Methods and apparatus for the isolation and enrichment of circulating tumor cells
Embodiments in accordance with the present invention relate to methods and apparatuses for concentrating and isolating Circulating Tumor Cells (CTCs) from body fluids. One embodiment of the present invention includes a micro-fabricated or nano-fabricated device having channels configured for separating and excluding. Embodiments in accordance with the present invention utilize features that reduce the hydrodynamic pressure experienced by the cells during the separation, isolation and concentration processes, and therefore reduce the likelihood of cell lysis or other damage to the cells.
1. A method of isolating cancer cells, the method comprising:
passing a biofluid through a flow channel having a bend configured to impart a flow in a direction towards an aperture, wherein the flow channel is enclosed within walls of a microfluidic device and comprises the aperture configured to impede movement of a cancer cell while allowing flow of the biofluid through the aperture, wherein movement of the cancer cell is impeded by a cross-sectional shape of the aperture, wherein the cancer cell covers about 75% or less of a cross-sectional area of the aperture, whereby the cross-sectional area of the aperture reduces the fluid pressure applied to the cell.
2. The method of claim 1 further comprising diluting the biofluid prior to passage through the flow channel.
3. The method of claim 1 further comprising stabilizing the biofluid with a fixative prior to passage through the flow channel.
4. The method of claim 1 further comprising treating the biofluid with a material that binds preferentially to the cancer cell to assist in visualization of the cancer cells.
5. The method of claim 4 wherein the biofluid is treated with the material having fluorescent, magnetic, electroactive, bioactive, or photoactive properties.
6. The method of claim 1 further comprising visualizing the cancer cell with a microscope through a transparent wall of the channel.
7. The method of claim 1 further comprising:
collecting the cancer cell; and
treating the collected cancer cell with a material having fluorescent, magnetic, electroactive, bioactive, or photoactive properties.
8. The method of claim 7 wherein the material is configured to identify a subpopulation of cancer cells.
9. The method of claim 8 subpopulation of cancer cells comprises a putative cancer stem cell.
10. A method comprising:
collecting one or more cancer cells by flowing a sample of a biofluid through a first flow channel having a bend configured to impart a flow in a direction towards an aperture, wherein the first flow channel is enclosed in a microfluidic device and further comprises the aperture defined by a smallest dimension of a second flow channel, the smallest dimension smaller than a dimension of the one or more cancer cells, wherein the cross-sectional area of the aperture is configured to reduce the fluid pressure applied to the cancer cells, while allowing the cancer cell to cover about 75% or less of the cross-sectional area while fluid flows around the one or more cancer cells into the second flow channel; and
exposing the cancer cells to a material configured to bind preferentially thereto; and
counting a number of the collected cancer cells in order to evaluate a likelihood of metastasis.
11. The method of claim 10 wherein the cancer cells are exposed to the material prior to collection.
12. The method of claim 10 wherein the cancer cells are exposed to the material after the collection.
13. The method of claim 10 further comprising determining cancer diagnosis or prognosis based upon the number of cancer cells collected.
14. The method of claim 10 further comprising determining an effectiveness of cancer treatment based upon the number of cancer cells collected.