Week 11 Flashcards
materials found in biological systems (e.g., nature) that could be used in biomedical applications
natural biomaterials
What are two examples of natural biomaterials?
- jade stones –> replace tooth
- coral –> bone graft
What are the 4 advantages of natural biomaterials?
- cell attachment
- enhance mechanical properties of synthetic biomaterials
- bind and deliver macromolecules
- improved biocompatibility
What are 3 disadvantages of natural biomaterials?
- increased immunogenic
- structural complexity
- degraded by enzymes
What are 3 applications of natural biomaterials?
- tissue engineering
- regenerative medicine
- wound healing
- antibacterial coatings - medical devices
- bioprosthetic implants
- heart valves
Natural biomaterials can mimic the properties of what two materials?
- polymers
- ceramics
What are 5 examples of protein-based natural biomaterials?
- collagen
- gelatin
- silk fibroin
- fibrin
- elastin
What are 7 examples of polysaccharide-based natural biomaterials?
- chitosan
- starch
- alginate
- hyaluronan
- chondroitin
- sulfate
- dextran
This type of natural biomaterial is a protein that is exclusively found in animals and is the most abundant protein in the human body
collagen
What is collagen a part of?
extracellular matrix
What is the main function of collagen?
provide structural support for connective tissues
What are the two primary features of collagen?
- act as glue connecting tissues
- strength and structural integrity
What is the primary protein of the skin?
collagen
Collagen is a type of connective tissue found in what 4 parts of the body?
- bone
- dentin
- tendon
- ligaments
Collagen makes up ___% of muscle tissue
1-2%
How many different types of collagen have been identified?
28
Each different molecular type of collagen is unique in what 4 ways?
- composition
- structure
- function
- tissue specificity
What are the two major types of collagen which make up 90% of the collagen in the body?
- Type I
- Type V
What type of collagen is found in dentin?
Type I
Describe the hierarchy of collagen
amino acids –> expand and grow and form helices –> tropocollagen –> crosslinking –> fibrils –> multiply fibrils –> fibers
What is the primary function of cross-linking?
side-by-side packing of fibrils to increase strength
What happens if cross-linking is inhibited?
tensile strength is drastically reduced
What happens to the amount of cross-linking as you age?
it increases
Describe the mechanical response of collagen
this is what the trend will look like if you apply a stress to break the collagen fiber
“toe region” –> tangled and you begin to stretch it
“linear region” –> collagen fibers are all in a line with eachother
“failure” –> collapse
What is the most abundant type of collagen in the human body?
type I
What type of collagen is the predominant form used in biomaterials application?
type I
Where are 8 places type I collagen is found?
- skin
- dentin
- cornea
- blood vessels
- bone
- tendon
- ligament
- fibrocartilage
What does type I collagen aggregate into?
fibrils
What does the diameter of type I collagen depend on?
- age
- tissue
(50 nm - 500 nm)
Describe type I collagen in teeth
forms a dense network array of individual thin fibrils, with an interfibrillar matrix
type II collagen
Where is type 2 collagen found?
articular cartilage
What 4 things is type II collagen made of?
- proteoglycans
- glycoprteins
- non-collagenous proteins
- water
What two things does the fibrillar network of type II allow?
- cartilage to entrap proteoglycan aggregate
- provide tensile strength to tissue
Another name for type II collagen
cartilage