Plastic stents can occlude and require reintervention in up to 75% of cases and this has contributed to more frequent use of much more expensive metal stents. Efforts to increase the duration of plastic stent patency, such as antibacterial stent and hydrophilic coating or design modifications, have met limited success. We hypothesize that a biocompatible liquid-impregnated surface (LIS) coating combining a textured substrate with a liquid lubricant creates a lubricious surface that reduces cell attachment and biofilm formation. Our aim is to determine the ability of LIS coating in an in vitro model to reduce thrombus formation and lumen occlusion.
A polyethylene (PE) tube, made with the same material and size as a 10 Fr biliary stent, is coated with a LIS coating. A Chandler loop assay with freshly harvested bovine blood is used to analyze cell attachment and thrombus formation. Pressure buildup within either PE tubes or 5 Fr polyurethane tubes in presence of whole blood is tested with an occlusion assay. The coated devices are challenged with bile extract solution at 38 °C up to 35 days. The surface composition is analyzed by Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR).
LIS-coated tubes demonstrated a 100% thrombus reduction using the Chandler loop assay (Figure 1a). The coating remained stable on the surface up to 35 days both in air and in the bile acid solution (Figure 1b,c). LIS-coated tubes were observed to remain patent after 12 hours of swine bile infusion, compared to controls that were completely obstructed. The coated surfaces also reduced occlusion rates in bovine blood (Figure 2).
With a formulation developed through thermodynamic and hydrodynamic validation, a biocompatible LIS coating was applied on a model GI device both internally and externally. In addition to the anti-thrombogenic and antimicrobial performance, the slippery characteristics of the coating can reduce friction, facilitate device deployment during implantation. The coating has the potential to be applied on a GI device such as a biliary stent for a further product development.