Microfluidic device, system and method for encapsulating particles or particle clusters under control

摘要

The microfluidic device (D) for controlled encapsulation of particles of sub-millimetric size or clusters of such particles e.g. bacteria cells, comprises a first microfluidic duct for feeding a first liquid phase containing suspended particles or clusters of particles, a second microfluidic duct for circulating a second liquid phase immiscible with the first liquid phase, and a microfluidic duct of evacuation of the first liquid phase circulating in the first duct. The first duct opening in the second duct forms a fluidic junction with the duct. The microfluidic device (D) for controlled encapsulation of particles of sub-millimetric size or clusters of such particles e.g. bacteria cells, comprises a first microfluidic duct for feeding a first liquid phase containing suspended particles or clusters of particles, a second microfluidic duct for circulating a second liquid phase immiscible with the first liquid phase, and a microfluidic duct of evacuation of the first liquid phase circulating in the first duct. The first duct opening in the second duct forms a fluidic junction with the duct. The microfluidic duct is provided by a nozzle, which is laid in upstream of the junction and able to be partially clogged by a particle or clusters of particles in suspension thus causing an overpressure in the first duct. Particles or particle clusters moved by the suspension along the first duct accumulate at the level of the junction, and are trapped at an interface between the two immiscible liquid phases to be injected into the second duct by the overpressure caused by obstruction of mouth of the evacuation duct. The distance from the junction and the section of the first duct are chosen so that the arrival of a single particle or cluster of particles at the junction induces a pressure in the first duct sufficient for injecting the particle or cluster of particles in the second duct. The section of the mouth of the evacuation ducts and its distance from the junction and the section of the first duct are chosen so that sufficient pressure injecting a particle or cluster particles in the second duct is reached when the two ducts or pair of ducts are blocked through which the simultaneous injection of particles or particle clusters is obtained. The fluidic junction is T junction, and a microfluidic flow focusing junction. The first and second duct are separated by an angle of 90[deg] . The first and second ducts are of sections having a diameter of 110-130%. A micro-pillar network is present at each mouth of the evacuation ducts, and at the fluidic junction between the first and the second duct. The ducts are constituted by etched or molded groove in a substrate. The device has a three dimensional structure, and is constituted by a stack of molded or etched planar substrates in which the first duct passes perpendicularly to the substrates, while the second duct and the evacuation ducts are formed at the interfaces between substrates and parallel to the substrates.