Tissue engineered cartilage, method of making same, therapeutic and cosmetic surgical applications using same

Abstract

Cartilage has been constructed using biodegradable electrospun polymeric scaffolds seeded with chondrocytes or adult mesenchymal stem cells. More particularly engineered cartilage has been prepared where the cartilage has a biodegradable and biocompatible nanofibrous polymer support prepared by electrospinning and a plurality of chondocytes or mesenchymal stem cells dispersed in the pores of the support. The tissue engineered cartilages of the invention possess compressive strength properties similar to natural cartilage. Methods of preparing engineered tissues, including tissue engineered cartilages, are provided in which an electrospun nanofibrous polymer support is provided, the support is treated with a cell solution and the polymer-cell mixture cultured in a rotating bioreactor to generate the cartilage. The invention provides for the use of the tissue engineered cartilages in the treatment of cartilage degenerative diseases, reconstructive surgery, and cosmetic surgery.

1 . A tissue engineered cartilage, comprising
 a nanofibrous polymer support comprising a plurality of polymer nanofibers; and   a plurality of chondrocytes dispersed throughout the polymer support, wherein the tissue engineered cartilage has a peak compressive stress (Young's modulus) of greater than 250 MPa.   
     
     
         2 - 13 . (canceled) 
     
     
         14 . A method of preparing tissue engineered cartilage comprising
 preparing a nanofibrous biocompatible polymer support;   contacting a suspension of cells with the surface of the support to form a polymer matrix having cells dispersed therein;   culturing the cell-polymer matrix in a bioreactor with a culture medium under conditions conducive to growth of chondocytes into a tissue engineered cartilage.   
     
     
         15 . A method of preparing tissue engineered cartilage comprising
 preparing an nanofibrous biocompatible polymer support;   expanding the nanofibrous polymer support thereby increasing interfiber distance;   contacting a suspension of cells with the support to form a polymer matrix having cells dispersed therein;   compressing the cell-polymer matrix to create cell-cell contact and cell-polymer contact;   culturing the compressed cell-polymer matrix in a bioreactor with a culture medium under conditions conducive to growth of chondocytes into a tissue engineered cartilage having a peak compressive stress (Young's modulus) of greater than 250 MPa.   
     
     
         16 . The method of  claim 15 , wherein the cells are stem cells or chondocytes. 
     
     
         17 . (canceled) 
     
     
         18 . The method of  claim 15 , wherein the culture medium is substantially free of serum. 
     
     
         19 . The method of  claim 15 , wherein the nanofibrous polymer support is dimensionally stable throughout the culturing step. 
     
     
         20 . The method of  claim 15 , wherein the nanoporous biodegradable polymer comprises polymer nanofibers having a diameter of less than 1 micron. 
     
     
         21 . The method of  claim 15 , wherein the polymer nanofibers have a diameter of between 100 nm and 1 micron. 
     
     
         22 . The method of  claim 15 , wherein the polymer nanofibers have a substantially uniform diameter. 
     
     
         23 . The method of  claim 15 , wherein the nanofibrous polymer support comprises a non-woven mat of electrospun nanofibers having a diameter of less than 1 micron. 
     
     
         24 . The method of  claim 23 , wherein the nanofibers of the non-woven mat is randomly oriented. 
     
     
         25 . The method of  claim 23 , wherein the nanofibrous polymer support is composed of at least one biodegradable polyester or blend thereof. 
     
     
         26 . The method of  claim 23 , wherein the nanofibrous polymer support is composed of at least one biodegradable polyester comprising at hydroxyacid monomer. 
     
     
         27 . The method of  claim 15 , wherein the nanofibrous polymer support is composed of at least one biodegradable polymer selected from poly((L)-lactic acid), poly(caprolactone) and blends thereof. 
     
     
         28 . The method of  claim 15 , wherein the compression step comprises applying a centrifugal force of between 25 g and 500 g to the polymer-cell matrix for 1 to 10 minutes. 
     
     
         29 . The method of  claim 28 , wherein the compression step further comprises a step of resting the polymer-cell matrix after the compression step. 
     
     
         30 . The method of  claim 28 , wherein the compression step comprises applying the centrifugal force to the cell-polymer scaffold mixture in a vessel, which vessel has a shape corresponding to the desired shape of the tissue engineered cartilage. 
     
     
         31 . The method of  claim 15 , wherein the expanded nanofibrous biocompatible polymer support is formed to form a plurality of larger pores each of which has a diameter of at least 10 microns. 
     
     
         32 . The method of  claim 15 , wherein the bioreactor suspends the cell-polymer aggregate or tissue engineered cartilage in a moving culture medium. 
     
     
         33 . The method of  claim 32 , wherein the bioreactor comprises a culture chamber having a taurus cross-section in to which the cell-polymer matrix and culture medium are placed, and wherein the culture chamber is rotated at a speed sufficient to generate a zero gravity or low gravity mimicking environment in at least a portion of the volume of the culture chamber. 
     
     
         34 . (canceled) 
     
     
         35 . A method of forming cartilage in vivo, the method comprising the steps of providing a nanofibrous polymer support comprising a plurality of polymer nanofibers; and inserting the nanofibrous polymer support into a patient at the position suitable for formation of new cartilage. 
     
     
         36 - 54 . (canceled) 
     
     
         55 . A method of preparing a tissue engineered tissue comprising the steps of
 preparing a nanofibrous biocompatible polymer support;   contacting a suspension of cells with the surface of the support to form a polymer matrix having cells dispersed therein;   culturing the cell-polymer matrix in a bioreactor with a culture medium under conditions conducive cell growth and differentiation to tissue engineered tissue.   
     
     
         56 . A method of preparing a tissue engineered tissue comprising the steps of
 preparing an nanofibrous biocompatible polymer support;   expanding the nanofibrous polymer support thereby increasing interfiber distance;   contacting a suspension of cells with the support to form a polymer matrix having cells dispersed therein;   compressing the cell-polymer matrix to create cell-cell contact and cell-polymer contact;   culturing the compressed cell-polymer matrix in a bioreactor with a culture medium under conditions conducive cell growth and differentiation to tissue engineered tissue.   
     
     
         57 - 73 . (canceled) 
     
     
         74 . A tissue engineered cartilage prepared by the method comprising the steps of:
 preparing a nanofibrous biocompatible polymer support;   contacting a suspension of cells with the surface of the support to form a polymer matrix having cells dispersed therein;   culturing the cell-polymer matrix in a bioreactor with a culture medium under conditions conducive to growth of chondocytes into a tissue engineered cartilage.   
     
     
         75 - 81 . (canceled)