Tissue engineering

Educational content about tissue enginering

1. Tissue Engineering P.Samuel, Ph.D Assistant Professor of Biotechnology, ANJA College, Sivakasi

2. What is Tissue engineering? Tissue engineering  is the use of a combination of  cells ,  engineering  and  materials  methods, and suitable  biochemical  and physicochemical factors to improve or replace  biological  tissues . The term  regenerative medicine  is often used synonymously with tissue engineering, although those involved in  regenerative medicine  place more emphasis on the use of  stem cells  or  progenitor cells  to produce tissues . Langer and Vacanti were the first to state the definition for tissue engineering.

3. Steps in regenerative medicine

4. According to Langer and Vacanti, tissue engineering can be defined as this is an interdisciplinary field based on the principles of engineering and life sciences to produce biological substitutes to restore the function of damaged organ. Scientific advances in  biomaterials , stem cells,  growth  and differentiation factors, and  biomimetic  environments have created unique opportunities to fabricate tissues in the laboratory from combinations of engineered extracellular matrices ("scaffolds"), cells, and biologically active molecules.

5. Cells are the building blocks Tissue engineering uses living cells as engineering materials. Ex: living  fibroblasts  in  skin  replacement or repair and cartilage repaired with living  chondrocytes . While scientist were involved in a project on extending telomeres (1998) discovered immortalized cell lines.

6. Extraction of Cells Blood is the source of cells usually  centrifugation  or  apheresis . In the case when cells are extracted From solid tissues tissue is minced, and then digested with the  enzymes   trypsin  or  collagenase  to remove the  extracellular matrix After that, the cells are free floating, and extracted using centrifugation or  apheresis

7. Types of cells Autologous cells: Cells are harvested from the individual itself. Under some circumstances like genetic diseases and burns the cells are not available. Recently there has been a trend towards the use of  mesenchymal stem cells  from  bone marrow  and  fat . These cells can differentiate into a variety of tissue types, including  bone ,  cartilage ,  fat , and  nerve .

8. Allogeneic  cells come from the body of a donor of the same species.  Xenogenic  cells are these isolated from individuals of another species particularly animal cells are use for construction of cardio vascular implants. Syngenic  or  isogenic  cells are isolated from genetically identical organisms, such as twins, clones, or highly inbred research animal models . Primary  cells are from an organism . Secondary  cells are from a cell bank.

9. Scaffold Scaffold is a support that allow the seeded cells to interact and establish in to a new organ. It functions like ECM . The scaffold material should be Biocompatible and Biodegradable. Materials: Collagen, Polyester, Polyglycolic acid and Polycaprolactone . Carbon nanotubes as scaffolds

10. Synthesis of scaffold Nanofibre self assembly Textile technologies Solvent casting and particulate leaching Gas foaming Emulsification – freeze drying Thermally induced phase separation Electrospinning

11. Bioreactor for tissue engineering The  Bioreactors  used for 3D cell cultures are small plastic cylindrical chambers. The bioreactor uses  bioactive  synthetic materials such as  polyethylene terephthalate  membranes to surround the spheroid cells.  They are easy to open and close, so that cell spheroids can be removed for testing, yet the chamber is able to maintain 100% humidity throughout . MC2 Biotek  has developed a bioreactor known as ProtoTissue ]  that uses  gas exchange  to maintain high oxygen levels

12. Applications of Tissue engineering