Tissue engineering

Question 1

Tissue Engineering Strategy

Answer 1

1. human skeletal stem cells from patient
2. cell culture(expansion)
3. attachment to scaffold
4. cell proliferation
5. cell differentiation
6. laying down of extracellular matrix to give a biocomposite
7. Transplantation

Question 2

Define phenotype

Answer 2

characteristics that define a particular cell

Question 3

concept of ‘passage’

Answer 3

cells grow in culture until they fill the available space, they must then be divided into different flasks. Each time this happens, the cells are considered to have gone through another generation –> passage

this must be carefully monitored as aging cells will lose their phenotypic expression

Question 4

4 cell types that divide very poorly in culture

Answer 4

• chondrocytes(human cartilage)
• osteocytes
• osteoclasts
• cardiomyocytes

Question 5

How can a scaffold affect cell behaviour?

Answer 5

1. biomechanics of the surface
2. chemistry
   - –surface charge/hydrophobicity
   - –dissolution and reprecipitation of ionic species
3. Macrostructure and microstructure
   - –volume and pore interconnectivity
   - –microstructure/surface topography
   - –nanostructure/nanotopography

Question 6

Process for bone formation

Answer 6

• Attachment
• proliferation and differentiation(pre-osteoblasts)
• matrix deposition(bone formation-osteoblasts)
• tissue maturation(mineralization-osteocytes)

Question 7

Typical pore size for different scaffold applications

Answer 7

5-15um fibroblast ingrowth
40-100um osteoid ingrowth
100-200um neovascularization
350um regeneration of bone