The present invention relates to a microfluidic device to manipulate, select, treat, or cultivate living bodies, comprising a first chamber, a second chamber and a network of guiding tracks, wherein: said network of guiding tracks comprises at least one first guiding track connecting the first chamber and the second chamber and at least one second guiding track connecting said at least one first guiding track with at least two interconnections; and said at least one second guiding track comprises a curved part; said curved part exhibiting a concavity facing the second chamber or the part of the network connected to the second chamber.