Blood-Material Interactions

Question 1

How do you identify the macrophages in this image?

Answer 1

• size of macrophage
  fixme insert annotated picture

Question 2

What are two vital functions of macrophages?

Answer 2

1. Recognize cells as ‘self’ or ‘not self’
2. Phagocytosis (engulfing other cells)

Question 3

What type of cell is a neutrophil?

Answer 3

Immune cell

Question 4

What does the immune system do?

Answer 4

• Mobile
• Find bacteria
• Chemotaxis (movement of a cell/organism)

Question 5

What are the 8 steps in the body’s response to injury?

Answer 5

1. Injury
2. Blood-biomaterial interaction
3. Provisional matrix formation
4. Acute (short-term) inflammation
5. Chronic (long-term) inflammation
6. Granulation tissue
7. Foreign body reaction
8. Fibrous capsule formation

Question 6

True or False:

Surgery alone is an injury.

Answer 6

True

Question 7

A fibrous capsule forms around an implant. Afterward, how does it integrate with the surrounding tissue?

Answer 7

It doesn’t become part of the tissue. It’s walled off.

Question 8

What is the sequence of cell types in response to an implanted biomaterial?

Answer 8

1. Neutrophils
2. Monocytes
3. Macrophages
4. Fibroblasts and foreign body giant cells
5. Myofibroblasts

Question 9

What are the 5 stages of healing after a biomaterial is implanted?

Answer 9

1. Biomaterial implantation
2. Protein adsorption
3. Macrophage adhesion
4. Encapsulation
5. Capsular contracture

see this picture for more information

Question 10

What is the immune system doing during the homeostasis phase of wound healing?

Answer 10

Processes:

• Coagulation

Cells/Molecules/Tissues

• Platelets
• Fibrin

Question 11

What is the immune system doing during the inflammation phase of wound healing?

Answer 11

Processes:

• Immune infiltration
• Debris clearance
• Pathogen killing

Cells/Molecules/Tissues

• Neutrophils
• MQ (Macrophages)
• Lymphocytes

Question 12

What is the immune system doing during the profileration phase of wound healing?

Answer 12

Processes:

• Fibroblast proliferation
• Scar formation
• Collagen synthesis
• Angiogenesis

Cells/Molecules/Tissues

• Proteoglycan
• Fibroblast
• Collagen

Question 13

What is the immune system doing during the remodeling phase of wound healing?

Answer 13

Processes:

• Epithelialization
• ECM remodeling
• Scar maturation/contraction
• Apoptosis

Cells/Molecules/Tissues

• Epithelium
• Endothelium

Question 14

The homeostasis phase of wound healing lasts:

A. hours
B. days
c. weeks
d. months/years

Answer 14

A. hours

Question 15

The inflammation phase of wound healing lasts:

A. hours
B. days
c. weeks
d. months/years

Answer 15

B. days

Question 16

The proliferation phase of wound healing lasts:

A. hours
B. days
c. weeks
d. months/years

Answer 16

c. weeks

Question 17

The remodeling phase of wound healing lasts:

A. hours
B. days
c. weeks
d. months/years

Answer 17

d. months/years

Question 18

How do cells sense and interacts with a foreign object, such as an implant?

Answer 18

Protein interactions

Question 19

Designing how proteins bind to the ________ controls how the body reacts to the implant

A. implant
B. cells
C. body

Answer 19

A. implant

Question 20

True or False:

Blood-implant interactions regulate cell-implant interactions.

Answer 20

True

Question 21

What are two biomaterial properties that regulate adsorption?

Answer 21

• surface hydrophobicity
• surface charge

Question 22

What happens if you change an implant’s surface hydrophobicity?

Answer 22

• Dehydration of the surface and protein (H₂O molecules are rearranged)
• Structural arrangements of proteins (2, 3, 4 structure)

Question 23

What happens if you change an implant’s surface charge?

Answer 23

• Redistribution of charged groups
• Structural arrangements of proteins (2, 3, 4 structure)

Question 24

What are five biomaterial properties that regular adsorption?

Answer 24

• Topology
• Composition
• Hydrophobicity
• Heterogeneity
• Potential

Question 25

What is the effect of changing the **topology** property of an **implanted biomaterial**?

Answer 25

More texture means more surface area, which means more interaction sites.

Question 26

What is the effect of changing the **composition** property of an **implanted biomaterial**?

Answer 26

Chemical groups will determine types of interactions with proteins

Question 27

What is the effect of changing the **hydrophobicity** property of an **implanted biomaterial**?

Answer 27

Hydrophobic surfaces tend to bind to more proteins

Question 28

What is the effect of changing the **heterogeneity** property of an **implanted biomaterial**?

Answer 28

Non-uniform surface properties leads to surface domains that can interact differently (*some +/- charges are rough/smooth) fixme check this

Question 29

What is the effect of changing the **potential** property of an **implanted biomaterial**?

Answer 29

Electrochemical potential - distribution of ions in solution and interaction with proteins *release to charge + protein shape + entropy* fixme check this

Question 30

What are four protein properties that regulate protein adsorption?

Answer 30

- size - charge - hydrophobicity - stability (structure)

Question 31

What is the effect of changing the **size** property of a **protein**?

Answer 31

Big molecules have more sites for contact

Question 32

What is the effect of changing the **charge** property of a **protein**?

Answer 32

Molecules with charge generally adsorb more readily

Question 33

What is the effect of changing the **hydrophobicity** property of a **protein**?

Answer 33

Hydrophobic molecules adsorb to hydrophobic surfaces *like* binds to *like*

Question 34

What are **two** effects of changing the **stability** property of a **protein**?

Answer 34

- Less conformationally stable proteins can unfold more and form more surface contact points - Molecules that unfold more rapidly can form contact points more rapidly

Question 35

On [this image](https://1drv.ms/i/s!AplQmb0Y4yamkKpXvNZa3FGmauGMJA?e=BiW1QG), identify the regions where the protein will interact with the solid.

Answer 35

[Picture](https://1drv.ms/i/s!AplQmb0Y4yamkKpYlPBXILInMMr9vg?e=v2TPB3)

Question 36

What is the vroman effect?