Process of fabrication of a microfluidic chip. (a)-Ink is deposited on the substrate in liquid phase where it freezes immediately. (b)-Additionnal elements can be added. Here some elements for the connections and a casing to avoid the spreading of PDMS. (c)-The system is immersed in PDMS which is cross-linked at a temperature below the melting point of the ink. (d)-The ink is evaporated, leaving open channels. The system can be used directly or removed from the substrate for further application.