Questions you couldn't answer

Question 1

Chain silicates

Answer 1

• Silicate minerals containing chains

Question 2

Bone substitute using bioglass

Answer 2

BioGlass is used in a powder form to encourage bone healing

This occurs because it forms hydroxyapatite which encourages cell adhesion and releases calcium

Question 3

How do we control fouling

Answer 3

-Make the surface hydrophobic

Question 4

3 different degredation mechanisms of biodegradable polymers

Answer 4

Environmental 
- UV light 
- Heat 
- 
Biodegredation- enzymes 
- Lipase- released on inflammation - breaks down PCL
- Protease 
- Amylase
-Oxidase/reductase
Biodegredaton- Cells 
-Hydoxyl radicals are highly toxic and aid macrophages in the killing of invading micrfoorgamnisms. They occur due to an introduction of a foreign body and act as part of the bodies defence mechanism. PLA and PCL degrade faster in the presence of these radicals

Question 5

Why has there been metal on metal implant recall

Answer 5

• Often used in young active patients
• The devices experienced high short term failure rates
• Adverse reactions with metal on metal implants is assosciated with the destruction of soft tissue as well as bone
• This soft tissue destruction is often irreversible meaning poor revision procedures
• A few patients also develop systemic symptoms from exposure to high exposure to metal ions

Question 6

What methods do we have to make surfaces hydrophobic to control fouling

Answer 6

Decrease the surface energy because this means a high contact angle so the water has a high surface energy meaning a low degree of spreading –> Hydrophobic

We could also create surface brushes of extremely hydrophillic materials on the surface

Question 7

Differences between 2D and 3D cell culturing

Answer 7

• Cell migration is different
• in 2D plate cells are confined
• no resistance to migration in 3D, better proximity to other cells as would be in a real body tissue
• The ideal environment should mimic the mechanical and biochemical environments whilst facilitating processes such as migration and tissue organisation
• 3D exhibit higher degrees of structural complexity and homeostasis which is analogous to tissues and organs

2D structures are sometimes better because

• Easier to control environment
• Cell observation is easier- including viewing with a microscope (also improves measuring)

Question 8

Does a biomaterial break down faster in vivo or in vitro

Answer 8

Biomaterials break down faster in vivo due to the larger number of biological forces being exerted on them
More physical and chemical stress put on the object

IN VIVO

• Environmental degredation - hydrolysis, photolysis, heat
• Biodegredation- enzymes
  
  • a combination of enzyme and bacterial degredation
• Biodegredation - Cells
  
  • Inflammation can lead to an increase in the number of hydroxyl radicals which leads to and increase in biopolymer degredation rate. Both PLA and PCL degrate faster in the presence of these radicals

Question 9

Hydrogel based biosensor

Answer 9

IS THIS A GLUCOSE RESPONSIVE HYDROGEL
Boronic acid binds to glucose and then a quencher releases a fluuorescent tag in the hydrogel - been examples seen in mouse ears

Question 10

Two examples of implant failure

Answer 10

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Question 11

Invitro tests that identify whether a biomaterial releases soluble

Answer 11

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