BME7507_Introduction_Tissue Engineering.ppt

Tissue engineering in biomedical fields

1. BME 7507 Cell & Tissue
Engineering
Maj Md. Maruf Hasan, PhD
Department of Biomedical Engineering
Military Institute of Science and Technology
Mirpur, Dhaka

2. What is Tissue Eng…?
Tissue Engineering (TE) is an interdisciplinary discipline
addressed to create functional three-dimensional (3D)
tissues combining scaffolds, cells and/or bioactive
molecules.
TE involves scientific areas such as cell biology, material
science, chemistry, molecular biology, engineering and
medicine.
TE is the development of biological substitutes that
maintain, improve or restore tissue function.
The term Tissue Engineering (TE) was first presented to
the broad scientific community in 1993 by Langer and
Vacanti.

3. Brief History of Tissue Engg

4. Treatments for damaged tissue
Treatments for damaged tissue include:
Organ transplants
mechanical devices or
surgical reconstruction
Associated problems with above treatments:
Organ transplants show important limitations such as transplant
rejection and lack of donor to cover all the worldwide demand
Mechanical devices are not capable of accomplishing all the
functions associated with the tissue and cannot prevent
progressive patient deterioration
Surgical reconstruction can result in long-term problems

5. Tissue Engineering principles

6. Basic elements of TE
Cells in the body grow within an organized 3D Extra-
Cellular Matrix (ECM), surrounded by other cells. Indeed,
the interactions between cell-cell and cell-ECM can
determine whether a given cell undergoes proliferation,
differentiation, apoptosis or invasion.
TE involves basically three basic elements:
Cells
Scaffolds
Biomolecules: Signaling molecules

7. Cells
Cellsinthebodygrowwithinanorganized3DExtra-
CellularMatrix(ECM),surroundedbyothercells.Indeed,
theinteractionsbetweencell-cellandcell-ECMcan
determinewhetheragivencellundergoesproliferation,
differentiation,apoptosisorinvasion.
Animportantdecisiontomakewhendesigningstrategies
forTEisthecellsourceselection.Thisstepbecomesa
criticalissueespeciallywhenthesestrategiesare
designedtobeclinicallyapplied.Importantly,cellsshould
fulfillabasicrequirement:
Integrate themselves in the specific tissue and
Secret various Growth factors and cytokines that activate
the endogenous tissue regeneration program.

8. Cells from donor tissue-limited supply
Embryonic Stem cells (ESCs) are pluripotent cells that are
able to differentiateinto any lineage but their use is highly
restricted due to ethical controversies
Analternativecelltypeunderstudyfortheirapplicationin
TEareinducedPluripotentStemCells(iPSCs),whichwere
firstgeneratedfrommousefibroblastsandsubsequently
obtainedfromadulthumancells.Basically,iPSCsare
somaticcellsthathavebeenreprogrammedtoa
pluripotentstatethroughtheintroductionofadefinedset
oftranscriptionfactors.Themainadvantagesofthese
cellsaretheirautologouscharacter,theirdifferentiation
capacityandtherobustnessandsimplicityof
reprogrammingprocedure.
Cells

9. Scaffolds
Provides 3D microenvironment for the cells like ECM does
in vivo
Ensures appropriate biophysical, biomechanical and
biochemicalcues that guide cell proliferation,
differentiation, maintenance and function
Requirements of Tissues Engineering Scaffold
Interconnecting pores
Biodegradability
Good surface Chemistry-proliferation, migration,
differentiation
Adequate Mechanical properties
Easier fabrication into varies shapes and sizes.

10. Scaffolds
ScaffoldsforTEcanbedividedinnaturaland
synthetic,dependingonitsorigin.Synthetic Polymers Natural Polymers
Polylacticacid(PLA) Collagen
PolyUrethane(PU) Alginate
Polycaprolactum(PCL) Chitosan
Polylactic Glycolic acid(PLGA)
Hydrogels etc

11. Biomolecules
Playing role in Cell proliferation, Cell differentiation, Cell
communication
Growth factors, chemokines, and cytokines are the
examples of Biomolecules
Signaling molecules used in TE can be added to the
culture media as soluble factors or attached to the
scaffold by covalent and non-covalent interactions.
These biomolecules are rapidly degraded and
deactivated by some cell-secreted enzymes, responsible
for their short biological half-live.
The controlled release of different factors from
scaffolds allows their constant renewal, having a great
potential to direct tissue regeneration and formation.

12. Application of TE
Bone tissue engineering
Cartilage tissue engineering
Cardiac tissue engineering
Neural tissue engineering
Liver tissue engineering
Pancreas tissue engineering
Vascular tissue engineering
Modeling Human Physiology
Drug discovery

13. Technologies used in TE