Lecture 2 Flashcards
(21 cards)
What is a major component of the provisionion matrix which is also involved in angiogenesis?
Fibrin
What happens when the complement system is activated?
A series of protein cascade reactions which lead to:
attacking of bacterial membranes
opsonisation of antigens
attraction of immune cells
What happens in stage 7 of implantation (FBR)?
macrophages fuse to form FBGC
interaction between macrophages, fibroblasts etc
In what situations would the fibrotic capsule not form?
Bioactive materials or surfaces
Biodegradable materials
toxic materials
Rules of protein adsorption
soft proteins adsorb more readily
competitive and reversible
surface property influences it
roughness and pH influence too
What inflammation mediators are triggered at the onset of damaging vascularised connective tissue?
Amylase
What happens at stage 8 of implantation (fibrous capsule development)
lay down collagen type I
walls off biomaterial
bioinert or porous = thinner cpasule
Are macrophages able to release growth factors?
Yes
What is the benefit of understanding the FBR?
Safety + function + short term/long term integrity
What is the vroman effect?
Protein displacement or no displacement
higher concentration/mobility = higher init adsorption
higher affinity = higher equilibrium adsorption
What is the timeframe for forming a protein layer on surface?
seconds
What are integrins?
Help cells attach based on the molecules
What happens in stage 1 of implantation (injury/implantation)?
inflammatory fluid
innate immune response
histamines etc.
What happens in stage 3 of implantation (provisional matrix formation)?
minutes to hours
mix of cells to form structure (platelets, cytokines, cells etc.)
What is the timeframe for an equilibrium protein layer to form?
minutes
Describe apatite formation on surface treated titanium alloys
ion exchange with surface and ions
What happens in stage 6 of implantation (granular tissue formation)?
fibroblasts lay down collagen type III
scar tissue formation (looks dotty)
Can macrophages release histamines?
No
What happens in stage 4 of implantation (acute inflammation)?
a week or so
neutrophils!!
kill microbes and engulf particles
involves antimicrobial agents, mast cells, interleukins
What happens in stage 2 of implantation (blood-biomaterial interaction)?
monolayer of proteins form on the biomaterial (seconds)
equilibrium = minutes)
depends on material properties
What happens in stage 5 of implantation (chronic inflammation)?
longer term
macrophages!
release cytokines and growth factors
fuse into FBGC
