METHODS FOR PROCESSING BIOLOGICAL TISSUE

• US 20060207031A1
• Filed: 06/06/2006
• Published: 09/21/2006
• Est. Priority Date: 01/11/2005
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Cunanan, Crystal M., Cambron, Ronald E., Ochoa, Alexandro
• Granted Patent: US 7,622,276 B2
• Time in Patent Office: Days
• US Class Current: 8/94.110
• CPC Class Codes: A01N 1/02 Preservation of living parts
• CPC Class Codes: A01N 1/0226 Physiologically active agents, i.e. substances affecting physiological processes of cells and tissue to be preserved, e.g. anti-oxidants or nutrients

Abstract

A method for processing biological tissue used in biological prostheses includes providing a tissue procurement solution formed from a phosphate buffered saline (PBS) solution and a chelating agent. The tissue is transferred from the tissue procurement solution and undergoes chemical fixation. The fixed tissue is then immersed in a series of fresh bioburden reduction process (BRP) solutions to extract phospholipids. The tissue procurement solution reduces the bioburden on the stored tissue and preserves tissue architecture by minimizing tissue swelling. The tissue procurement solution further reduces calcium from the incoming water and/or tissue, and inhibits enzymes that digest the collagen matrix. The serial immersion of the tissue in the fresh bioburden solutions ensures optimal extraction of phospholipids thereby mitigating subsequent calcification of the tissue.

Claims

1. A method for storing harvested tissue used in biological prostheses comprising the steps of:

providing a solution containing a mixture of phosphate buffered saline (PBS) solution having a concentration of at least 100 mM and a chelating agent; and

immersing the harvested tissue in the solution.

2. The method of claim 1, wherein the solution has an osmolarity value within the range of 290-310 mOsm.

3. A method for processing fixed biological tissue comprising the steps of:

(a) immersing the fixed biological tissue in a first fresh bioburden reduction process (BRP) solution;

(b) heating the first fresh BRP solution to a temperature of about 37°

C.;

(c) removing the fixed biological tissue from the fresh BRP solution;

(d) immersing the fixed biological tissue in a next fresh BRP solution; and

(e) heating the next fresh BRP solution to a temperature of about 37°

C.

4. The method of claim 3, further comprising the steps of repeating steps (c), (d), and (e) one or more times.

5. The method of claim 3, wherein, in steps (b) and (e), the BRP solution is heated for a period of time between four and sixteen hours.

6. The method of claim 3, wherein the total time the fixed tissue is exposed to BRP solution is no more than about twenty-four hours.

7. The method of claim 3, wherein the BRP solution comprises an aqueous mixture of sodium chloride, potassium phosphate monobasic, sodium phosphate dibasic heptahydrate, glutaraldehyde, and polyoxyethylene sorbitan monoleate.

8. The method of claim 3, wherein phospholipids are soluble in each BRP solution.

9. A method for processing biological tissue, comprising:

immersing tissue in a mixture of phosphate buffered saline (PBS) solution having a concentration of at least 50 mM and a chelating agent;

transferring the tissue to a phosphate buffered fixation solution;

cutting a portion of the tissue into a desired shape;

transferring the cut tissue portion into a series of fresh bioburden reduction process (BRP) solutions, wherein each fresh BRP solution is heated for a period of time.

10. The method of claim 9, further comprising transferring the cut tissue portion from the fresh BRP solution to a terminal sterilant solution.