Artificial Bone Grafts

Question 1

Properties of an ideal scaffold for regenerative scaffolds

Answer 1

• promote tissue growth
  interconnected macroporous network for vascularisation, tissue ingrowth and nutrient delivery
• bond to the host tissue without the formation of scar tissue
• Resorb at the same time as the tissue is repaired
• Provide signals to the cell

Question 2

Can bioglass be used as a scaffold?

Answer 2

No it cannot be made porous, the reaction will occur too early because Bioglass reacts to water

Question 3

Properties to consider when manufacturing an artificial bone graft

Answer 3

1. pore size
2. interconnect size
3. mechanical properties
4. degradation time
5. biological response

Question 4

List 4 bioresorbable natural polymers

Answer 4

collagen
gelatin
chitosan
alginates

Question 5

Metal foams: Can metals be bioactive?

Answer 5

• Ti can be treated with NaOH to produce surface Ti-OH groups
• TiO2 layer
• When placed in solution supersaturated in calcium phosphate, an HCA layer can form
• This is a coating method - not bioactivity

Question 6

Applications of synthetic bone grafts

Answer 6

Craniotomy, shoulder arthroplasty, herniated disc

Question 7

Actifuse, what is the manufacturing process?

Answer 7

Gel cast foaming

1. powder slurry + gelling agent
2. foaming with the aid of surfactant –> bubbles
3. in situ gelation
4. sintering and burn out of organics

Adv 
structure (pores) - good mimic of the bone 
biodegradation 
mechanical properties 
does not form hollow structs

Disadv
difficult process

Question 8

What is the space holder process?

Answer 8

porogen(baking soda) + metal/ceramic slurry then sintering

Question 9

What is the salt leaching process?

Answer 9

porogen(salt) + polymer solution in solvent then sintering