Lecture 6/7 Slide Deck Flashcards
Recap: What is the main goal of biomaterial/tissue engineering?
Design and develop a bio-interface that interacts with biological systems and supports, enhances, or replaces damaged/diseased or biological function
The development of biomaterials with highly tunable properties used in different biomedical applications has been driven by the desire to replicate the structure and function of the ECM
What is the ECM?
Complex and dynamic structural scaffold for cells within tissues
Network of several macromolecules, smaller molecules, ions and water
Cells have to attach to the ECM and or other cells to function
What does the world polymer break down to?
Poly - means many
mer - means repeat unit
Polymers are long repeating units of monomers
Advantages of Polymers?
Diversity of potential physical, mechanical and chemical properties
Control over composition and physics
Easy to shape and mould
Biodegradable or permanent
Disadvantages of Polymers
Lower strength than metal and ceramics usually
Potential for deformation overtime in load-bearing
Possibility of degradation during sterilization
What are polymers defined by?
Monomer chemistry
Connectivity/bonding/structure
Molecular Weight and poly-diversity (PDI)
Bonding/crosslinking in polymers occurs via multiple types of interactions; chemical crosslinking and physical entanglements
What are crosslinking and entanglements?
Chemical Crosslinking is covalent interactions - permanent and involves the formation of covalent bonds between polymer chains
Physical entanglements - typically weaker and more reversible than covalent bonds (Hydrogen and van der Waals forces)
What properties do we look for in polymers when applying them for biomedical applications?
What phase is it in a physiological temperature?
Why is its mechanical properties in physiological conditions?
Is it water soluble / how stable is it?
What is the order of increasing strength of polymer structure?
Linear, Branched, Cross-linked and Network
How do you measure molecular weights/PDI?
Gas permeation chromatography (GPC)
GPC is a form of size-exclusion chromatography where the smallest molecules pass through bead pores resulting in a relatively long flow path
Why is polydispersity important?
If a mixture is non-uniform, not all components of a mixture contribute equally to the properties
Biocompatibility and repellency properties could highly be dependent on the chain length and surface density of the grafted polymers
What is the aim of studying biological systems like tumours?
Exploiting the unique physical properties of the tumor microenvironment in addition to it’s biological properties and designing nanoparticles that would specifically undergo physical transition at tumor conditions -> Increase the localization of the drug in tumors
