The applications of microsystems has steadily widened over the last fifteen years in particular to communication or biotechnology. To increase the functionality of microsystems, the use of nano-objects seems to be an inevitable path, but often exposed to integrate them into a functional architecture. To solve these problems of integration, the use of directed assembly phenomena, ie the physical phenomena to manipulate nano-objects collectively seems very promising. In this context, the objective of our thesis was to develop tools capable of realizing innovative fluid handling operations or conformational space of nano-objects or molecules. This is a multidisciplinary research at the frontier between micro and nano-fabrication, micro-and nano-fluidics, molecular biology, imaging of individual molecules, and biophysics. The thesis consists of two relatively independent projects: a study of nanofluidics for the conformational control of chromosomes from living cells, and work on a microfluidic phenomenon of spontaneous assembly on hydrophilic gel. At first, we describe a method for producing structured hydrogels, and we show that these hydrogels are an effective medium for spatially organize nano-objects. This organization is spontaneous, and it occurs during the drying liquid. We wanted to understand the mechanisms of fluid during drying using fluorescent tracers.We identify several phenomena explaining the phenomena of spatial organization of particles, and propose applications for this innovative process. Thanks to nanofluidic devices that we have made, we conduct experiments manipulating individual DNA molecules in a confined environment. We analyze the behavior of DNA - its extension, its mobility, the effect of salinity, the role of the material in which the nanochannels are fabricated - using two operating modes, namely electrophoresis and hydrodynamic , and we show, for the first time, the interest of hydrodynamics for DNA manipulation in nano structures. Finally, we propose some applications for this method of manipulating DNA innovative.
