Cell sodding method and apparatus
Tissue engineering methods and biochamber apparatus are provided for making tissue grafts for implantation into a patient. The methods include applying a sustained low magnitude pressure gradient transmurally across a permeable scaffold material using a media containing cells, preferably microvascular epithelial cells, to be deposited on the scaffold for the production of tissue grafts, preferably vascular grafts, to promote accelerated adhesion and maturation of cells on the scaffold material. Biochambers for preparing tubular tissue grafts are provided which contain connectors for holding a graft substrate, proximal and distal tubing for connection to an optional perfusion system, and structure for switching between transmural flow of a cell suspension across the graft substrate and translumenal flow through the lumen of the graft.
1. A method of preparing a tissue graft for implantation into a patient, comprising:
providing a porous substrate having a first side and a second side; and
applying a transmural flow of a suspension of cells across the wall of the substrate from the first side to the second side, wherein there is a defined transmural pressure gradient of about 10 to about 60 mmHg between the first side and the second side, and wherein the transmural flow and the defined pressure are sustained for a duration sufficient to adhere the cells to the substrate, said duration being at least 5 minutes.
2. The method of claim 1 , wherein the substrate has a tubular configuration for a vascular tissue graft, and wherein one of the first or second sides is the inner side of the tubular substrate, and the other of the first or second sides is the outer side of the tubular substrate.
3. The method of claim 1 , wherein the pressure gradient is from about 10 mmHg to about 55 mmHg.
4. The method of claim 1 , wherein the pressure gradient is from about 35 mmHg to about 50 mmHg.
5. The method of claim 1 , wherein the pressure gradient is about 50 mmHg.
6. The method of claim 1 , wherein the duration is about 7 minutes to about 1 hour.
7. The method of claim 1 , wherein the cells are endothelial cells.
8. The method of claim 1 , wherein the cells are microvascular endothelial cells.
9. The method of claim 8 , wherein the microvascular endothelial cells are derived from adipose tissue.
10. The method of claim 9 , further comprising harvesting the adipose tissue from said patient.
11. The method of claim 9 , wherein the cells comprise a mixture of microvascular endothelial cells and adult stem cells.
12. The method of claim 11 , wherein the cells are autologous.
13. The method of claim 1 , wherein the substrate comprises a material selected from the group consisting of elastin, ePTFE, collagen, polyurethane, polypropylene, polyethylene, polyamides, nylon, polyethylene terephthalate, polycarbonate, and silicone.
14. The method of claim 2 , further comprising applying translumenal flow through the tubular graft after the cells have adhered to the substrate and before implantation of the graft into the patient.
15. The method of claim 14 , wherein the translumenal flow is at a physiological flow rate.
16. The method of claim 1 , wherein the graft is pretreated with a material selected from the group consisting of protein and plasma.
17. The method of claim 16 , wherein the graft is pretreated with albumin.
18. The method of claim 1 , wherein the graft is rotated longitudinally at least once during transmural flow.