Exam 1

Question 1

factors that are used to classify medical devices

Answer 1

invasiveness and time spent within the body

Question 2

biomaterials

Answer 2

materials used within the body to replace or heal body tissues and/or functions

Question 3

three classes of biomaterials

Answer 3

metals, ceramics, and polymers

Question 4

factors that go into material choice

Answer 4

bulk property similarity, surface property similarity, processability, and FDA regulation

Question 5

bulk properties

Answer 5

mechanical, diffusion, optical, electrical (brain, muscles, heart, etc.)

Question 6

surface properties

Answer 6

biomaterials should be inert (chemically inactive) so as to not elicit a host response

Question 7

processability

Answer 7

how easily can it be manufactured?

is it commercially viable to produce?

Question 8

FDA regulation

Answer 8

tested for safety and efficacy

Question 9

biocompatibility requirements

Answer 9

must be able to be in contact w/ living tissue without:

• causing harmful tissue reaction that would compromise their function (pain, swelling, necrosis)
• causing a systemic toxic reaction (immune rejection)
• having tumorigenic potential

Question 10

tumorigenic potential

Answer 10

difficult to show since tumor formation occurs over time

ex: flaking off of polymers in polymer-metal joints (these may be suitable for older patients since it normally takes about 10 years for negative effects)

Question 11

type 1 diabetes

Answer 11

beta cells are destroyed and do not secrete insulin

Question 12

potential treatment methods for diabetes using biomaterials (brainstorming)

Answer 12

insulin delivery

beta cell protection

replacement of dead beta cells

Question 13

stent function

Answer 13

improve blood flow created by plaque

metal mesh is put around balloon and inflated in blood vessel

Question 14

questions to ask when working with biomaterials

Answer 14

why are there different biological responses to the same materials?

how does the body respond to foreign materials?

how does the body judge between foreign and self?

how do cells see?

Question 15

how do cells see?

Answer 15

cells “see” via proteins

proteins cause a signaling cascade that causes behavior changes in the cell

proteins are polymeric chains of amino acids

Question 16

primary structure

Answer 16

amino acids

primary bonding types: ionic, covalent, and metallic

Question 17

secondary structure

Answer 17

alpha helix or beta sheets via molecular interactions such as: dipole-dipole, hydrogen bonds, polar molecular induced dipole, or fluctuating dipole

Question 18

tertiary strucutre

Answer 18

polypeptide chain or protein folding

Question 19

quaternary structure

Answer 19

assembled, multiprotein subunits

Question 20

protein adsorption

Answer 20

dissolved, soluble proteins in solution will deposit onto the surface of another object

creates a new “surface” and identity that can be recognized by the body

Question 21

protein adsorption spontaneity

Answer 21

favorable and irreversible process

Question 22

enthalpy

Answer 22

heat or bond energy that is present in a system

affected by charges

Question 23

entropy

Answer 23

disorderedness of a system

increases when moving from “one” to “many”

Question 24

how can enthalpy change?

Answer 24

changes in bond energy in protein due to structural changes

amount of energy between the surface and protein

amount of energy between the protein and material surface with other molecules in solution (ex: blood)

Question 25

general change in enthalpy in protein adsorption

Answer 25

enthalpy is generally positive but not as large compared to entropy energy of bonds formed is greater than energy of bonds lost (not necessarily referring to quantity of bonds changed)

Question 26

how does the rate of protein adsorption change as the surface becomes covered?

Answer 26

rate of protein adsorption slows initial adsorption rate on a clean surface is high further adsorption occurs as molecules rearrange to create new free surface (ex: protein layer may go from wide and short to tall and skinny)

Question 26

how does the rate of protein adsorption change as the surface becomes covered?

Answer 26

rate of protein adsorption slows initial adsorption rate on a clean surface is high further adsorption occurs as molecules rearrange to create new free surface (ex: protein layer may go from wide and short to tall and skinny)

Question 27

ionic bonding

Answer 27

transfer of valence electrons

Question 28

covalent bonding

Answer 28

sharing of valence electrons

Question 29

metallic

Answer 29

delocalization of valence electrons

Question 30

why does protein adsorption lead to an increase in entropy?

Answer 30

as proteins adsorb to the surface, this frees up water molecules to move around, creating disorder/an increase in entropy

Question 31

low entropy is...

Answer 31

unfavorable

Question 32

if your surface is somewhat hydrophobic, is protein adsorption favorable?

Answer 32

yes proteins that adsorb will "kick out" the ordered water and decrease the unfavorable water-surface interaction

Question 33

forming an ionic bond reduces...

Answer 33

enthalpy