Natural Materials Study Guide Flashcards
State two advantages of using a natural polymer versus a synthetic polymer for biodegradable polymer applications?
– similar or identical to host tissue, able to deal with the biological environment
– non-toxic and low inflammatory reaction
– ability to be degraded by natural enzymes, ideal for shortterm applications – degradation byproducts disposed metabolically
– controlled degradation rate by crosslinking and modifications
give example of two natural polymer for biomedical applications
collagen-used in bone tissue engieering. used in the coating of bioactive cermaics
hyaluronic acid gells used in opthalmology. facilitate cataract surgery and retinal rettachment
GAG used for inducing regeneration fo skin
___ is an example of a protein base natural polymer.
silk keratin collagen gelatin fibrinogen elastin actin myosin
what is a GAG as it relates to the defination of a natural polymer
glycosaminoglycan
heteropolysaccharides which contain an N-acetylated hexosamine (a 6-carbon sugar with an added amino group, lobster shell) in a characteristic repeating disaccharide unit
name two characteristics of elastin
highly amorphous
exhibits ideal rubber elasticity
insouble elastin can be degraded by the enzyme elatase
___, _____ and ____ amino acids are major components of collagen type I proteins
glycine, proline, hydroxyproline
state two biomedical applications of heparin.
anti-coagulant for blood
prevention and treatment of deep vein thrombosois
adjunctive therapy in the treatment of arterial thrombosis
what are the most abundant polysaccarides in the human body?
glycosaminoglycan (GAG)
what is a glycoprotein?
proteins containing one or more covalently linked carbohydrates residues
describe the four levels of structural organization of collagen.
- primary structure-sequence of amino acids
- secondary structure- local configuration of polypeptides chains that results from satisfaction of sterochemical angles and hydrogen bonding between peptide residues
- teriary-global configurations of polypeptide chains…triple helical collagen molecule
- quaternary- denotes repeating supramolecular unit structure-comprising several molecules packed into a specific lattice. basic unit of the microfil
give an example of chemical modification of collagen
chemical cross-linking is used to decelerate the degration rate
treatment with specific reagents to reduce the immunogenicity of collagen by extracting portions eliciting production of antibodies
give an example of physical modification of collagen
-the tertiary structure (triple helix) can be disrupted by heating
–the quaternary (i.e. fibrillar) organization can be disrupted by adjusting pH
–Introducing porosity • pore channels are ports of entry for:
– cells migrating from adjacent tissues into the bulk of the implant
elaborate with example and applications of two forms of collagen
microspheres
• Cells are encapsulated in small collagen spheres. • The spheres are formed by emulsifying collagen and liquid paraffin oil. • Cells, hormones, and growth factors can then be seeded into the microspheres.
conduits
• Collagen conduits are tools to help restore neurological damage. • Collagen conduits are generally multichambered, and are made from allowing collagen to self assemble on a negative mold. • They are biodegradable, flexible, and have less tendency to cause a negative host response
electrospun fibres
• Uses an electrical field to control the deposition of collagen fibers onto a substrate. • The fiber is spun from an aqueous solution fed through a thin needle. • It produces one long, continuous collagen fiber. • The scaffolds are quick and inexpensive to produce.
what is a monosaccaride
simple sugar; carbohydrate which cannot be decomposed by hydrolysis
list three disadvantages of using natural polymers versus synthetic polymers
immunogenicity they are more likely to desplay sites triggering a immunological reaction
temperature sensitivity
alot more variability
inadequate biomechanical properties
