| 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. Reducing the number and colonization of bacteria that adhere to shunts can reduce the risk of infection. The influence of surface hydrophobicity, roughness, and functional groups on bacterial adhesion has not been fully elucidated, and reports of protein effects are conflicting. Therefore, tests of silicone coated with different biopolymers, silanes, and proteins were conducted to determine how these modifications influence Staphylococcus epidermidis adhesion and colonization under batch and flow conditions. The quality and stability of these coatings were examined by contact angle measurement, X-ray photoelectron spectroscopy, and atomic force microscopy. A colony-counting adhesion assay and scanning electron microscopy (SEM) 179 were used to quantify bacterial adhesion and colonization. FAS, OTS coated silicone, and hyaluronan coated OTS/silicone surfaces showed significantly reduced bacterial adhesion and colonization in batch condition, compared to untreated silicone by both quantification methods. Proteins immobilized on OTS/silicone surfaces significantly reduced bacterial adhesion by around 75% compared to untreated silicone, while physically adsorbed BSA on silicone reduced adhesion by only 30%. Moreover, both surface hydrophobicity and roughness have an influence on bacterial adhesion and colonization. For FAS coated on silicone, the degree of which is inversely related to surface hydrophobicity. Above a certain threshold surface roughness, rougher silicone surfaces promote bacterial adhesion and colonization. Under flow conditions, FAS, and heparin/OTS coated silicone tubing showed significantly reduced bacterial adhesion and colonization compared to untreated silicone tubing. The degree of inhibition was dependent on the level of shear rate and fluid pressure. Moreover, tubing surfaces oriented at a vertical position displayed significantly less bacterial adhesion compared to a horizontal position. These findings are helpful for devising novel strategies to reduce shunt infections. |
