Published on: Mar 3, 2016
Transcripts - natural polymer
A polyamide is a macromolecule with repeating
units linked by amide bonds
Polyamides occur both naturally and artificially
Examples of naturally polyamides are proteins, such as
wool and silk
Artificially polyamides can be made through step-
growth polymerization or solid-phase synthesis ,such as
History of Polyamides
Polyamides have existed in nature
(proteins) longer then humans have
existed on earth. However the first
signs of polyamides synthetically
were in 1664 when a Chinese
emperor developed a project to
manufacture synthetic yarn. Many
types of polyamides were
discovered at different times in
history but they were not recognized
as such until later on. Polyamide 6
for example was discovered in 1936
by Paul Slack and sold as Perlon
but nylon was truly discovered in
1933 by Dr. Wallace Hume
Carothers (as polyamide 6.6).
FORMING A POLYAMIDE
Tensile strength is 160-210(MPa)
Density : 1.14gm/c.c
Elongation at break : 15-45%
Melting point : 215oC
Ability to protest friction : Excellent
Ability to protest heat : up to 150oC
Acids: it has not enough ability against acidic
Basic. Basic does not cause harm
have enough ability against alkali.
Effect of bleaching Strong oxidizing agent is
Biocompatibility test results met the acceptance criteria
for ISO 10993.
Cytotoxicity testing showed that the material is nontoxic
“Tests for Local Effects after Implantation:” Both a two-
week and 12-week duration test was performed to assess
the in vitro cytotoxicity of medical devices
Used as sutures
Cable insulation for medical devices
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Collagen is a family of highly developed fibrous
proteins found in all multicellular animals. It is the most
abundant proteins found in mammals, it is 25 percent of
the total protein mass.
Collagen is the main fibrous component of skin, bone,
tendon, cartilage .
Collagen is a natural protein that provides our bodies
with structural support
STRUCTURE OF COLLAGEN
All collagens are composed of 3 polypeptide alpha chains coiled
around each other to form the tripe helix configuration. The
individual polypeptide chains of collagen each contain approx 1000
amino acid residues .
Here is the molecular formula:C2H5NOC5H9NOC5H10NO2.
This is also the structural formula of Collagen
FORMATION OF COLLAGEN
Collagen contains specific amino acids – Glycine,
Proline, Hydroxyproline and Arginine. These amino
acids have a regular arrangement in each of the three
chains of these collagen subunits.
The sequence often follows the pattern Gly-Pro-X or
where X may be any of various other amino acid
It’s boiling point is between 150-190°C depending on the type
Its relative molecular mass is 255
It has a glass transition temperature of 135 °C and a
degradation temperature of 433 °C
It’s solubility depends on the type, but generally it isn’t very
Collagen is a fibre, or when fully grown, a mesh of fibres
Rich in amino acids-Glysine, proline, hydroxylysine and
TYPES OF COLLAGEN
The collagen family consists of 28 members and these are classified
Variations are due to …..
1. Differences in the assembly of basic polypeptide chains
2. Different lengths of the helix
3. Various interruptions in the helix and
4. Differences in the terminations of the helical domains
I Provides tensile strength to connective tissue
II Provides tensile strength to connective tissue
III Forms structural framework of spleen, liver, smooth
muscle, adipose tissue. Provides tensile strength to
IV Forms meshwork of the lamina densa of the basal
lamina to provide support and filtration
V Provides tensile strength, associated with type I
collagen, also with placental ground substance.
VI Bridging between cells and matrix
VII Forms anchoring fibrils that fasten lamina
densa to underlying lamina reticularis
VIII Tissue support, porous meshwork, provide
IX Associates with type II collagen fibers
X Calcium binding
XI Provides tensile strength, controlling lateral growth
of type II
XII Associated with type I collagen fibers
XIII Cell matrix
XIV Modulates fibril interactions
XV Proteolytic release of antiangiogenic factor
XVII Cell to matrix attachment
XVIII Proteolytic release of antiangiogenic factor
XIX formation of hippocampal synapses
XXIV Regulation of type I fibrillogenesis, marker
of osteoblast differentiation and bone
XXVII cartilage calciﬁcation, Association with
type II fibrils (?)
Collagen is regarded as one of the most useful biomaterials.
The excellent biocompatibility and safety due to its biological
characteristics, such as
◦ weak antigenicity.
To repair tissues such as bone, tendon, ligament, skin,
vascular and connective tissues.
Drug delivery applications: to develop scaffolds for delivery
of genes, cell, growth factors, anesthetics, antibiotics etc.
Tissue augmentation: For use in plastic surgery
To enhance blood coagulation and platelet activation
To enhance durability of allograft tissues.
In guided tissue regeneration.
Can be used for the generation of bone substitutes,
wound dressings, nerve regeneration.
For use as a research tool to study diseases such as diabetes,
Biodegradable and bio-reabsorbable.
Non-toxic and biocompatible.
Biological plastic due to high tensile strength and minimal
Hemostatic — promotes blood coagulation.
Formulated in a number of different forms.
Biodegradability can be regulated by cross-linking.
Easily modiﬁable to produce materials as desired by utilizing its
Compatible with synthetic polymers.
High cost of pure type I collagen.
Variability of isolated collagen.
Hydrophilicity which leads to swelling.
Complex handling properties.