Biomaterials Test 2

biodegradable time frame

6 months

advantages of synthetic polymers:

no immune response, reproducible, wide range of properties

what is km?

the substrate concentration at half reaction rate

in 0 order reactions…

reaction concentration doesn’t matter

in 1st and 2nd order reactions…

concentration of reactants does matter

what are the modes of biodegradation?

surface erosion and bulk degradation

surface erosion is when

the material degrades from the surface in, becomes smaller as it happens, loses mass faster

bulk degradation is when…

more water infiltration, whole material is degraded.

ezymatic degradation is…

either bulk or surface,
enzymes do the degradation through reactions

enzymatic degradation is determined by..

location, concentration, and enzyme kinetics

biodegradation is

degradation that involves biological processes, such as bodily fluids, cell activities, or enzymes, and is influenced by biological environment

hydrophilic polymers degrade _______ than hydrophobic polymers (and why?)

faster, water can get in to break it down faster

amorphous degrades _____ than semi-crystalline

faster

polymers with high tg degrade _____ than polymers with low tg

slower

The ester bond is…

carbon double bonded to an oxygen, and bonded to an oxygen

mechanisms of chemical degradation… (list three)

breaking cross links, removing pendant groups, breaking the backbone

hydrophobic polymers degrade by…

surface erosion

hydrophilic polymers degrade by…

bulk degreadation

polyanhydrides

hydrophobic, fast, non toxic

poly(ortho esters)

more hydrophobic, slower

poly( alpha - hydroxy esters)

PLA, PGA, PLGA, broken down by hydrolysis

an ester bond next to a thioether group is ______ susceptible to degradation than an unmodified one.

more

_____ is a prerequisite for degredation to occur

water

poly(ortho esters), polyanhydrides, polyesters are ______ degradable polymers

hydrophobic

hydrolytic surface erosion/bulk degradation means…

degradation through water

all natural polymers degrade by…

enzymatic degradation 

enzymatic degradation can be….

surface erosion or bulk degradation

for enzymatic degradation, surface erosion occurs in

hydrophobic and hydrophilic polymers

for enzymatic degradation, bulk degradation occurs in

hydrophilic polymers (where enzyme infiltrates and is evenly spread through bulk or the rate of enzymatic bond cleavage is slower than enzyme infiltration)