Sizing of a microfluidic device for confining a sample

A method of manufacturing a microfluidic device, the microfluidic device including:

• an input zone adapted to receive a carrier fluid medium and a sample in suspension in the carrier fluid medium, the sample comprising at least one population of cells or microparticles, the input zone corresponding to a cylindrical input tank of diameter Din,
• a confinement zone adapted to confine a selected amount of the sample, the confinement zone comprising a base of surface area Sch and length Lch and a side wall of height Hch, the confinement zone in fluid communication with the input zone via a first channel of length Lin, height Hin and width Win, and
• an output zone adapted to discharge the carrier fluid medium and the sample in suspension in the carrier fluid medium, the output zone corresponding to a cylindrical output tank of diameter Dout, the output zone communicating with the confinement zone via a second channel of length Lout, height Hout and width Wout,
• the method comprises manufacturing the device as a function of the selected amount of the sample, the method comprising:
• A. forming the confinement zone to have the length Lch and the height Hch, the length Lch and the height Hch being a function of the selected amount of the sample and of a selected coverage area fraction ϕ of the base of the confinement zone by the sample;
• and
• B. forming the first channel to have the length Lin, the height Hin and the width Win and the second channel to have the length Lout, the height Hout and the width Wout, by:
• b1) calculating a sedimentation speed vsedi of a microparticle or a cell of the sample,
• b2) determining a speed vch of the carrier fluid medium in the confinement zone as a function of the sedimentation speed vsedi of the microparticle or the cell of the sample as per equation (1):
• v
• ch
• ≤
• v
• sedi
• ×
• H
• ch
• L
• ch
• (
• 1
• )
• b3) determining a head loss ΔZ, which is necessary for a flow of the carrier fluid medium in the confinement zone allowing for deposition of the sample within the confinement zone in the microfluidic device, as a function of a volume of the carrier fluid medium injected between the input zone and the output zone, and
• b4) determining geometric parameters of the microfluidic device from the head loss ΔZ and the speed vch of the carrier fluid medium, the geometric parameters including the length Lin, the height Hin and the width Win of the first channel, the diameter Din of the cylindrical input tank, the length Lout, the height Hout and the width Wout of the second channel, and the diameter Dout of the cylindrical output tank.