Cell culture method using bone marrow-like structure, and porous polyimide film for healing bone injury site

1. A method of healing a bone injury site,

including applying a porous polyimide film to an affected area of bone injury of a patient in need of healing the bone injury site,

wherein the porous polyimide film has a three-layer structure consisting of an A-surface layer having a plurality of pores, a B-surface layer having a plurality of pores, and a macro-void layer sandwiched between the two surface layers,

a mean pore size in the A-surface layer is smaller than a mean pore size in the B-surface layer, and

the macro-void layer has a partition bonded to the A-surface layer and the B-surface layer, and a plurality of macro-voids surrounded by the partition, the A-surface layer, and the B-surface layer,

wherein the bone injury is a fracture or bone loss,

wherein cells have not been supported on the porous polyimide film, or mammal-derived bone marrow cells have been supported on the porous polyimide film beforehand; and

wherein the A-surface layer of the porous polyimide film is applied to the affected area of bone injury of the patient.

2. The method according to claim 1 , wherein the bone injury is a fracture.

3. The method according to claim 1 , wherein the bone injury is bone loss.

4. The method according to claim 1 , including transplantation of the porous polyimide film into the body in such a manner that the porous polyimide film is in contact with an affected area of bone injury.

5. The method according to claim 1 , wherein the porous polyimide film is a porous polyimide film including a polyimide obtained from a tetracarboxylic dianhydride and a diamine.

6. The method according to claim 5 , wherein the porous polyimide film is a colored porous polyimide film obtained by forming a polyamic acid solution composition including a polyamic acid solution obtained from a tetracarboxylic dianhydride and a diamine, and a coloring precursor, and then heat treating it at 250° C. or higher.

7. The method according to claim 1 , including transplantation of the porous polyimide film into the body in such a manner that is in contact with the affected area of bone injury.

8. The method according to claim 1 , wherein the film thickness of the porous polyimide film is no greater than 100 micrometers.

9. The method according to claim 1 , wherein the surface of the porous polyimide film is treated by a step of modifying its physical properties.

10. The method according to claim 9 , wherein the step of modifying the physical properties of the surface of the porous polyimide film is selected from the group consisting of a step of alkali treatment of the surface of the porous polyimide film, a step of calcium treatment, a step of covering with a biocompatible material, and a combination of any of these steps.

11. The method according to claim 10 , wherein the biocompatible material is selected from the group consisting of collagen, fibronectin, laminin, polylysine, polylactide, polyglycolide, polycaprolactone, polyhydroxybutyrate, polylactide-co-caprolactone, polycarbonate, biodegradable polyurethane, polyether ester, polyesteramide, hydroxyapatite, collagen/β-TCP complex, and combinations of the foregoing.

12. The method according to claim 1 , wherein mammal-derived bone marrow cells have been supported on the porous polyimide film beforehand.

13. The method according to claim 1 , wherein cells have not been supported on the porous polyimide film.