Optimizing biliary stent patency by coating with hydrophobin alone or hydrophobin and antibiotics or heparin: an in vitro proof of principle study

Although a wide range of biliary plastic and metal stents is on offer nowadays, the ideal cost-effective stent that functions permanently and that is easy to handle regarding its exchange is still not available. Therefore we tested in an in vitro model if the coating of plastic stents with hydrophobin alone or with hydrophobin and antibiotics or heparin in combination leads to an inhibition of the clogging process. We coated commercially available biliary plastic stents with hydrophobin alone, as well as with hydrophobin and antibiotics or heparin in combination. After an incubation period of 28 days in human bile, we examined the stents by scanning electron microscopy to see whether the clogging material on its surface was reduced. Coating of plastic stents with hydrophobin led to a reduction in the amount of adherent material on the surface of the stents. Coupling of ampicillin/sulbactam or levofloxacin did not lead to a further reduction of the clogging material, whereas coupling with highly concentrated heparin did reduce the adherent material. The coating of biliary plastic stents with hydrophobin or with hydrophobin and heparin in combination seems to be a promising option to delay the clogging process.