Decellularisation of matrices

1. A method of preparing donor biological material for implantation consisting essentially of:

(i) incubating the donor biological material with a buffer solution at a mild alkaline pH, wherein the buffer solution comprises a proteolytic inhibitor;

(ii) incubating the donor biological material with an anionic detergent at a mild alkaline pH at a concentration which is sufficient to effect decellularization but which maintains the histoarchitecture of the donor biological material, wherein said incubation is the sole incubation step with the detergent in said method of preparing the donor biological material for implantation and said anionic detergent is the sole detergent agent in the method;

(iii) washing the donor biological material with a buffer solution at a mild alkaline pH, wherein the buffer solution comprises a proteolytic inhibitor;

(iv) washing the donor biological material with a buffer solution at a mild alkali pH in the absence of a proteolytic inhibitor;

(v) incubating the donor biological material with one or more enzymes selected from the group consisting of DNase Type I, DNase Type II, and/or RNase; and optionally

(vi) placing the donor biological material in a cryoprotectant medium.

2. The method according to claim 1 , wherein the buffer is hypotonic or isotonic.

3. The method according to claim 1 , further comprising cryopreserving the donor biological material in a cryogen.

4. The method according to claim 3 , wherein the cryogen is liquid nitrogen.

5. The method according to claim 1 , wherein the proteolytic inhibitor is ethylene diamine tetraacetic acid (EDTA), Aprotinin or a combination thereof.

6. The method according to claim 5 , wherein the EDTA is used at a concentration in the region of 1 to 100 mM or 0.01-1.0% (w/v).

7. The method according to claim 5 , wherein EDTA is used at a concentration of 10 mM or 0.1% (w/v).

8. The method according to claim 5 , wherein Aprotinin is used at a concentration range of 1-100 KIU.

9. The method according to claim 5 , wherein Aprotinin is used at 10 KIU.

10. The method according to claim 1 , wherein the mild alkaline conditions (i) are in the pH range of above 7.0 and up to pH 10.0.

11. The method according to claim 10 , wherein the pH is 8.0.

12. The method according to claim 1 , wherein the incubation period of (i) is from 8 to 20 hours.

13. The method according to claim 12 , wherein the incubation period is 14 hours.

14. The method according to claim 1 , wherein the anionic detergent is sodium dodecyl sulphate (SDS) or sodium deoxycholate.

15. The method according to claim 14 , wherein SDS is used at a concentration in a range from 0.03% (w/v) to 0.1% (w/v).

16. The method according to claim 14 , wherein sodium deoxycholate is used at a concentration in a range from 0.5% (w/v) to 2.0% (w/v).

17. The method according to claim 1 , wherein the incubation period of (ii) is from 20 to 28 hours.

18. The method according to claim 17 , wherein the incubation period is 24 hours.

19. The method according to claim 1 , wherein the alkaline conditions of (ii) are in the pH range of above 7.0 to pH 10.0.

20. The method according to claim 19 , wherein the pH is 8.0.

21. The method according to claim 1 , wherein the washing of (iii) comprises multiple washes with iris buffered saline containing protease inhibitors and/or multiple washes with iris buffered saline without the protease inhibitors.

22. The method according to claim 21 , wherein the buffer is 0.15 M NaCl, 0.05 M tris in distilled water with or without EDTA and Aprotinin.

23. The method according to claim 1 , wherein the alkaline conditions of (iii) are in the pH range of above 7.0 to pH 10.0.

24. The method according to claim 23 , wherein the pH is 8.0.

25. The method according to claim 1 , wherein the incubation of (iv) is for 4-6 hours at 37° C.

26. The method according to claim 1 , wherein DNase I is used at a concentration in the range of 5-100 μg/ml and RNase is used at a concentration in the range of 0.1-10 μg/ml.

27. The method according to claim 1 , wherein the donor biological material is prepared in (vi) for storage by placement in a cryoprotectant comprising Dulbecco's modified eagles medium (DMEM) containing between 10-20% (v/v) fetal bovine selum (FBS) and 5-15% (v/v) dimethyl sulphoxide (DMSO).

28. A method of decellularizing a donor tissue matrix using an anionic detergent at a concentration sufficient to effect decellularization, but at a concentration which maintains a histoarchitecture of a heart valve extracellular matrix, the sole anionic detergent being used in conjunction with EDTA and Aprotinin protease inhibitors.

29. A method of preparing donor biological material for implantation consisting essentially of:

(i) incubating the donor biological material with a buffer solution at a mild alkaline pH, wherein the buffer solution comprises a proteolytic inhibitor selected from the group consisting of ethylene diamine tetraacetic acid (EDTA), Aprotinin and a combination thereof;

(ii) incubating the donor biological material with an anionic detergent at a mild alkaline pH at a concentration which is sufficient to effect decellularization but which maintains the histoarchitecture of the donor biological material, wherein said incubation is the sole incubation step with the detergent in said method of preparing the donor biological material for implantation;

(iii) washing the donor biological material with a buffer solution at a mild alkaline pH wherein the buffer solution comprises a proteolytic inhibitor selected from the group consisting of ethylene diamine tetraacetic acid (EDTA), Aprotinin and a combination thereof;

(iv) washing the donor biological material with a buffer solution at a mild alkali pH in the absence of a proteolytic inhibitor;

(v) incubating the donor biological material with one or more enzymes selected from the group consisting of DNase Type I, DNase Type II, and/or RNase; and

(vi) cryopreserving the donor biological material.