blood-biomaterial interactions exam 1

Question 1

what are the components of blood

Answer 1

cells (carrying oxygen) and plasma (liquid component)

Question 2

what is plasma composed of

Answer 2

serum + coagulation and anticoagulation proteins - fibrinogen, globulin, albumin

Question 3

what is serum

Answer 3

plasma without fibrinogen - contains both nutrients, waste, and proteins

Question 4

what are cells composed of

Answer 4

erythrocytes (RBCs) (most abundant), leukocytes (WBCs) (for clotting and carrying O2 for thrombosis), platelets/thrombocytes

Question 5

what is hematopoiesus

Answer 5

formation of blood cells

Question 6

what are the two types of WBCs in blood and what are they composed of

Answer 6

agranulocytes (monocytes and lymphocytes) and granulocytes (basophil, eosinophil, neutrophil)

Question 7

what is a granzyme and what does granzyme B do

Answer 7

protein within granule used to identify and kill germ cells - B kills tumor cells

Question 8

what is the clotting mechanism - coagulation process

Answer 8

intrinsic coagulation starts with vessel injury and clotting factor 12
extrinsic coagulation starts with tissue injury and factor 3
both lead to common pathway which starts w factor 5
end result: thrombin leads to fibrinogen, which gets cleaved into fibrin proteins, which are non-soluble and stick together to form a clot

Question 9

what is the declotting mechanism

Answer 9

fibronolysis - fibrin initiates its own self distruction by releasing fibrin degradation products (FDP)
- thrombin activation signals to. tPA to secrete plasminogen, which is converted to plasmin, which interacts with fibrin to secrete FDPs

Question 10

how do proteins normally assemble

Answer 10

with more hydrophobic amino acids at the core of the protein and more hydrophilic amino acids at the exterior of the protein (weaker interactions)

Question 11

what is the Vroman effect on proteins

Answer 11

process of competitive protein adsorbtion to a surface by plasma proteins

Question 12

how is the Vroman effect controlled

Answer 12

initially diffusion controlled, then later affinity controlled

albumins and fibrinogen (highest mobility) arrive first and are eventually replaced by kininogens (higher affinity for the surface)

Question 13

what is the vroman effect dependent on

Answer 13

surface type, proteins involved, microenvironment (pH, temp)

Question 14

what is protein adsorption

Answer 14

accumulation of adhesion molecules to a surface without penetrating the surface - 1st thing that happens when a biomaterial is implanted - changes surface properties of the biomaterial and how it’ll interact w body

Question 15

what is protein adsorption driven by

Answer 15

energy minimization

low free energy = more stable

Question 16

what are the differences for adhesion of fibroblasts to a biomaterial when hydrophobic vs hydrophilic

Answer 16

hydrophobic surface (i.e. HEMA) = more cell adhesion
hydrophilic surface = absorbs less proteins

Question 17

what does albumin do for non-specific binding

Answer 17

blocks it - allows specificity through higher contraction attachments

Question 18

what is biofilm

Answer 18

gelatinous slime layer exuded by microorganisms (bacteria/fungus) that aids in protecting them from external agents (i.e. antibiotics) by minimizing contact between the two and deactivating the activity of immune cells

Question 19

what is a conditioning film

Answer 19

a film of proteins adsorbed first on a surface for microorganisms to stick to it and exude biofilm

Question 20

how is biofilm troublesome

Answer 20

it promotes growth of microorganisms and may result in inflammatory/immune response to implanted biomaterials/medical devices

Question 21

what are nonfouling (stealth) surfaces (NFS)

Answer 21

surfaces that resist the adsorption of proteins and/or adhesion of cells - usually hydrophilic

Question 22

what is pegylation

Answer 22

a way of making a surface nonfouling

Question 23

what is adhesion of blood cells on biomaterials surface preceded by

Answer 23

protein adsorption on the surface, which follows the Vroman effect