Biological performance of two materials based on sulfated hyaluronic acid and polyurethane

Abstract

Polyurethane bound with sulfated hyaluronic acid was synthesized by two different chemical routes. Both the materials obtained consist of a hydrophilic component, sulfated hyaluronic acid (HyalS _3.5 ), and a hydrophobic component, polyurethane (PU). In the material named Puhmdi, the HyalS _3.5 was cross-linked to the PU chains via hexamethylene diisocyanate (HMDI) while in that named Pubrac, the binding of HyalS _3.5 to the PU chains occurred only through a few carboxy groups viaN,N′-dicyclohexylcarbodiimide (DCC) and bromoacetic acid.The surface characteristics of the polymers were investigated by ATR FT-IR spectroscopy while the surface morphology was analyzed by scanning electron microscopy.There was a significant difference between the surface characteristics of the films in dry and hydrated environments. In both materials the hydrophilic component (HyalS _3.5 ) migrates from the bulk to the surface, thus minimizing the surface free energy of the polymer when exposed to the hydrated environment. The different biological behavior of the two materials was demonstrated with the thrombin time test and platelet adhesion test. Pubrac inhibits the coagulation process while Puhmdi does not.