CHAPTER 7 Tissue Engineering 7.1 P aradigms /Strategies 7.2 Ce lls 7.3 Matrices 7.4 Regulators 7.1 ELEMENTS OF TISSUE E NGINEERING MATRICES (porous structures) Synthetic Polymers (absorbable) Polyactic acid Polyglycolic acid Natural Polymers (absorbable) Collagen (Types I, II, III, IV) Collagen - GAG copolymer Fibrin Chitosan Synthetic Poly mer (nonresorbable) PTFE Synthetic Ceramics Calcium Phosphate Natural Mineral Bone Mineral CELLS Autologous Allogenic Marrow Stromal Stem Cell Phenotypically Altered Cells Genetically Altered Cells SOLUBLE REGULATOPRS Growth Factors (polypeptide mitogens) Differentiation Factors (e.g., BMP) ---- ---- ---- ---- ---- ---- ---- 7.1 STRATEGIES FOR TISSUE ENGINEERING TISSUE MATRICES (Resorbable) REGULATORS EXOGENOUS CELLS CONNECTIVE TISSUE Dermis Collagen- GAG (C- G) Polyactic Acid (PLA) Polyglycolic Acid (PGA) PDGF FGF TGF- b Fibroblasts BONE Synthe tc Hydroxyapatite (HA) Tricalcium Phosphate Natural Bone Mineral (Anorgani c Bovine Bone) PLA Collagen Collagen- HA/TCP BMP Marrow Stromal Stem Cells Articular Cartilage C - G Collagen PGA BMP Autologous Articular Chondrocytes Allogene ic Articular Chondrocytes Ligament Collagen Fibers PLA Fibers FGF Fibroblasts Tendon Collagen Fibers PLA Fibers C - G Meniscus C - G EPITHELIA Epidermis C - G PGA EGF Epidermal cells (Keratinocytes) NERVE Peripheral Endothelial Sillicone Tube Collagen Tube C - G PGA Endothelial Cells * PDFG- platelet derived growth factor; FGF- fibroblast growth factor; TGF- b- transforming growth factor; EGF- epidermal growth factor; BMP- bone morphogene tic protein