1. Biomaterials
A biomaterial is any material, that comprises
whole or part of a living structure or a
biomedical device which performs, increase,
or replaces a function that has been lost
through disease or injury.
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2. Application
of Biomaterials
Tissue Engineering
• Study of the growth of new
connective tissues, or organs,
from cells and a scaffold to
produce a fully functional organ
for implantation back into the
donor host or by injecting /
applying hydrogel.
• Hydrogel=Self Healing Biomaterial
Drug Delivery
• Refers to approaches, formulations,
technologies, and systems for
transporting a pharmaceutical
compound in the body as needed
to safely achieve its desired
therapeutic effect. It is typically
concerned with both quantity and
duration of drug presence.
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3. Tissue Engineering
• Involve development of biological substitutes that
restore, maintain, or improve function of tissue
or whole organ.
• Involving the combining of cells, scaffold, and
bioactive agents to fabricate functional new
tissue to replace damaged tissue.
• Cells are often seeded in or onto biomaterials
prior to transplantation.
• These materials serve as temporary scaffolds and
promote cell reorganization to a functional
tissue.
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4. Basic principle of Tissue
engineering:
Cells can be isolated (a) from the
patient’s body, and expanded in
a petridish in laboratory (b).
Once we have enough number of
cells, they can be seeded on a
scaffold (c), and cultured in vitro
in a bioreactor or incubator (d).
When the construct is matured
enough, then it can be implanted
in the area of defect in patient’s
body (e).
Stem cells are biological cells found in all multicellular organisms, that can divide
(through mitosis) and differentiate into diverse specialized cell types and can self-
renew to produce more stem cells.
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5. Scaffold
• An artificial structure capable of supporting three-
dimensional tissue formation.
• Scaffold can be fabricated in the shape of the tissue
we want to restore.
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6. Scaffold
• Examples of biomaterial used as scaffolds;
1. Collagen
2. Gelatin
3. Polyglycolic Acid (PGA)
4. Poly (L-Lactic Acid) (PLLA)
5. Poly (DL-Lactic-Co-Glycolic Acid) (PLGA)
6. Hydrogel (Smart Biomaterial)
• Scaffold can be fabricated via various techiques;
1. 3-D Printing
2. Gas Foaming
3. Solvent Based Techniques
4. Electrospinning
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8. Scaffold
To achieve the goal of tissue reconstruction, scaffolds must meet
some specific requirements.
A high porosity and an adequate pore size are necessary to facilitate
cell seeding and diffusion throughout the whole structure of both
cells and nutrients.
Biodegradability is often an essential factor since scaffolds should
preferably be absorbed by the surrounding tissues without the
necessity of a surgical removal.
The rate at which degradation occurs has to coincide as much as
possible with the rate of tissue formation: this means that while
cells are fabricating their own natural matrix structure around
themselves, the scaffold is able to provide structural integrity within
the body and eventually it will break down leaving the neotissue,
newly formed tissue which will take over the mechanical load.
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9. Scaffold
Characteristics of scaffolds:
1) Biocompatibility
Cells must adhere, function normally, and migrate onto
the surface and eventually through the scaffold and
begin to proliferate before laying down new matrix.
After implantation, the scaffold or tissue engineered
construct must elicit a negligible immune reaction in
order to prevent it causing such a severe inflammatory
response that it might reduce healing or cause rejection
by the body.
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10. Scaffold
Characteristics of scaffolds:
2) Biodegradability
• Scaffolds are not intended as permanent implants. The
scaffold must therefore be biodegradable so as to allow
cells to produce their own extracellular matrix.
• The by-products of this degradation should also be non-
toxic and able to exit the body without interference with
other organs.
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11. Scaffold
Characteristics of scaffolds:
3) Mechanical properties
Able to maintain the structure and function immediately after
implantation and during remodeling of the implants .
4) Scaffold architecture
Have an interconnected pore structure and high porosity to ensure
cellular penetration and adequate diffusion of nutrients to cells
within the construct and to the extra-cellular matrix formed by
these cells.
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12. Application : Scaffolds for Bone Tissue
Natural bone matrix is a composite of
biological ceramic (apatite) and biological
polymer.
Carbonated hydroxyapatite Ca10(PO4)6(OH)2
accounts for nearly two-thirds of the bone
weight. The inorganic component provides
compressive strength to the bone.
Roughly one-third of the weight is from
collagen fibers. Collagen fibers are tough
and flexible , thus tolerate stretching,
twisting and bending.
For these reasons polymers, ceramics or
their composites have been chosen as
scaffold for bone repair. They can be
synthetic or naturally occurring ones.
Hydroxyapatite:
A calcium phosphate mineral.
Calcium phosphate is the name given to a family of minerals containing calcium ions (Ca2+) together
with ortho-phosphates (PO4
3-), meta-phosphates (PO3
−) or pyrophosphates (P2O7
4-) 12
15. Mechanism
• Cross-linking of polymer strains
are essential in the self-healing
propery of second generation
biomaterial
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16. Hydrogel
(Self Healing Biomaterial)
• Water swollen polymeric structures
cross-linked together.
– Cross-links produced through:
• Chemical reaction to form covalent
bonds
• Entanglement of polymers
• Hydrogen bonding and van der Walls
forces
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19. Hydrogel response to environmental
stimuli
• Hydrogels as 3D cross-linked
hydrophilic polymer networks are
capable of swelling or de-swelling
reversibly in water and retaining
large volume of liquid in swollen
state. Hydrogels can be designed
with controllable responses as to
shrink or expand with changes in
external environmental conditions.
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20. Important Properties
• Swelling
– Solute diffusion
– Surface properties and mobility
– Optical properties
– Mechanical properties
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21. Important Properties
• pH sensitive hydrogels
– pH responsive hydrogels contain acidic or basic
pendent groups
– In appropriate media these groups ionize forming
charges on the gel
• Increases swelling forces due to localization of charges
on the pendent group
• Mesh size can change significantly with little change in
pH
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22. Important Properties
• Temperature sensitive hydrogels
– Exhibit lower critical solution temperatures (LCST),
temperature at which at which a polymer is
soluble
• Above this temperature the hydrogel is hydrophobic
and does not significantly swell in water.
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25. Uses of Hydrogel
• Biomaterial, coatings for medical devices,
contact lenses
– Biologically compatible
• Drug delivery
– Degradable, swelling properties
• Many other biological applications
– Develop human tissues
• Food
– Jell-o
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26. • Schematic illustration of the most common
tissue engineering approaches.
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Applications
Hydrogel – based scaffold :
Ability to tailor their
mechanical characteristics
to mimic those of natural
tissues.
28. Drug Delivery for Healing Wounds
• A dry hydrogel contains a water soluble drug
• Anti-Fibrinolytic drugs (Aprotinin , Epsilon ‐
Aminocaproic Acid and Aminomethylbenzoic Acid )
promote blood clotting by preventing blood clots from
breaking down.
• Drug is immobile in the hydrogel matrix and begins to
diffuse out when the hydrogel begins to swell with
water.
• Stop blood loss in seriously injured patients and, as a
result, save lives.
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29. Hydrogel Scaffold With Self-Forming Fibers
Highly Effective for Burn Wounds
• Nanogel, that’s excellent at promoting the
healing of second and third degree burns.
• The material is made out of peptide
hydrogels that works like a scaffold within
which cells can grow.
• When water is added to this scaffold, the
peptides naturally group together into fibers,
trapping the water inside. This allows the
material to be both porous, while retaining
moisture that helps promote cellular growth.
• The researchers compared the material
against commonly used silicone dressings
and found it to be significantly more
effective at wound healing. There haven’t
been human studies done yet, but the
findings are certainly promising.
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30. method or process of administering a
pharmaceutical compound to achieve a
therapeutic effect in humans or animals
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32. Methods :
1) Controllable released method
• delivery of compounds (e.g., drugs, proteins, fertilizers, nutrients, and other
biologically active agents) at an effective level in response to time and stimuli (e.g.,
pH, temperature, enzymes, UV light, magnetic fields, osmosis)
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33. Fig. 1 Drug levels in the plasma released from traditional release system,
a combination of multiple oral capsules or injection dosing (blue dashed
curve), and controlled release system (red continuous curve)
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37. Advantages
• improved patient compliance due to less frequent
drug administration
• reduction of fluctuation in steady-state drug levels
• maximum utilization of the drug
• increased safety margin of potent drug,
• reduction in healthcare costs through improved
therapy
• shorter treatment period.
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38. 3) Pulsatile-Release Formulation
• Release of finite amount of drug at distinct time intervals
that are programmed into the drug product
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42. 4) Delayed-Release Formulation
• delay release of the medication until the tablet has
passed through the stomach to prevent the drug
from being destroyed or inactivated by gastric juices
or where it may irritate the gastric mucosa
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