MMM, Biomaterials I
MMM (2) , Biomaterials I
MMM (2) , Biomaterials I
13
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Rossella Sala
Rossella Sala
Fichier Détails
| Cartes-fiches | 13 |
|---|---|
| Langue | English |
| Catégorie | Technique |
| Niveau | Université |
| Crée / Actualisé | 09.01.2019 / 09.01.2019 |
| Lien de web |
https://card2brain.ch/box/20190109_mmm_biomaterials_i
|
| Intégrer |
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Biomaterials Definition
- a non-viable material used in a medical device, intended to interact with biological systems
- a substance (other than a drug) or combination of substances, synthetic or natural in origin, used to treat, augment or replace any tissue, organ, or function of the body
Requirements: compatibility
- tissue reactions
- change in properties
- mechanical
- physical
- chemical
- degradation leads to
- local deletorious change
- harmful effects
requirements: mechanical properties
- elasticity
- yield stress
- ductility
- toughness
- creep
- ultimate strength
- hardness
- wear resistance
requirements: manufacturing
- fabrication methods
- quality of raw materials
- superior techniques to obtain excellent surface finish or texture
- capability of material to get safe and efficient sterilization
- cost of product
properties of implant metals
- shiny, opaque, heavy, ductile, thermal and electrically conductive
- closely packed atoms in lattices
- improved strength and corrosion resistance when alloyed
- strength is determined by how easy dislocation propagates
ceramics
- ionically bound atoms
- electrically/thermically insulating, strong, hard, brittle
- corrosion and wear resistant
- alternating charge of ionic structure --> no slip dislocation
polymers
- largest range of properties
- flexible, tough, degradable, biocompatible, inert, transparent
- low friction
- covalent bonds
biomedical polymers, distribution
43% polymers
30% metals
18% compositions
6% naturals
3% ceramics
polyethylene
most widely produced
UHMWPE
ultra high molecular weight polyethylene
- 3 mega Da
- high wear resistance, entanglements of long polymer strands
- non-reactive side groups
- slippery, waxy, water-repellent surface
poly methyl methacrylate
high retractive index, easily processed
environmentally stable, relatively inert
good mechanical properties
polytetrafluoroethylene
do not bind to other molecules than their own
polysiloxanes
elastomers, sealants, coatings --> brest implants, drug delivery
high oxygen permeability
