Title:
Polyurethane Biomaterials
Polyurethane Biomaterials
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Authors
Cooper, Stuart
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Abstract
Polyurethanes have gained acceptance in the biomedical field because they have good
physical properties and biocompatibility. The name “polyurethane” describes a class of
polymers that can be synthesized to possess a variety of properties, from hard to brittle
to very elastic. The polyurethanes that have found use in biomedical applications have
elastomeric properties accompanied by good toughness, tear resistance and abrasion
resistance. They have been widely used in application such as the artificial heard and
pacemaker lead insulation, among others. The role of polyurethane’s surface in the
blood-material interaction will be described. Surface properties believed to affect
biocompatibility include the interrelated properties of hydrophobicity, polarity and
surface charge. The presence and mobility of microdomain surface morphologies may
also affect protein adsorption and thrombus formation. In an attempt to use polyurethanes in more demanding applications, we have been
modifying their structure to include functional groups, which have the potential to
exhibit bioactivity. Polyurethanes containing sulfonate groups exhibit hydrogel and
anticoagulant behavior compared to unmodified polyurethanes. The sulfonated
polyurethanes affect the ability of fibrinogen to polymerize and they consume
thrombin, an important enzyme in the coagulation pathway. Progress in understanding the interactions of the Arg-Gly-Asp (RGD) peptide sequence
and integrins has stimulated a great deal of interest in the development of novel
biomaterials, which may improve endothelial cell attachment and growth. Rather than
immobilization of peptide to the polymer surface, an alternative approach was taken in
that a polyurethane block polymer was modified so that it contained free carboxyl
groups (PEU-COOH). Two cell adhesive peptides, GRGDSY (based on the fibronectin
sequence, RGDS) and GRDVY (based on the vitronectin sequence RGDV), and an
inactive peptide GRGESY were then grafted to the polyurethane backbone through the
formation of amide linkages. The effects of peptide incorporation on polymer surface
properties and endothelial cell adhesion were evaluated.
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Date Issued
2011-11-09
Extent
56:42 minutes
Resource Type
Moving Image
Resource Subtype
Lecture