Device for forming drops in a microfluidic circuit
AssigneesCentre National De La Recherche Scientifique, Ecole Polytechnique
InventorsCharles Baroud, Rémi Dangla
Life of this patent
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Abstract
The invention relates to a device (1) for forming droplets in a microfluidic circuit, the device comprising a chamber (3) containing a first fluid and defined by two opposite walls (10, 11) that diverge relative to each other in at least one given direction, and a microchannel (8) containing a second fluid and leading into a zone of said chamber (3) that is upstream relative to the given direction, the outlet of the microchannel (8) into the chamber (3) constituting an enlargement in the flow section for the second fluid, and the enlargement giving rise to droplets (14) of the second fluid forming within the first fluid.
Claims28
A method of forming a droplet of a second fluid in a first fluid contained in a microfluidic circuit, the method consisting in;
- bringing the second fluid to an inlet of a chamber containing the first fluid, the inlet of the chamber comprising two opposite walls of the chamber that diverge inside the chamber,
- urging the second fluid into the inlet of the chamber to form a finger of the second fluid projecting into the chamber and attached to the second fluid, the finger enlarging progressively between the two opposite diverging walls of the chamber, the finger being flattened between said opposite diverging walls, until its upstream end becomes detached from the delivery of the second fluid, to form the droplet,
- wherein said microfluidic circuit does not comprise any additional channel conveying a flow of said first fluid for shearing the second fluid and forming said droplet.
A method of forming a droplet of a second fluid in a first fluid contained in a microfluidic circuit, the method consisting in:
- bringing the second fluid to an inlet of a chamber containing the first fluid, the inlet of the chamber comprising two opposite walls of the chamber that diverge inside the chamber, and
- urging the second fluid into the inlet of the chamber to form a finger of said second fluid projecting into the chamber, the finger enlarging progressively between the two opposite diverging walls of the chamber, the finger being flattened between said opposite diverging walls, until its upstream end becomes detached from the delivery of the second fluid, to form the droplet,
- wherein the flow rate of the first fluid in the chamber is substantially zero.
A method of forming a droplet of a second fluid in a first fluid contained in a microfluidic circuit, the method consisting in:
- bringing the second fluid to an inlet of a chamber containing the first fluid through a microchannel, the inlet of the chamber comprising two opposite walls that diverge inside the chamber, and in
- urging the second fluid into the inlet of the chamber to form a finger of said second fluid projecting into the chamber and attached to the second fluid contained in the microchannel, said finger of second fluid being subjected to two opposing forces due to surface tension:
- a first force being due to a surface energy gradient tending to extract the second fluid from the microchannel,
- a second force corresponding to capillary force being opposite to said first force and tending to keep the finger attached to the second fluid contained in the microchannel,
- the finger enlarging progressively between the two opposite diverging walls of the chamber, the finger being flattened between said opposite diverging walls, until its upstream end becomes detached from the second fluid contained in the microchannel to form a droplet, when the first force become greater than the second force.
A microfluidic circuit for forming droplets of a second fluid in a first fluid, wherein the micro fluidic circuit comprises:
- a chamber configured to contain a first fluid, said chamber comprising two opposite longitudinal walls that diverge in said chamber relative to each other in at least one given direction, and
- a microchannel for containing a second fluid that leads into a zone of said chamber that is upstream relative to the given direction, through an inlet, wherein the inlet into the chamber includes an increase in the flow section for the second fluid in two directions perpendicular to said given direction,
- wherein said micro fluidic circuit does not comprise any additional channel configured for conveying a flow of said first fluid into said microchannel or said zone of said chamber, and configured for shearing the second fluid into droplets.
Dependencies are inferred from the claim text.