EXAM 2 Flashcards
Surface free energy
Drives surface interactions – materials want to reduce to it
High surface energy
More wettable (hydrophilic) – Less protein adsorption
Low surface energy
Less wettable (hydrophobic) – Less protein adsorption
Surface topography
Rough + hydrophilic = more wetting
Rough + hydrophobic = “Lotus effect” (more hydrophobicity)
Surface properties that matter
Topography, charge, chemical composition, molecular mobility, contamination risk
Protein adsorption
Approach – protein comes near surface
Attachment – initial binding
Arrangement – spreads out, makes more contact
Additions - replacement / rearrangement of proteins
Vroman effect
Sequential displacement: small, fast proteins arrive first but are replaced by larger, higher affinity ones
Factors that effect adsorption
Surface hydrophobicity (more = more adsorption, denaturation)
Protein size (larger = more binding contacts)
Orientation & unfolding = impact cell behavior & recognition
High concentration = fast adsorption but weaker binding
How is some protein adsorption food?
Helps will cell attatchement
Steps of Blood-material Interactions
- Protein adsorption
- Contact activation
- Complement activation
- Platelet adhesion & activation
- Provisional matrix
Acute inflammatory response
Neutrophils: First responders, short-lived, can form NETs
Monocytes → become macrophages (M0)
Macrophages: M1 (pro-inflammatory), M2 (repair)
Phagocytosis
Enhanced by opsonins like IgG/C3b.
Frustrated phagocytosis
If material too big → enzymes released → tissue damage.
NETosis:
Neutrophils release DNA traps for pathogens
Chronic Inflammation & FBR
Begins about 1 day post-implant
Characterized by granulation tissue, macrophages, fibroblasts
