This document provides an overview of tissue engineering. It discusses the process of tissue engineering which involves using a scaffold material, seeding it with living cells, using growth factors, and implanting the new tissue. It also describes different types of stem cells, materials used for scaffolds, and methods to synthesize tissue engineered scaffolds. Applications of tissue engineering include bioartificial organs and tissues like skin, bone, and blood vessels. Both advantages and disadvantages of the field are mentioned.

1. Unit-2

2. SYNOPSIS
 Introduction
 Process involved
 Stem cells
 Scaffolds
 Materials used
 Methods for synthesis ofTE 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
 DorisTaylor ‘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

13. 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.

14.  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.

15. 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/CAMTechnologies
 Laser-assisted Bio Printing (LaBP)

16. 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.

17.  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.

18. ADVANTAGE OF TISSUE
ENGINEERING

19. DISADVANTAGE OF TISSUE
ENGINEERING