Bump array device having asymmetric gaps for segregation of particles

A bump array device for segregating particles by size, the device comprising

• a body defining a microfluidic flow channel for containing fluid flow in a first direction and a second direction and
• an array of obstacles disposed within and extending across the flow channel,
• the obstacles being arranged in rows and columns, wherein the rows define an array direction that differs from the first direction by a tilt angle (c) that has a magnitude greater than zero;
• the obstacles in columns defining gaps between themselves through which the fluid can flow in the first direction generally transversely with respect to the columns and through which the fluid can flow in the second direction generally transversely with respect to the column;
• and
• the obstacles being shaped such that the critical particle size for particles passing through the gap in the first direction is different than the critical particle size for particles passing through the gap in the second direction.

A method of segregating particles, the method comprising inducing movement of a fluid in a first direction in a flow channel having a multiplicity of obstacles disposed therein and extending thereacross,

• the fluid having the particles suspended therein,
• the obstacles being arranged in rows and columns, wherein the rows define an array direction that differs from the first direction by a tilt angle (ε) that has a magnitude greater than zero;
• the obstacles in columns defining gaps between themselves through which the fluid can flow generally transversely with respect to the columns,
• the obstacles being shaped such that the surfaces of two obstacles defining a gap are asymmetrically oriented about the plane that extends through the center of the gap and that is parallel to the first direction,
• whereby the velocity profile of fluid flow through the gap is asymmetrically oriented about the plane and the critical particle size for particles passing through the gap adjacent to one of the obstacles is different than the critical particle size for particles passing through the gap adjacent to the other of the obstacles,
• and whereby particles having a size greater than at least one of i) the critical particle size for particles passing through the gap adjacent to one of the obstacles and ii) the critical particle size for particles passing through the gap adjacent to the other of the obstacles are segregated from other particles.

A method of segregating particles, the method comprising inducing discrete, alternate movement of a fluid in a first direction and a second direction, in a flow channel having a multiplicity of obstacles disposed therein and extending thereacross,

• the fluid having the particles suspended therein,
• the obstacles being arranged in rows and columns, wherein the rows define an array direction that differs from the first direction by a tilt angle (ε) that has a magnitude greater than zero;
• the obstacles in columns defining gaps between themselves through which the fluid can flow in the first direction generally transversely with respect to the columns and through which the fluid can flow in the second direction generally transversely with respect to the column;
• and
• the obstacles being shaped such that the critical particle size for particles passing through the gap in the first direction is different than the critical particle size for particles passing through the gap in the second direction,
• whereby particles intermediate in size between i) the critical particle size for particles passing through the gap in the first direction and ii) the critical particle size for particles passing through the gap in the second direction are separated from other particles.