Karteikarten
Biomaterials - Introduction (wk. 1)
Karten in diesem Stapel (48)
- 1FingerjointSilicone rubber
- 2Breast ImplantSilicones
- 3Heart ValvePolyester
Stainless Steel - 4Hip JointTitanium
- 5Artificial HeartPolyurethane
Metal - 6Intraocular Lens (IOL)Poly(methyl methacrylate)
- 7Applications of Biomaterials: Sutures Name 5 advantagesAMAGE (town in France)
- Any tissue
- Minimal tissue reaction
- Absorbable
- Good knot security
- Easy to handle - 8Intraocular Lens - name a) materials b) 3 propertiesa) Poly(methyl methacrylate) PMMA
b)
1) high refractive index (n)
2) easily processed
3) environmentally stable (relatively inert) - 9Name as many medical device examples as you can. There are 12 on the slidesSutures, Catheters, Blood Bags
Contact Lenses, IOL,
Knee & Hip, Breast Prostheses
Dental implants, Renal dialyzers
Oxygenators, CPB
(cardiopulmonary bypass system)
Vascular grafts, pacemakers - 10Which are Biomaterials? why? a) contact lens b) splinter c) vascular graft d) clutchesa) & c)
A biomaterial must interface with the biological system directly. When used, nothing between the device and person using it.
The splinter and clutches can be held through gloves or other things. - 11Biomaterialmaterial interface w biological system to treat/evaluate/augment/replace tissues/organs/bodily functions
- 12Biomaterials Sciencestudy of biomaterials and their interactions with biological environment, includes
1) Materials Science
2) Biological topics: immunology, toxicology, wound healing process - 13biocompatibilityability of a material to perform w an apropriate host response in a specific application
- 14Reasoning BiocompatibilityProtein & cellular response to material which determines overall success of the implant.
Arises from differences between living and non-living materials - 15Biocompatibility responses: 1) temporal 2) othertemporal response: redness, swelling, warmth, pain around implant
other: activation of immune system, localized blood clotting, infection, tumor formation - 16Bioimplants trigger....Inflammation
&
Foreign body response(FBR) - 17biocompatibility testingin vitro: lab environment
in vivo: biomaterial implantation in a living system (animal, rat) - 18biocompatibility testing agenciesASTM International
International Organisation for Standardization (ISO) - 19biocompatibility testing stepsNot all products all steps
1) in vitro
2) in vivo healthy
3) in vivo sick (inject disease, then drug)
4) controlled clinical trials - 20New testing required for a) new devices b) new materials c) both new devices and materialsa) new devices
FDA approves Devices not Materials. - 21amount of testing depends onperceived danger
intended use (device class) - 22Types of biomaterials
- 23Cobalt-chromium alloys: Co-Cr Applications (3)artificial heart valves
dental prostheses
artificial joint components - 24Au, Pt Gold & PlatinumDental fillings,
electrodes for cochlear implants - 25Silver-tin-copper alloys Ag-Sn-Cudental amalgrams
- 26Stainless steeldental prosthesis
vascular stents - 27Titanium alloysartificial heart valve
artificial joint components
pacemaker cases - 28Ceramics: aluminum oxide Al2O3Orthopedic joint replacement components
- 29Ceramics: Bioactive glassesBone graft substitute materials,
dental implants - 30Ceramics: Calcium Phosphatesbone graft substitute materials, dental implants, bone cements
- 31Natural PolymersCan be derived from sources w/in body (collagen, fibrin) or outside the body (chitosan [from seafood shells], alginate)
Collagen: Collagen type I & II
Fibrin: protein-based, blood clotting factors
= fibrinogen + thrombin
chitosan = chitin derived
from the shells of crabs, shrimps - 32Collagenlong, fibrous, extremely strong protein
inside connective tissue. keeps skin elastic - 33Fibrinrepairs cartilage defects, other orthopedic applications
- 34Chitosancommonly sold as tablet "fat attracter" - attract fat and expel from body for weight loss.
- 35Synthetic polymersElastomers:
-highly elastic, w/stand large deformation at low stress and rebound.
- good for cardiovascular applications, wherever tissue elasticity is requried
- EXAMPLE: polydimethylsiloxane (PDMS)
Hydrogels:
-swell in water, retain water in structure
- suitable for soft tissue applications
- polyethylene glycol (PEG) - 36Natural vs. Synthetic Polymers
- 37Which class(es) of biomaterials for an artificial tendon? why? [hint: a tissue that must sustain substantial deformation at low forces and return rapidly to its original dimensions upon release of stress] a) metals b) ceramics c) polymersC) Polymers
especially elastomers because of elasticity (ability to withstand large deformations at low stress and rebound) - 38Important properties of biomaterials: The selection of biomaterials for a given application is determined by: (3)1) degradative
2) surface properties
3) bulk properties - 39Biodegradableability to break down safely, reliable, and relatively quickly
can be undesired/desired, time before failure
important to check biocompatibility during degradation too - 40Medical Applications of Biodegradable Poolymers
- 41What are the 4 layers of a biomaterial interfacing with a biological system?
- 42Importance: Surface properties- a few atomic layers of the exterior
- determines biological response
- determines protein absorption
- surface properties can be different from the bulk properties (due to surface modification/special surface processing) - 43chemical vs physical characteristics (surface property)chemical: hydophobicity/hydrophilicity
physical: surface roughness (increases cell adhesion) - 44Would a hydrophobic or hydrophilic polymer be more appropriate for a contact lens application? Why? Would a melting temperature of the polymer above or below 37 degrees be better? why?Hydrophilic - eye is a watery environment
above - you don't want it to melt - 45importance: Bulk propertiessmaller role than surface characteristics
but have a long term impact - 46mechanical, physical, chemical properties (bulk property)mechanical properties:
- strength, stiffness
-anisotropy: different mechanical properties in different directions
fatigue
physical: crystallinity, thermal transitions
chemical: hdyrophobicity - 47spectroscopymeasures how compounds absorb different types of energy
- 48chromatographyphysically separates molecules based on chemical characteristics (i.e., charge or size)
Informationen
- Beschreibung
- BME32105 Lecture 1 Credit to Professor Mo Yang at the Hong Kong Polytechnic University
- Erstellt von
- Christine Luk
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- 164
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