Catheters are used in clinical urological practice when other methods of managing incontinence fail. Ideally, they should resist bacterial colonization and encrustation of calcium and magnesium mineral deposits. The catheters presently in use suffer from the above two problems causing infections, strictures and pain to the patients. The encrustation is caused by urease producing bacteria; the action of urease on urea results in ammonia production, resulting in increased urine pH. Alkaline pH causes the precipitation of calcium and co-precipitated magnesium products. During Phase I, we made a new composite material with covalently attached reactive organic functionalities. These surfaces are hydrophilic and show very low adhesion of P.Mirabalis and P.Vulgaris, fifty times lower than the silicone and Teflon coated latex catheter materials. Similar results were observed in encrustation experiments carried out with bacteria as well as urease. There is good correlation between bacterial adhesion and encrustation in some of our most promising preliminary materials. Phase II work proposed here aims to build on the Phase I results: optimization of the formulations, detailed bacterial adhesion and encrustation studies, characterization of leachates, in vitro material qualification tests and in vivo experiments with a rabbit model are proposed.
| Sarangapani, S; Cavedon, K; Gage, D (1995) An improved model for bacterial encrustation studies. J Biomed Mater Res 29:1185-91 |
