blood-biomaterial interactions exam 1 Flashcards
what are the components of blood
cells (carrying oxygen) and plasma (liquid component)
what is plasma composed of
serum + coagulation and anticoagulation proteins - fibrinogen, globulin, albumin
what is serum
plasma without fibrinogen - contains both nutrients, waste, and proteins
what are cells composed of
erythrocytes (RBCs) (most abundant), leukocytes (WBCs) (for clotting and carrying O2 for thrombosis), platelets/thrombocytes
what is hematopoiesus
formation of blood cells
what are the two types of WBCs in blood and what are they composed of
agranulocytes (monocytes and lymphocytes) and granulocytes (basophil, eosinophil, neutrophil)
what is a granzyme and what does granzyme B do
protein within granule used to identify and kill germ cells - B kills tumor cells
what is the clotting mechanism - coagulation process
intrinsic coagulation starts with vessel injury and clotting factor 12
extrinsic coagulation starts with tissue injury and factor 3
both lead to common pathway which starts w factor 5
end result: thrombin leads to fibrinogen, which gets cleaved into fibrin proteins, which are non-soluble and stick together to form a clot
what is the declotting mechanism
fibronolysis - fibrin initiates its own self distruction by releasing fibrin degradation products (FDP)
- thrombin activation signals to. tPA to secrete plasminogen, which is converted to plasmin, which interacts with fibrin to secrete FDPs
how do proteins normally assemble
with more hydrophobic amino acids at the core of the protein and more hydrophilic amino acids at the exterior of the protein (weaker interactions)
what is the Vroman effect on proteins
process of competitive protein adsorbtion to a surface by plasma proteins
how is the Vroman effect controlled
initially diffusion controlled, then later affinity controlled
albumins and fibrinogen (highest mobility) arrive first and are eventually replaced by kininogens (higher affinity for the surface)
what is the vroman effect dependent on
surface type, proteins involved, microenvironment (pH, temp)
what is protein adsorption
accumulation of adhesion molecules to a surface without penetrating the surface - 1st thing that happens when a biomaterial is implanted - changes surface properties of the biomaterial and how it’ll interact w body
what is protein adsorption driven by
energy minimization
low free energy = more stable
what are the differences for adhesion of fibroblasts to a biomaterial when hydrophobic vs hydrophilic
hydrophobic surface (i.e. HEMA) = more cell adhesion
hydrophilic surface = absorbs less proteins
what does albumin do for non-specific binding
blocks it - allows specificity through higher contraction attachments
what is biofilm
gelatinous slime layer exuded by microorganisms (bacteria/fungus) that aids in protecting them from external agents (i.e. antibiotics) by minimizing contact between the two and deactivating the activity of immune cells
what is a conditioning film
a film of proteins adsorbed first on a surface for microorganisms to stick to it and exude biofilm
how is biofilm troublesome
it promotes growth of microorganisms and may result in inflammatory/immune response to implanted biomaterials/medical devices
what are nonfouling (stealth) surfaces (NFS)
surfaces that resist the adsorption of proteins and/or adhesion of cells - usually hydrophilic
what is pegylation
a way of making a surface nonfouling
what is adhesion of blood cells on biomaterials surface preceded by
protein adsorption on the surface, which follows the Vroman effect
