The invention relates to a micro fluidic system comprising a substrate, and, provided on said substrate, at least one flow path interconnecting with functional means in which liquid samples can be treated by desired procedures. The flow paths are laid out to form a pattern for the transport of liquid samples to and from said functional means. These flow paths comprise a plurality of micro posts protruding upwards from said substrate, the spacing between the micro posts being small enough to induce a capillary action in a liquid sample applied anywhere within any of said flow paths, so as to force said liquid to move from where said liquid sample was applied.