Systems and methods for three-dimensional extraction of target particles ferrofluids

1 . A method for extracting particles within a ferrofluid medium, the method comprising:

flowing a single flow into and through a single microfluidic channel via an inlet of the single microfluidic channel, the single microfluidic channel having first and second ends defining a straight line that delineates a first direction, the single flow comprising a mixture of a ferrofluid medium and two or more types of target particles, the single microfluidic channel including:

a second portion spaced downstream from the inlet,

a first side spaced away from a second side and comprising a width of the single microfluidic channel, and

a third side spaced away from a fourth side and comprising a height of the single microfluidic channel,

wherein the single flow flows through the single microfluidic channel in the first direction from the inlet to the second portion;

applying a first magnetic field across the width of the microfluidic channel so as to effect an indirect force on the at least two types of different target particles within the ferrofluid medium so as to focus each of the at least two types of target particles into at least two corresponding streamlines across a width region and a height region of the single microfluidic channel, such that a first of the at least two corresponding streamlines for at least one type of the at least two types of target particles flows along the third side toward an extraction opening,

wherein the extraction opening comprises a single opening in the second portion that is parallel to the single flow flowing in the first direction; and

diverting the first streamline for the at least one type of the at least two types of target particles through the extraction opening, wherein the first streamline includes an exit velocity from the extraction opening in a second direction that is perpendicular to the first direction, and the remainder of the single flow continues along the single microfluidic channel past the extraction opening in the first direction.

2 . The method of claim 1 , wherein a type of particles corresponds to at least one of a size, shape, mass, and charge of one or more particles.

3 . The method of claim 1 , wherein a first type of the at least two types of target particles comprises at least one of target moieties and target biological cells.

4 . The method of claim 1 , wherein applying the first magnetic field includes applying a magnetic field through at least one of current-carrying electrodes and magnets.

5 . The method of claim 1 , further comprising adjusting the exit velocity of the first streamline by configuring the first magnetic field to effect forces on the flow affecting the exit velocity.

6 . The method of claim 1 , further comprising adjusting the exit velocity of the first streamline of target particles by configuring the size of the extraction opening to increase velocity.

7 . The method of claim 1 , further comprising adjusting the exit velocity of the first streamline of target particles by controlling the flow resistance from the extraction opening.

8 . The method of claim 1 , further comprising adjusting the exit velocity of the first streamline of target particles by providing at least one of a pressure sink and a flow sink arranged downstream of the extraction opening.

9 . The method of claim 1 , wherein the inlet comprises a single inlet of the single microfluidic channel.

10 . The method of claim 1 , further comprising extracting at least one of the at least two types of target particles via the extraction opening.

11 . The method of claim 1 , wherein the first of the at least two corresponding streamlines for one type of the at least two types of target particles interacts with the third side of the microfluidic channel by rolling along the third side.

12 . A method for extracting particles within a ferrofluid medium, the method comprising:

flowing a single flow into and through a single microfluidic channel via an inlet of the single microfluidic channel, the single microfluidic channel having first and second ends defining a straight line that delineates a first direction, the single flow comprising a mixture of a ferrofluid medium and one or more types of target particles, the single microfluidic channel including:

a second portion spaced downstream from the inlet,

a first side spaced away from a second side and comprising a width of the single microfluidic channel, and

a third side spaced away from a fourth side and comprising a height of the single microfluidic channel,

wherein the single flow flows through the single microfluidic channel in the first direction from the inlet to the second portion;

and

applying a first magnetic field across the width of the microfluidic channel so as to effect an indirect force on the at least one type of target particles within the ferrofluid medium so as to focus the at least one type of target particles into a streamline across a width region and a height region of the single microfluidic channel, such that the streamline flows and interacts with the third side toward an extraction opening,

wherein the extraction opening comprises a single opening in the second portion that is parallel to the single flow flowing in the first direction; and

directing the streamline through the extraction opening in a second direction that is perpendicular to the first direction, wherein the remainder of the single flow continues along the single microfluidic channel past the extraction opening in the first direction.

13 . The method of claim 12 , further comprising extracting the at least one type of target particles via the extraction opening.

14 . The method of claim 12 , wherein the streamline interacts with the third side of the microfluidic channel by rolling along the third side.

15 . A method for extracting particles within a ferrofluid medium, the method comprising:

providing a microfluidic channel comprising:

a first side spaced away from a second side and defining a width of the microfluidic channel,

a third side spaced away from a fourth side and defining a height of the microfluidic channel, and

first and second portions, wherein the first portion comprises an inlet, and the second portion is spaced downstream from the inlet and comprises an extraction opening comprising a single opening on the third side;

flowing a mixture into the inlet of the microfluidic channel, wherein

the mixture comprises a ferrofluid medium and two or more types of target particles, and

the mixture flows through the microfluidic channel in a first direction delineated by a straight line from the first portion to the second portion;

applying a magnetic field across the width of the microfluidic channel to focus each of the at least two types of target particles into at least two corresponding streamlines across a width region and a height region of the microfluidic channel, such that a first streamline of the at least two corresponding streamlines comprises at least one type of the target particles and flows along the third side towards the extraction opening; and

diverting the first streamline through the extraction opening, wherein the first streamline includes an exit velocity from the extraction opening in a second direction that is perpendicular to the first direction, further wherein the remainder of the mixture continues along the microfluidic channel past the extraction opening in the first direction.

16 . The method of claim 15 , wherein the first streamline interacts with the third side of the microfluidic channel by rolling along the third side.

17 . The method of claim 15 , further comprising extracting at least one of the at least two types of target particles via the extraction opening.