Biocompatible polymer film

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a co-polymer film which can be applied over a surface of an article to form a continuous surface that is more biocompatible and has a smoother surface morphology than an untreated article.
In general the co-polymer film of the invention can be formed by providing a hydrophobic polymer block, such as polydimethylsiloxane (PDMS) with functional --OH end groups and reacting the --OH ends with a conventional monomer or prepolymer of a film-forming polymer capable of reacting with --OH groups.
Such reactions are exemplified, using as reactive PDMS a triblock copolymer of the polylactone-polysiloxane-polylactone (PL-PDMS-PL) type, or silicone polyesters.
The --OH groups of the polylactone blocks can react with any of a variety of isocyanates in a suitable solvent to form a polymer having PDMS incorporated with its structure.
The film can be applied to the surface of an article by any convenient means of coating the article with the reaction mixture in solvent, and allowing the solvent to evaporate.
A polymeric film having PDMS blocks incorporated within the polymer forms over the coated surface.
The resulting film is mechanically stronger than coatings of PL-PDMS-PL alone.
The film integrity makes it possible to encase any structure made of any material compatible with solvents used to dissolve the starting materials.
Materials can be chosen for their optimal mechanical properties, then an article made of the desired material can be encased in a polymeric film of the invention to render the article biocompatible.
The polymeric films of the invention are further advantageous in that they can reduce surface roughness which may exist in the article.
As an example, in polyurethane-based catheters, barium sulfate is added to provide x-ray contrast.
The barium sulfate increases the surface roughness, which can degrade the biocompatibility, induce flow turbulence or enhance cellular or microbial deposits.
The polymer film applied to the catheter surface not only increases the biocompatibility by changing the chemical composition of the surface, but also by reducing the roughness of the surface