Microfluidic device for cell separation and uses thereof
The invention features methods for separating cells from a sample (e.g., separating fetal red blood cells from maternal blood). The method begins with the introduction of a sample including cells into one or more microfluidic channels. In one embodiment, the device includes at least two processing steps. For example, a mixture of cells is introduced into a microfluidic channel that selectively allows the passage of a desired type of cell, and the population of cells enriched in the desired type is then introduced into a second microfluidic channel that allows the passage of the desired cell to produce a population of cells further enriched in the desired type. The selection of cells is based on a property of the cells in the mixture, for example, size, shape, deformability, surface characteristics (e.g., cell surface receptors or antigens and membrane permeability), or intracellular properties (e.g., expression of a particular enzyme).
1. A method of diagnosing cancer in a patient, the method comprising:
flowing a blood sample from a patient through a device comprising a plurality of obstacles on a substrate, wherein the obstacles are each coupled to one or more binding moieties that selectively bind to an epithelial cell or a tumor cell indicative of cancer in the patient, wherein said flowing selectively enriches said epithelial cells or tumor cells by a factor of at least 1,000 in said blood sample.
2. The method of claim 1 , wherein said blood sample is flowed at a rate of at most 15 μl/sec.
3. The method of claim 1 , wherein said device has sensitivity or specificity greater than 75%.
4. The method of claim 1 , wherein said device retains at least 60% of said epithelial cells or tumor cells in said blood sample.
5. The method of claim 1 , wherein said device enriches said epithelial cells or tumor cells in said blood sample by a factor of at least 100,000.
6. The method of claim 1 , further comprising performing nucleic acid analysis on said enriched epithelial cells or tumor cells.
7. The method of claim 5 , further comprising performing nucleic acid analysis on said enriched epithelial cells or tumor cells.
8. The method of claim 1 , further comprising using fluorescence in situ hybridization (FISH) analysis to identify epithelial cells or tumor cells present in the enriched cell population.
9. The method of claim 5 , further comprising using fluorescence in situ hybridization (FISH) analysis to identify epithelial cells or tumor cells present in the enriched cell population.
10. The method of claim 1 , wherein the binding moiety is an antibody.
11. The method of claim 10 , wherein the antibody selectively binds to a cell surface receptor.
12. The method of claim 1 , wherein the distance between obstacles varies in a flow direction.
13. The method of claim 1 , wherein the obstacles are arranged in an equilateral triangular array.
14. The method of claim 1 , wherein the flowing comprises flowing at a flow rate of 1.0 to 20 μl/sec.
15. The method of claim 1 , wherein the flowing comprises flowing at a flow rate that provides a wall shear stress on cells less than 1 dyne/cm 2 .
16. The method of claim 1 , wherein red blood cells are not enriched in said blood sample.
17. The method of claim 1 , wherein the plurality of obstacles comprises an array that comprises a first subarray and a second subarray, and wherein the obstacles in the first subarray have a different feature than the obstacles in the second subarray.
18. The method of claim 13 , wherein the obstacles in the equilateral triangular array of obstacles are arranged in a staggered array.
19. The method of claim 1 , wherein the epithelial cells or tumor cells are living cells.
20. The method of claim 1 , wherein the obstacles are spaced 10 to 100 microns apart.
21. The method of claim 1 , wherein the obstacles are arranged in rows aligned normal to a direction of flow of the blood sample through the device and obstacles in one row are shifted in a direction normal to the flow with respect to obstacles in an adjacent row.
22. The method of claim 1 , wherein the device is configured in the form of a flow chamber, and wherein the substrate forms a bottom surface of the flow chamber.
23. The method of claim 22 , wherein the device further comprises a top surface.
24. The method of claim 22 , wherein the device comprises a transparent window.
25. The method of claim 23 , wherein the obstacles contact both the top and bottom surfaces of the flow chamber.
26. The method of claim 23 , wherein the obstacles are distributed on the bottom surface of the flow chamber and have a height that leaves a gap between top ends of the obstacles and the top surface.