A device for extracting a liquid phase depleted of particles of a biological suspension, including: - a main duct for flowing said suspension, the main duct including a fractionating cell including at least one singularity location adapted to cause the formation of at least one recirculation vortex, and - at least one liquid sampling means, disposed at a region of the fractionating cell where said suspension is depleted of particles because of said recirculation vortex, the main duct includes a clear layer pre-configuring channel disposed upstream of the fractionating cell, said pre-configuring channel having a length higher than a predetermined stability boundary length to form a clear layer in the vicinity of its walls, said fractionating cell and said pre-configuring channel being formed on a same substrate, and in that said device further includes: - at least one first tank (23a, 23b) provided to recover said liquid phase depleted of particles, - at least one second tank provided to recover the remaining phase enriched with particles from said suspension, said at least one first tank and said at least one second tank are integrated in said device; - a control means provided to suck in the suspension during a first actuation in order to bring it into the fractionating cell where it is fractionated into a first liquid fraction depleted of particles and a second fraction enriched with particles and to guide said first fraction to said at least one first tank (23a, 23b) and said second fraction to said at least one second tank, said control means being configured during a second actuation to eject said liquid phase depleted of particles or said liquid phase enriched with particles. - a main duct for flowing said suspension, the main duct including a fractionating cell including at least one singularity location adapted to cause the formation of at least one recirculation vortex, and - at least one liquid sampling means, disposed at a region of the fractionating cell where said suspension is depleted of particles because of said recirculation vortex, the main duct includes a clear layer pre-configuring channel disposed upstream of the fractionating cell, said pre-configuring channel having a length higher than a predetermined stability boundary length to form a clear layer in the vicinity of its walls, said fractionating cell and said pre-configuring channel being formed on a same substrate, and in that said device further includes: - at least one first tank (23a, 23b) provided to recover said liquid phase depleted of particles, - at least one second tank provided to recover the remaining phase enriched with particles from said suspension, said at least one first tank and said at least one second tank are integrated in said device; - a control means provided to suck in the suspension during a first actuation in order to bring it into the fractionating cell where it is fractionated into a first liquid fraction depleted of particles and a second fraction enriched with particles and to guide said first fraction to said at least one first tank (23a, 23b) and said second fraction to said at least one second tank, said control means being configured during a second actuation to eject said liquid phase depleted of particles or said liquid phase enriched with particles.