A microfluidic system comprises a first portion and a second portion. The first portion comprises a material which is able to change its volume when activated by an exciting factor, characterized by the fact that the first portion and the second portion define a zone which, when the first portion is not yet activated by the exciting factor, shows a first topography devoid of any fluidic pathway and which, after activation by the exciting factor, shows a second topography which is adapted to contain at least one fluidic pathway. The microfluidic system further comprises a tight cover surface situated above the first portion and the second portion.