Overview of Tissue Engineering

Question 1

What are scaffolds in tissue engineering?

Answer 1

Structure made of biomaterials that acts as a template for tissue formation

Question 2

What 3 primary components integrated together make up tissue engineering?

Answer 2

• Cells
• Scaffolds
• Signals

Question 3

Name a few different types of scaffolds

Answer 3

• Decellularised organs
• Synthetic biomaterials
• Natural biomaterials
• Metals

Question 4

Explain the process of decellularizing and reseeding an organ

Answer 4

1) Decellularize the organ which created an acellular scaffold containing all the structural proteins, proteoglycans and polysaccharides
2) Seed the scaffold with cells and culture in a bioreactor providing nutrient rich media

Question 5

Give some examples of cell signals and what are they used for?

Answer 5

To promote cell growth
- Growth factors and hormones
- Chemotactic factors (proteins that attract cells to a specific location to grow)
- Biomechanical signals (stretching, compression, loading)
- Electrical stimulation

Question 6

What are some important considerations when designing a scaffold for a broken leg?

Answer 6

• The scaffold must match the mechanical properties of the tissue it is replacing
• The use of growth factors, bioactive materials, and cells
• The level of movement and activity the host will be doing after the operation
• The degradation rate of the implant (if at all), the surface topography or porosity

Question 7

What are the essential requirements of a scaffold?

Answer 7

• To mimic the structure and biological function of the healthy tissue its replacing
• In terms of chemical composition, mechanical properties so that it can recapitulate the same environment

Question 8

Name 2 synthetic Biomaterials:

Answer 8

PLA (Coated in bioactive glass in the image)
PDLA and PLLA

Question 9

Name 3 natural biomaterials and their origin

Answer 9

• Collagen - fish skin
• Silk - spider webs/ silk worms
• Elastin - Animal tissues like aorta

Question 10

Explain again what a decellularised extracellular matrix scaffold is?

Answer 10

• A biomaterial formed by human or animal organs that have had the immunogenic cellular components removed via decellularized technologies

Question 11

What are some advantages of using a decellularised matrix over other scaffold options?

Answer 11

1. Preserves native ECM architecture.
2. Reduced immune response.
3. Retains bioactivity and signalling cues.
4. Customizable to specific tissue types.
5. Biodegradable over time.
6. Versatile for various tissue engineering applications.

Question 12

What are dECM scaffolds made of?

Answer 12

ECM macromolecules such as:
- Collagen
- Elastin
- Fibronectin
- Laminin
- Matricellular proteins

Question 13

What are the roles of Collagen and Elastin in a dECM?

Answer 13

Collagen: Provides the tensile strength of the framework

Elastin: Provides the elasticity

Question 14

What are the roles of Fibronectin and Laminin in a dECM?

Answer 14

Fibronectin: Regulates cell behaviour and function and guides morphogenesis (the shape and structural development of cells)

Laminin: Promotes cell adhesion and migration by offering bioactive sites on the ECM for cells to cross link and attach (like the glue for cells)

Question 15

What is the purpose of matricellular proteins in a dECM?

Answer 15

• They do not play a role in providing structural support
• They modulate cell signalling, adhesion, migration and proliferation

Question 16

What are organ derived dECM scaffolds?

Answer 16

Scaffolds obtained from specific organs or tissues, which posses the natural 3d architecture from the whole organ or tissue

Question 17

Explain how a organ derived decellularised ECM is made and then reimplanted

Answer 17

1) The organ or tissue is extracted from the host
2) The organ is decellularised
3) Specialised differentiated cells cultured in-vitro are seeded onto the organ, recellularisation
4) implantation of the decellularized organ/tissue