Particulate tissue graft with components of differing density and methods of making and using the same

1. A method for preparing a mixture of bioresorbable particulate matter, comprising:

(a) providing a first sheet of bioresorbable material comprising a native extracellular matrix comprising epithelial basement membrane and tunica propria and having a first density and a first rate of resorption, and,

milling said first sheet into a first plurality of bioresorbable particles;

(b) providing a second sheet of a bioresorbable material comprising another extracellular matrix different than the extracellular matrix material of the first sheet and having a second density and a second rate of resorption, and,

milling said second sheet into a second plurality of bioresorbable particles;

(c) providing a predetermined quantity of said first plurality of bioresorbable particles and a predetermined quantity of said second plurality of bioresorbable particles; and

(d) mixing said predetermined quantity of said first plurality of bioresorbable particles with a predetermined quantity of said second plurality of bioresorbable particles,

wherein the second density is 150%-500% of the first density.

2. The method of claim 1 , further comprising compressing or laminating the second sheet prior to milling to increase its density relative to the first sheet.

3. The method of claim 1 further comprising lyophilizing the first sheet prior to milling to reduce its density relative to the second sheet.

4. A method for preparing a mixture of bioresorbable particulate matter having differing densities comprising:

providing a first sheet of bioresorbable material comprising a native extracellular matrix comprising epithelial basement membrane and tunica propria and having a first density, and,

compressing a portion of said sheet such that said portion comprises a second density; providing a second sheet of bioresorbable material comprising a native extracellular matrix;

joining said first sheet to said second sheet to form a multilaminate sheet, and

milling said multilaminate sheet into a plurality of bioresorbable particles, wherein said mixture of bioresorbable particles promotes tissue restoration and repair when implanted at a tissue site in a mammalian patient, wherein the second density of the first sheet is at least 150% of the first density.

5. A method of preparing a mixture of bioresorbable extracellular matrix particles, comprising:

preparing a plurality of bioresorbable particles from a native extracellular matrix comprising epithelial basement membrane and tunica propria each having the same density;

dividing the plurality of bioresorbable particles into a first group and a second group;

coating the first group of said plurality of bioresorbable particles with a coating comprising a material selected from the group consisting of an extracellular matrix, polyglycolic acid, hyaluronic acid, collagen, or combinations thereof, said coating having a first density;

coating the second group of said plurality of bioresorbable particles with a coating comprising a material selected from the group consisting of an extracellular matrix, polyglycolic acid, hyaluronic acid, collagen, or combinations thereof, said coating having a second density;

mixing said first group of bioresorbable particles with said second group of bioresorbable particles to form a mixture of bioresorbable particles, wherein said mixture of bioresorbable particles promotes tissue restoration and repair when implanted at a tissue site in a mammalian patient, and wherein the second density is 150%-500% of the first density.

6. The method of claim 4 wherein said first sheet of bioresorbable material and said second sheet of bioresorbable material comprises non-cross-linked extracellular matrix.

7. The method of claim 5 wherein said native extracellular matrix is non-cross-linked.

8. The method of claim 1 wherein said first sheet and said second sheet comprise non-cross-linked extracellular matrix.

9. The method of claim 1 further comprising providing a biologically active component selected from the group consisting of epidermal growth factor, TGF-alpha, TGF-beta, fibroblast growth factor, platelet derived growth factor, vascular endothelial growth factor, insulin-like growth factor, keratinocyte growth factor, bone morphogenic protein, pharmaceutical agents, DNA vectors and combinations thereof.

10. The method of claim 1 wherein the density of the second plurality of bioresorbable particles is at least 150% of the density of the first plurality of bioresorbable particles and wherein the first rate of resorption is at least 1.5 times that of the second rate of resorption.