475ae In Vitro and in Vivo Studies of Staphylococcus Epidermidis Adhesion and Colonization on Modified Silicone Surfaces

Haiying Tang1, Kelley Brabant2, Xuemei Liang1, Ting Cao1, Anfeng Wang1, Steven O. Salley1, James P. McAllister II2, and K. Y. Simon Ng1. (1) Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Dr., Detroit, MI 48202, (2) Department of Neurological Surgery, Wayne State University, 4201 Antoine Street, UHC-6E, Detroit, MI 48201

Hydrocephalus affects about one out of every 1000 births and is treated with cerebrospinal fluid (CSF) “shunt” catheters. However, complications with CSF shunts often occur. Infection is a major complication of cerebrospinal fluid (CSF) shunting procedures. In our previous studies, we have successfully modified silicone surfaces to reduce bacterial adhesion by as much as 75% under static in-vitro conditions. The objective of this research is to investigate the efficacy of these modified surfaces under in-vitro pulsatile flow environment, and in-vivo studies. In the in-vitro experiment, a perfusion model at 37 °with pulsatile flow (20 ml/ hour , simulate the typical CSF flow in shunts)will be used to evaluate the effect of modified shunts on amount of bacterial adhesion. Three different modified surfaces, Fluoroalkylsilane (FAS)-silicone, heparin- octadecyltrichlorosilane (OTS)-silicone, and hyaluronan-OTS-silicone will be studied. In addition, the effect of shunt valves on overall adhesion will be investigated. In the in-vivo study, these modified silicone samples will be implanted in the lateral ventricle of the rats for 10, 28 or 90 days. Upon sacrificing the rates, the implanted samples will be retrieved and analyzed using a scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and colony counting methods. The results of this study will provide a direct correlation of the efficacy of coated silicone under static, pulsatile, and in-vivo conditions; thus lead to optional strategies to develop novel shunts to minimize bacterial adhesion.