Foreign Body Reaction
The presence of the implant changes the healing response, and this is
called the Foreign Body Reaction.
FBR consists of:
 protein adsorption
 multinucleated foreign body giant cells
 fibrous encapsulation
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Components of Plasma
Component
Typical Concentration (mg/100 ml)
protein
7250
salts
325
lipids
828
glucose
90
urea
25
carbohydrates
85
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Proteins
are polyamides, composed of amino acids
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Soluble Proteins
(A) A space-filling model of myoglobin with hydrophobic amino acids shown
in yellow, charged amino acids shown in blue, and others shown in white.
The surface of the molecule has many charged amino acids, as well as
some hydrophobic amino acids. (B) A cross-sectional view shows that
mostly hydrophobic amino acids are found on the inside of the structure,
whereas the charged amino acids are found on the protein surface.
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albumin
Protein Adsorption
CHEE 872
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Protein Adsorption and Cell Response
Vroman Effect
From: An Introduction to Tissue-Biomaterial Interactions, Wiley, 2002.
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Wound Healing in Presence of Biomaterial
protein adsorption mediates neutrophil and macrophage response
Den Dunnen et al. J Biomed Mater Res 36 (1997) 337
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Frustrated Phagocytosis
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Foreign Body Response
 continuing presence of an implant may result in the
attainment of a final steady-state condition called resolution
 there are 3 possible outcomes for the implant :
» resorption
» integration
» encapsulation (fibrosis)
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Example
in vivo response to
implanted biodegradable
elastomer
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Experimental Results
poly(trimethylene carbonate)
elastomer implanted s.c.
in rats
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