The influence of conditioning film on antifouling properties of the polyurethane film modified by chondroitin sulfate in urine

Abstract

The encrustation and induced infection severely impact on the therapeutic effectiveness and service life of urinary stents due to the fast formation of conditioning film on urinary stents after implantation. The composition and properties of conditioning film have great influence on antifouling properties of stent materials. In our previous work, we modified polyurethane films by chondroitin sulfate (PU-CS) with different CS grafting densities to verify its anti-fouling properties. To obtain the in-depth understanding of encrustation on urinary stents, we investigated the impact of the composition and properties of conditioning film on the following inorganic salt deposition and bacteria adhesion in urine. The results showed that quantity of proteins and polysaccharides in conditioning films, and the roughness, water contact angle and zeta potential of PU-CSs covered with corresponding conditioning film decreased with the increase of CS grafting density on PU films.PU-CS(3) with highest CS grafting density (3.70g/cm2) had the highest bacteria inhibition rate and least inorganic salt deposition among the PU-CSs in artificial urine. Moreover, inorganic salts depositing on the PU-CS(3) were less and smaller than those on other films. Bacteria were not detectable until day 21 in real urine. Meanwhile, the pH value was elevated. The results suggested that the component of conditioning films was more important than other surface properties such as hydrophilicity, zeta potential and roughness for inorganic salt deposition and bacteria adhesion. Moreover, the anti-encrustation properties of the surface was promoted by proteins and inhibited by polysaccharides.