Method of enriching stem and/or progenitor cells

1. A method of enriching cancer stem cells comprising:

a first growing of a heterogeneous cell sample comprising cancer stem cells on a first substrate that is hydrophobic and has an elastic modulus less than about 100 MPa;

a first recovering of the heterogeneous cell sample from the first substrate;

a second growing of the recovered heterogeneous cell sample on a second substrate having an elastic modulus higher than the elastic modulus of the first substrate to produce a subpopulation of nonadherent cells and a subpopulation of adherent cells; and

a second recovering of the nonadherent cell subpopulation from the second substrate, which is enriched for cancer stem cells.

2. The method according to claim 1 , further comprising: repeating said second growing and said second recovering using the nonadherent cell subpopulation to obtain further enriched subpopulations of cancer stem cells.

3. The method according to claim 1 , wherein the elastic modulus of the first substrate is about 100 Pa to about 50 MPa.

4. The method according to claim 1 , wherein the elastic modulus of the first substrate is about 1 kPa to about 30 MPa.

5. The method according to claim 1 , wherein the first substrate has a surface energy of less than about 30 dynes/cm, exhibits an air-water contact angle that is greater than about 80 degrees, or both.

6. The method according to claim 1 , wherein the first substrate is a natural or synthetic rubber, a silicone, polydimethylsiloxane (PDMS), a low density poly(ethylene-covinyl acetate), a low density polyethylene, a low density polyurethane, fluorinated versions thereof, or copolymers thereof.

7. The method according to claim 1 , wherein the second substrate has an elastic modulus of at least about 500 MPa.

8. The method according to claim 1 , wherein the second substrate has a surface energy of greater than about 40 dynes/cm, exhibits an air-water contact angle that is less than about 50 degrees, or both.

9. The method according to claim 1 , wherein the second substrate is glass or an oxygen plasma-treated polymer selected from the group consisting of polystyrene, polystyrene/acrylonitrile copolymers, high density polyurethane, high and medium density polyethylene, polyamide, polypropylene, and polyvinylchloride.

10. The method according to claim 1 , wherein the first substrate is PDMS and the second substrate is polystyrene.

11. The method according to claim 1 , wherein said first recovering is carried out by aspiration.

12. The method according to claim 1 , wherein the enriched subpopulations are phenotypically distinct from the subpopulation of adherent cells.