic structure (9) comprising at least one fluidic finger (9a), and using said fluidic structure as a mould to form said microfluidic array by solidification or hardening of a second liquid (11) deposited on the microfluidic chip and hugging the shape of said fluidic structure.