Nanotechnology-derived catheters for reduced inflammation and infection

Abstract

Polydimethylsiloxane (PDMS) has been used for short- and long-term catheters. However, PDMS shunt tubing has been scrutinized recently because of their extremely high failure rates (such as their use to treat hydrocephalus). While there are many reasons why PDMS shunt systems fail, one is tissue occlusion of the ventricular catheter, most often caused by macrophages. Infection is also problematic. Nevertheless, few attempts have been made to detect and to manipulate shunt catheter inflammation and infection. It is hypothesized that nanotextured and nanotubular surfaces can be carefully manipulated to inhibit immune cell (specifically, macrophages) and bacteria responses. The objective of this study was to create PDMS molds of titanium (Ti) anodized to possess nanotubes and test inflammatory and bacteria responses on such substrates. Previous studies have determined decreased inflammation and bacteria growth on anodized compared to unanodized Ti. As expected, nano-sized tubes were distributed uniformly on the Ti surface after anodization. The uniform pores, as observed by scanning electron microscopy, were estimated to have a diameter of 50-60nm and a depth of 200nm. After pouring the PDMS slurry onto the surface of the nanotubular Ti and peeling off the first PDMS template, a nanopatterned structure was observed. In addition, the PDMS replica showed exactly the same nanotubular features as anodized Ti. In conclusion, a PDMS template obtained from anodized nanotubular Ti was achieved and demonstrated a promising ability to inhibit macrophage and bacteria functions.