Development of an in vitro ventricular shunt material testing model and utility of PEG as antifouling coating

Abstract

OBJECTIVE CSF shunts, most commonly the ventriculoperitoneal shunt, remain a first and last line of management for children and adults with hydrocephalus. However, the failure rates of these shunts are extremely high, leaving many patients with the need for revision surgical procedures. The objective of this study was to develop a model to assess the efficacy of a nonfouling ventricular catheter. A second objective was to test polyethylene glycol (PEG) as an antifouling coating. METHODS Microglial cells were grown on medical-grade catheter silicone with biofouling simulated by collagen incubation over a range of concentrations from 31 to 103 µg/ml and durations from 2 to 18 hours. After ideal fouling conditions were identified, catheter silicone was then coated with PEG as an antifouling surface, and cell growth on this surface was compared to that on uncoated standard catheter silicone. RESULTS Collagen biofouling increased cell growth on silicone surfaces with an ideal concentration of 69 µg/ml and incubation of 6 hours. PEG coating of silicone catheter material yielded 70-fold lower cell growth (p < 0.0001), whereas collagen-fouled PEG-coated silicone yielded 157-fold lower cell growth (p < 0.0001). CONCLUSIONS Catheter coating significantly reduced cell growth, particularly in the setting of biofouling. The application of antifouling surfaces to ventricular shunts shows considerable promise for improving efficacy.