Exam Flashcards
2A) a. Bone tissue responses to the mechanical loading in orthopaedic implants
i. The reduction of bone desity as a result of removal of normal stress from the bone by the implant. It’s vital to choose materials with similar mechanical strength to the bone tissue and making the implant structure more flexible would be a way to reduce the stress shielding
3A) Basic understanding of a biosensor
(highest likelihood)
i. Biocompatible
ii. Stable
iii. Fast response time ideally a real-time response
iv. Linear relationship
v. High specificity
3C) Molecular interactions present in hydrogels
i. Hydrogen bonding
ii. Covalent bonding
iii. Ionic bonding
3D) Differing nanoscale drug delivery methods (with understanding )
i. Limpsomes: surfactant bilayer membrane enclosing small droplet of aqueous solution
ii. Nanoparticles: Nano-sized solid polymer molecule with entrapped drug
iii. Nanocapsules: Polymer shell enclosing a small droplet of oil
iv. Polymer-drug conjugates: A polymer with a covalently bound drug molecule
3E) Importance of using nanotechnology
i. Drug may pass into the cell
ii. Improved therapeutic index
iii. Drug kept in circulation for a longer period of time
3F) Structural feature requirements with an example
i. The polymer should be cationic so it can complex and condense DNA
ii. Poly(L-lysine) is a good example of a polymer that can do this
4A) Illustrate different stages of a typical host response to an implanted foreign body giving the timescales
1sec to 1 hr - protein adsorption
30mins to two days - cells attack biomaterial
2days to 10 days - giant cell formation & cytokines released
3+weeks - dense, avascular collagen capsule formed
4B) Blank slate approach and how it can be used
i. Blank slate approach is used to study cell surface interactions
ii. Involves a non-adhesive
iii. Surface decorated with a protein or peptide
iv. Cells will only see the attatched protein or peptide & not any non-specific proteins that have been absorbed
v. Hence cell behaviour can be dirrectly correlated with what you have attatched
4C) Upcell’s cell sheet engineering approach with example
i. Smart biomaterial used known as PNiPAAm
ii. PniPAAm shows LCST behaviour
iii. Increasing temperature causes polymer to become more hydrophobic and percipritates.
iv. Happens because temperautre makes hydorgen bonding unfavourable compared to polymer-polymer & water-water interactions
v. PNiPAAm is used as a surface coating and is hydrophilic below LCST & hydrophobic above LCST.
vi. Used to control cell attatchment for cell sheet engineering
vii. Cells cultured above the LCST then temperture is dropped to below 32 degrees causing cells to detatch
4D) +/- using full protein or a short peptide sequence
i. Functionalisation with full protein:
1. Proteins are fragile
2. Proteins are expensive
3. Immunogencity of proteins is higher than peptide
4. Protein may allow for secondary peptide interctions
5. Possess conformation
ii. Functionalisation of peptides
1. Higher stability
2. Easily charecterised
3. Smaller which corrolates to a higher surface density
4. Single peptide can selectively select particular cell receptors
4E) Understanding of templating and non-templating methods
i. Non-templating method:
1. Thermally induced phase separation (TIPS)
2. Cast a solution of the polymer in an organic solvent into a mould and change the temperture.
3. The solvent & polymer become incompatible & phase separate into polymer-rich phase & solvent-rich phase.
4. Solvent creates pores in the solid polymer phase
5. Remove the solvent by evaporation to leave behind a porus scaffold material
ii. Templating method:
1. Polymerised high internal phase emulsion (HIPE)
2. Formulation of HIPE followed by polymeristation of its continous phase.
3. Once polymerised the continous phase of the HIPE contracts allowing droplets to connect with nearby droplets
4. Leads to fully interconnected low density polymer foam known as polyHIPE
