Biomaterials

Question 1

PMMA

Answer 1

Poly(Methyl methacrylate)

Question 2

UHMWPE

Answer 2

Ultra-High-Molecular-Weight-Polyethylene

Question 3

Issues with Hip Implants

Answer 3

Dislocation
Osteolysis
Metal Sensitivity

Question 4

What Therapeutic Ways Do We Use Biomaterials?

Answer 4

Replace
Repair
Support
Improve
Storage
Diagnosis
Monitoring

Question 5

Common Classes of Biomaterials

Answer 5

Metals
Ceramics
Polymers
Composites
Biologics

Question 6

Metals

Answer 6

Pros: Strong; tough; ductile; conducts electricity
Cons: May corrode; difficult to make
Examples: Joint replacement; bone plates and screws; electrodes

Question 7

Ceramics

Answer 7

Pros: Strong in compression; Biocompatible; Wear-resistant
Cons: Brittle; Not resilient
Examples: Dental and joint replacement; Coatings for dental and orthopedic implants

Question 8

Polymers

Answer 8

Pros: Easy to fabricate and manipulate; Resilient; Can be made transparent
Cons: Not too strong; Can deform with time
Examples: Sutures; Blood vessels; Soft tissues; Lenses

Question 9

Composites

Answer 9

Pros: Tailor-made
Cons: Difficult to make
Examples: Carbon-fiber reinforced UHMWPE; Particle-reinforced bone cement

Question 10

Important material properties

Answer 10

Bulk, Surface, and Biological

Question 11

Metal Examples

Answer 11

Titanium Alloys, Cobalt Chrome, Platinum

Question 12

Ceramic Examples

Answer 12

Quartz, Alumina

Question 13

Bioceramic Examples

Answer 13

Alumina, Porcelain, Hydroxyapatite, Bioglass

Question 14

Polymer Examples

Answer 14

Silicone, Polyethylene, pHEMA, PTFE, PGA

Question 15

Biodegradables

Answer 15

Must Break Down: Safely and reliably; Relatively quickly; By biological means; Into raw materials of nature; Disappear into nature

Question 16

Biodegradation Mechanisms

Answer 16

Hydrolysis and Enzymatic Degradation

Question 17

4 Steps of Degradation

Answer 17

1) Water adsorption and hydrolysis
2) Reduction of molecular weight (polymer length)
3) Reduction of mechanical properties (modulus and strength)
4) Diffusion and phagocytosis by macrophages

Question 18

Natural biodegradables

Answer 18

Naturals/Biologics, Fibrin, Collagen, Hyaluronic Acid

Question 19

Stress of Metals

Answer 19

Linear Elastic Region; Yield Strength Point; Deformation; Breaking point

Question 20

Normal Injury and Healing Steps

Answer 20

1) Injury
2) Bleeding and clotting
3) Provisional Matrix Formation
4) Acute Inflammation
5) Chronic Inflammation
5) Granulation Tissue Formation
6) Tissue Remodeled to Original State

Question 21

Healing after Biomaterial Implantation Steps

Answer 21

1) Injury
2) Blood-Material Interactions
3) Provisional Matrix Formation
4) Acute Inflammation
5) Chronic Inflammation
5) Granulation Tissue Formation
6) Foreign Body Reaction
7) Fibrous Capsule Development

Question 22

Macrophages

Answer 22

• Phagocytic cell
• Removes cellular debris
• Becomes frustrated by the presence of foreign materials
• Becomes multinucleated and releases inflammatory cytokines and reactive oxygen intermediates (ROI)

Question 23

Biomimetic Coatings

Answer 23

Coat implant with biocompatible material
Passive: Low protein binding surfaces; PEG; Alginate
Active: Heparin (anti-coagulant) coated surfaces

Question 24

Types of Implant Response Resolution

Answer 24

1) Resorption- material degrades
2) Integration- implant and host tissue grow together
3) Encapsulation- implant surrounded by fibrous tissue

Question 25

Biocompatability Testing

Answer 25

Cyto-Compatibility (Cyto-toxicity) via in vitro testing then animal studies