Surface Properties of Biomaterials Flashcards
What is the International Organization for Standardization (ISO)?
an organization in an effort to harmonize biocompatibilty testing and developed a standard for biological evaluation of medical devices
What is surface tension?
excess energy caused by regions or atoms at the surface not bonded, unfilled valence shells
What is adsorption?
adhesion of molecules to a solid surface
What is absorption?
penetration of molecules into the bulk of another material (example : water absorbed into a sponge)
What is biocompatibility
controlling protein adsorption to the surface of biomaterial
What are the four interactions on the surface of a material?
surface tension, adsorption, absorption, biocompatibility
What can protein adsorption on the surface of a biomaterial cause? (4)
more proteins to attach, inflammatory response, cellular interaction therefore inhibiting proliferation, biofilm formation
What are the two properties that impact adsorption?
surface hydrophobicity and surface charge
what increaseswith increased surface hydrophobicity?
protein adsorption
what occurs by the dissociation of ionizable surface groups or through adsorption of ions from a solution?
surface charge
what can trap proteins
surface roughness
What are the three techniques to analyze surfaces?
atoic force microscopy (AFM), scanning electron microscopy (SEM), contact angle analysis
what does contact angle analysis determine?
hydrophobicity of a surface
what are the two surface treatments
chemical surface modification and biological surface modification techniques (covalent bonding to surface & non covalent bonding)
what is chemical vapor deposition?
mix of gases is exposed to material at high temperature causing decomposition of components in gas mixxture and subsequent deposition
what is physical vapor deposition?
deposition of atoms generated through physical processes, it increases water resistance of metallic implants
what are the steps for a layer by layer coating in non covalent bonding
- positively charged subrate placed in anionic colution
- rinsed to remove loosely attahed material
- negatively charged surface is placed in cationic solution, adsorption of positively charged material occurs
- substrate is rinsed again
what is covalent biological coatings
attaching biologically active molecules to substrates through covalent bonds
what are non covalent biological coatings?
involves adsorption of the biomolecule into the biomaterial then cross-linking to improve the coating stability
