Choice Of Polymers

Question 0

Dominating property for facial reconstruction?

Answer 0

Moldability

Inertness

Question 1

Dominating property for vascular grafting?

Answer 1

Anti coagulative

Compliance

Question 2

Which polymer would you use for orthopaedic devices.

Give 4 reasons why.

Answer 2

• HDPE & UHMWPE
  1. Lubricity
  2. Strength
  3. A nominal coefficient of friction
  4. Good flexural and compressive modulus.

Question 3

Name a polymer for joints?

Why did you choose this polymer?

Answer 3

• Injection moulded pE

- Allows easy fabrication of complex contoured objects which is the case for joints.

Question 4

What are the disadvantages of PE for joint making?(3)

Answer 4

• wear and tear characteristics
• local and systemic accumulation of PE debris due to frictional erosion of articulating surface.
• thus a long term health risk.

Question 5

Delrin (dupont) is a _____\

Answer 5

Polyacetal

Question 6

Delrin application

Answer 6

As an alloplastic material in reconstruction of mandibular joints and acetabular cup prosthesis.

Question 7

Simlarity between delrin and PE

Answer 7

Tissue response same

Question 8

Disadvantage of delrin over PE? (3)

Answer 8

• Two times more friction than PE.
• 4X more dimensional change in the Delrin implants.
• leading to MORE aseptic loosening of the implant.

Question 9

Uses of polypropylene (2)

Answer 9

• Use PP meshes to repair abdominal defects.
• For DDS . PP fibres ar used as DDS for delivery of tetracyclin.
• for mandibular and malar reconstrution.

Question 10

What gives the properties to the nanomaterials?

Answer 10

• Quantum effect

- surface area to volume ratio.

Question 11

Why are nanosize scaffold better?

Answer 11

1. Increase SA to vol ratio.
2. So more cell layers.
3. Increase chemincal reactivity.

Question 12

What is a quantum dot? (3)

Answer 12

Is a nanocrystal made of semi conductor material, small enuf to show quantum mechanical properties.

Question 13

List 5 properties of QD:

Answer 13

1. Thermal pro: lowers melting temp.
2. Remarkable optical and electronic prop: in medical imaging by changing the size we can change the lamda.esp in optical imaging of fixed cells.
3. Forces of interaction: surface and interface forces dominant at nanoscale.
4. Electrical properties: at nanoscale, insulators fail to block current flow.
5. Broad tunable absorption spectrum : the qd will give a high resolution because it will emit a variety of colors.we call it photoliminescent.

Question 14

Disadvantage of QD (1)

How can you remedy this?

Answer 14

Toxic

By passivation.that is, we convey the quantum dot in a shell.

Question 15

Draw the structure of a QD

Answer 15

..

Question 16

Advantages of PEG (2)

But this is only applicable for a specific mass of peg

Answer 16

Stealth effect

Peg clearance by kidneys is slow.