Tissue engineering

tissue engineering, cells, human bodies,animals and plants

1. Tissue engineering Unit-2

2. SYNOPSIS Introduction Process involved Stem cells Scaffolds Materials used Methods for synthesis of TE scaffolds Applications Advantage of TE Disadvantage of TE

3. INTRODUCTION 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 functions. The term has also been applied to efforts to perform specific biochemical functions using cells within an artificially-created support system (e.g. an artificial pancreas, or a bio artificial liver).

4. examples Bio artificial windpipe Bio artificial liver device Artificial pancreas Cartilage Doris Taylor ‘s heart in a jar Tissue engineered airway Tissue engineered vessels Artificial skin Artificial bone marrow Artificial bone Oral mucosa tissue engineering Foreskin

5. PROCESS OF TISSUE ENGINEERING Start building material (e.g., extracellular matrix, biodegradable polymer). Shape it as needed. Seed it with living cells . Bathe it with growth factors. Cells multiply & fill up the scaffold & grow into three-dimensional tissue. Implanted in the body. Cells recreate their intended tissue functions. Blood vessels attach themselves to the new tissue. The scaffold dissolves. The newly grown tissue eventually blends in with its surroundings.

6. Process involving tissue engineering

7. EXTRACTION OF CELLS From fluid tissues such as blood, cells are extracted by bulk methods, usually centrifugation or apheresis . From solid tissues, extraction is more difficult. Usually the tissue is minced, and then digested with the enzymes trypsin or collagenase to remove the extracellular matrix ( ECM) that holds the cells. After that, the cells are free floating, and extracted using centrifugation or apheresis.

8. APHERESIS PROCESS

9. Stem cells cells Stem cells are undifferentiated cells with the ability to divide in culture and give rise to different forms of specialized cells. According to their source stem cells are divided multipotent pluripotent totipotent unipotent

10. Stem cell types

11. SCAFFOLDS Cells are often implanted or 'seeded' into an artificial structure capable of supporting three-dimensional tissue formation. These structures , typically called scaffolds Scaffolds usually serve at least one of the following purposes: Allow cell attachment and migration Deliver and retain cells and biochemical factors Enable diffusion of vital cell nutrients and expressed products Exert certain mechanical and biological influences to modify the behavior of the cell phase

12. MATERIALS USED Many different materials (natural and synthetic, biodegradable and permanent) have been investigated. Examples of the materials are collagen and some polyesters . New biomaterials have been engineered to have ideal properties and functional customization: injectability , synthetic manufacture , biocompatibility, non-immunogenicity, transparency, nano -scale fibers, low concentration, resorption rates, etc.

13. Proteic materials, such as collagen or fibrin, and polysaccharidic materials, like chitosan or glycosaminoglycans (GAGs), have all proved suitable in terms of cell compatibility, but some issues with potential immunogenicity still remains.

14. METHODS FOR SYNTHESIS OF TISSUE ENGINEERED SCAFFOLDS Nano fiber Self-Assembly Textile technologies Solvent Casting & Particulate Leaching (SCPL) Gas Foaming Emulsification/Freeze-drying Thermally Induced Phase Separation (TIPS) CAD/CAM Technologies Laser-assisted Bio Printing ( LaBP )

15. APPLICATION Tissue engineering covers a broad range of applications, in practice the term has come to represent applications that repair or replace structural tissues (i.e., bone, cartilage, blood vessels, bladder, etc ). A closely related (and older) field is cell transplantation. This field is concerned with the transplantation of cells that perform a specific biochemical function (e.g., an artificial pancreas , or an artificial liver ). Tissue engineering solves problems by using living cells as engineering materials.

16. Tissue engineered heart valves offer a promising alternative for the replacement of diseased heart valves avoiding the limitations faced with currently available bio prosthetic and mechanical heart valves . Tissue-engineered skin is a significant advance in the field of wound healing and was developed due to limitations associated with the use of autografts .

17. ADVANTAGE OF TISSUE ENGINEERING

18. DISADVANTAGE OF TISSUE ENGINEERING

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