Preparation And Anti-encrustation Performance Of A Polyurethane/Chondroitin Sulfate Film

The encrustation and induced infection severely impact on the clinic therapeutic effectiveness and service life of urinary stents with long-term indwelling. The fast formation of conditioning film on urinary stents after implantation is one of the critical facts for encrustation. Polyurethane (PU) have been widely used for ureteral stent because of its good biocompatibility and excellent physical and mechanical properties. However its intrinsic hydrophobility is favorable for proteins adsorption and bacteria adhesion which may cause encrustation and induce infection. The surface modification of PU will be one of the best trategy to solve these problems.In this paper, chondroitin sulfate (CS) with hydrophilic and negetive charge was introduced onto PU surface by chemical grafting with the diamine, as a spacer. The modified PU-CS films were comprehensively characterized and obtained. The effects of surface constructure and phsical properties on protein and glycosaminoglycan adsorption, formation of conditioning film, inorganic salt deposition, and bacteria adhesion were investigated. The results indicated that the PU-CS films, especially the films with N-Boc-1,3-propanediamine as a spacer, showed better hydrophilic, and PU-CS(3) had the best protein resistence activity because of its largest grafting amount of CS. Furthermore, the formation of conditioning film on PU-CS was inhibited. The amount of proteins and glycosaminoglycans adsorption was decreased. After formation of conditioning film, the proteins promoted the inorganic salt deposition, while glycosaminoglycans inhibited the crystal growth. It was founded that the amount of inorganic salt deposition on PU-CS(3) was smallest on day 7. Simultaneously, the PU-CS film had relativly less bacteria adhesion than unmodified PU film. Simiarly, the increase amout of protein and the decrease amount of glycosaminoglycans in conditoning film was benefial to bacteria adhesion. And the combination of effect of the protein and glycosaminoglycans allowed the PU-CS(3) film to have best property of anti-bacteria adhestion. The above results will provide expermental basis for future surface modification of urinary stents. The design for surface with the anti-protein adsorption and glycosaminoglycans adsorption will greaty promote the anti-encrustation on urinary stents.