Biocompatibility: Material Responses in a Biological Environment Flashcards
a biomaterial’s biocompatibility
the biological performance in an intended application that is judged suitable to the specific situation
material response
the material behaviour when placed in the microenvironment of living systems
host response
the local and systemic response of living systems as a result of the material
what contributes to biocompatibility assessment
host response
testing of these properties using relevant assays
material response
biocompatible
what does biocompatibility mean in the clinic
materials go through testing and approval to ensure it is safe and effective
what factors contribute to biocompatibility
host responses to biomaterials
material responses in a biological environment
overall biomaterial response
swelling
the movement of atomic or molecular species from the body fluids into a plastic
the motion of water/lipids into a polymer
leaching
the movement of a material component from the plastic into the body
solute or solvent leaving a polymer into biological fluid
driving force
why a change happens
concentration gradient
mechanism
how the change occurs
pathway to move through water
what defines the likelihood and method of a material change
the combination of driving force and mechanism
what properties define swelling
strength of polymer-solvent interaction dictates the level of dissolution
solvation - water gets in
unfolding - water infiltrate polymer chains
swelling - an increase in hydrodynamic volume
polymer dissolution in water can be minimized by material design
material crosslinking
interpenetrating network
hydrophobic residues
material crosslinking
turns many polymer chain into one giant network, preventing chains from moving apart
interpenetrating network
uses a secondary non-swelling material as a skeleton to prevent changes in volume
hydrophobic residues
limits the ability for water to enter the system and changes to dissolve
how does swelling accelerate leaching
with the hydration of polymer chains, bulk materials are more accessible to water
penetration of water creates a path for small molecules to exit a bulk material
combination with physical forces, can induce convective transport
leachable molecules in plastic dental materials
in plastic components prone to swelling you could expect residuals from synthesis or forming of the polymer, and additive put in to achieve properties
polymer degradation
the breakdown of chemical bonds in polymer chains
shorter chains are more soluble
polymer degradation in biological environment
caused by several chemical and mechanical driving forces defined by the environment they are placed in, and their chemical structure
hydrolysis
the reverse of condensation
water breaks the polymer bond
polymer degradation via hydrolysis
polymer properties affect the ability for water to reach the site of degradation
examples of hydrolysis to provide function
resorbable sutures break down over time to eliminate need to remove
controlled drug release
corrosion and the breaking down of metals
metals are made up of ions that can be highly reactive
they can react with some biological environments and become soluble, breaking down the implant
corrosion is impacted by
material (conductivity, surface roughness, composition)
environmental (temperature, pH, cell behaviour, oxygen)
inadequate consideration of corrosion risk can lead to
compromised material function and release of byproducts that can impact biocompatibility
