This document discusses biochemical technologies including tissue engineering and nanobiotechnology. It provides information on tissue engineering including its goal of developing biological substitutes to maintain, restore or improve tissue function. Specific tissues that can be engineered are mentioned like skin, cartilage, blood vessels and bone. Components of tissue engineering are discussed including cells, scaffolds, bioreactors and growth factors. Information is also provided on stem cells including their ability to differentiate and regenerate tissues and organs. The main types of stem cells discussed are embryonic and adult stem cells. Adult stem cells sources and uses are elaborated in more detail. Scaffolding materials and functions are defined. Finally, bioreactors and their role in providing controlled conditions for cell growth are summarized.

1. Biochemical Technologies
• Tissue engineering
• Nanobiotechnology

2. Tissue engineering
• “Tissue Engineering is an interdisciplinary
field that applies principles of engineering
and life sciences towards the development
of biological substitutes that aim to
maintain, restore, or improve tissue
function.”
• Tissue Engineering is the in vitro
development (growth) of tissues or organs to
replace or support the function of defective
or injured body parts

3. • Tissue Engineering is the in vitro development
(growth) of tissues or organs to replace or support
the function of defective or injured body parts.
Skin
Cartilage
Blood Vessels
Bone
Muscle
Nerves
Liver
Kidney
Dental
etc. etc.

4. Cellular Communications
Cell-to-Cell Contact:
o some membrane receptors are adhesive molecules
• adherent junctions and desmosomes
o other serve to create junctions between adjacent cells
allowing for direct cytoplasmic communication
• gap junctions
• 1.5-2 nm diameter and only allow transport of small
molecules ~1 kDa

5. Cellular Communications
•Cell-ECM Interactions:
o ECM is multifunctional and also provides a substrate
that cells can communicate
o since cells synthesize the ECM, they can modify the
ECM to elicit specific cellular responses
o several specialized receptors that allow for cell-ECM
interactions
• integrins, CD44, etc.
• also a mechanism by with cells respond to
external stimuli (“mechanical transducers”)

7. Cells
• Cells are taken from the healthy tissue of what tissue is being
created.
o Skin cells for skin, bladder cells for bladder, etc.
• Cells taken from donor or patient themselves
o Autologous-donor and patient are the same
o Allogenic-cells from another person
o Xenogenic-cells from another species
• Separated and screened for pathogens and disease
• Placed onto scaffolds

8. •Stem cells are the bodys "master" cells that regenerate the body many cells,
tissues, and organs. Most cells in your body can only make new cells of the
same type - blood cells make blood cells, skin cells make more skins cells
and so on. Stem cells are unique not only because they can turn into many
different types of cells - a stem cell might create blood, kidney, heart, or bone
for example - but also because they can divide many more times than other
cells.
Stem cells

9. What Are Stem Cells?
Stem cells are the raw
material from which all of
the body’s mature,
differentiated cells are
made. Stem cells give rise
to brain cells, nerve cells,
heart cells, pancreatic
cells, etc.

10. Stem Cell – Definition
 A cell that has the
ability to continuously
divide and
differentiate (develop)
into various other
kind(s) of cells/tissues

11. Components of Tissue
Engineering
• Cells
• Matrix or Scaffold
• Bioreactor
• Cytokines and Growth Factors

12. Stem cells are different from other cells of
the body in that they have the ability to
differentiate into other cell/tissue types. This
ability allows them to replace cells that have
died. With this ability, they have been used
to replace defective cells/tissues in patients
who have certain diseases or defects.
Types of stem cells

13. There are two broad types of stem cells:
embryonic stem cells and adult stem cells.
While there has been much debate on the
ethical issues surrounding the use of
embryonic stem cells, adult stem cells are free
of this controversy and only adult stem cells, to
date, have been used to treat people.
Types of stem cells (conti..)

14. Embryonic stem cells
• “Human embryonic stem (ES) cells are cultured
cell lines derived from the inner cell mass of the
blastocyst that can be grown indefinitely in their
undifferentiated state, yet also are capable of
differentiating into all cells of the adult body.” Two
sources
oFertilized egg from in vitro fertilization
oOvum that has had nucleus removed and nuclear
material injected from intended recipient of final
tissue product (reproductive/therapeutic cloning)
• Very controversial

16. Adult stem cells
• Found in:
o Umbilical cord blood/tissue
o Adult brain, blood cornea, retina, heart, fat,
skin, dental pulp, bone marrow, blood vessels,
skeletal muscle and intestines

17. The most commonly known source of adult
stem cells is bone marrow, which contains both
hematopoietic stem cells (also found in cord
blood)and mesenchymal stem cells (also found
in teeth).

18. Stem Cells
•Stem cells naturally exist in some tissues
(especially those that rapidly proliferate or
remodel) and are present in the circulation.
•There are two predominant lineages of stem
cells:
omesenchymal
• give rise to connective tissues (bone,
cartilage, etc.)
• although found in some tissues, typically
isolated from bone marrow

19. hematopoietic
give rise to blood cells and lymphocytes
isolated from bone marrow, blood
(umbilical cord)
Stem cells are rare; bone marrow typically
has:
a single mesenchymal stem cell for every
1,000,000 myeloid cells
a single hematopoietic stem cell for every
100,000 myeloid cells

20. Stem Cells (Mesenchymal)

21. Stem Cells (Hematopoietic)

22. Scaffolding
• Act as Extra Cellular Matrix for cells
• Function: Delivery of cells to desired sites, define
space for formation, guide development with
appropriate function
• Needs to be able to control the structure and function
of tissue in a predesigned manner.
• Ideally they are biocompatible and biodegradable,
without provoking inflammation or toxicity in the
body.

23. Tissue Engineering Scaffolds
•Biomaterial Scaffolds Materials:
o polymeric
• chitosan, alginate, etc.
• foams, hydrogels, fibres, thin films
o natural
• collagen, elastin, fibrin, etc.
• hydrogels
o ceramic
• calcium phosphate based for bone tissue engineering
• porous structures
o permanent versus resorbable
• degradation typically by hydrolysis
• must match degradation rate with tissue growth
•Chemical and Physical Modifications:
o attachment of growth factors, binding sites for integrins, etc. nanoscale
physical features

24. Bioreactors
• System where conditions are closely controlled to
permit and induce a certain behavior in living cells or
tissues
• Provide controlled and steady flow of cell media
• Factors necessary for cell growth:
o pH, temp. pressure, nutrient supply, waste removal
• Types of Bioreactors
o Spinner Flasks, Rotating Vessels, Hollow Fiber,
Perfusion reactors

25. Culturing of Cells
•Sterilization Methods
o ultra-violet light, 70% ethanol, steam autoclave, gamma
irradiation, ethylene oxide gas
•Growth Conditions
o simulate physiological environment
• pH 7.4, 37°C, 5% CO2, 95% relative humidity
• culture (growth) media replenished periodically
•Culture (Growth) Media
o appropriate chemical environment
• pH, osmolality, ionic strength, buffering agents
o appropriate nutritional environment
• nutrients, amino acids, vitamins, minerals, growth
factors, etc.

26. Tooth anatomy
www.vivianbaedds.com

27. TYPES OF DENTAL STEM CELLS
• Dental Pulp Stem Cells (DPSCs)
• Stem cells from human exfoliated
deciduous teeth (SHEDs)
• Periodontal Ligament (PDLSCs)
• Dental follicle stem cells (DFSCs)
• Apical papilla (SCAPs)
Adapted from http://ww.bioscience.org.

30. INDICATION
1.Dental tissue repair: dental stem cells are currently
considered to offer potential for tissue regeneration

31. Periodontal regeneration: The periodontium is a set of
specialized tissues that surround and support the teeth to
maintain them in the jaw.Periodontitis is an inflammatory
disease that affects the periodontium and results in irreversible
loss of connective tissue attachment and the supporting alveolar
bone.

32. Regeneration of dental pulp inimmature
tooth Dental pulp needs to be removed
when it becomesinfected, and this is
particularly problematic for root pulpthat
requires endodontic (root canal) treatment.

33. Whole tooth regeneration:

34. SummaryTooth Stem Cells Therapeutic PotentialThe ultimate goal of tooth
regeneration is to replacethe lost teeth. Stem cell-based tooth engineering
isdeemed as a promising approach to the making ofa biological tooth (bio-
tooth). Dental pulp stem cells(DPSCs) represent a kind of adult cell colony
whichhas the potent capacity of self-renewing andmultilineage
differentiation. A bio-tooth made fromautogenous DPSCs should be the best
choice forclinical tooth reconstruction.

35. Thank you