Electrospun Polycaprolactone/Polyvinylidene Fluoride Composite Nanofibers for Fabricating Artificial Conduits for Ureteral Stricture Treatment

The ureter is a tube that carries urine excreted from the kidneys from the renal pelvis to the bladder and is of small diameter at (2–10) mm. Ureteral stricture refers to a condition in which the ureter is obstructed. Similar to arteriosclerosis and esophageal cancer patients, ureteral stenosis can also be treated by re-expanding the stenotic area using a stent or using a ureteral splint. However, even after treatment, the recurrence rate of ureteral stenosis is very high, over 80%, and has an average replacement cycle of (3–6) months. During the initial stent placement and replacement process, the patient feels great pain and, during the stent placement, also feels uncomfortable. In this study, multilayer membrane fabrication was easily performed by installing several polymer solutions at once using a high-speed electrospinning device that simultaneously operates four nozzles, not the electrospinning system commonly used in the past. In addition, we show that by using various sizes of collectors, it is possible to manufacture a small-diameter catheter of (3–10) mm similar to the actual ureter size. The functions of the electrospun PCL(CEO)/PVDF multilayer membrane manufactured in this study were confirmed according to the additives added to each layer and the polymer used. It was confirmed that the CEO added first had an antibacterial effect. In addition, it was confirmed that piezoelectric response was detected on both sides when stimulation was applied to the electrospun PCL(CEO)/PVDF multilayer membrane by the PVDF layer. The artificial catheter manufactured in this study was added with cinnamon essential oil, a representative antibacterial substance, to PCL, a biocompatible polymer, to prevent the accumulation of foreign substances and the formation of stones due to the formation of bio-sludge, which is the main cause of ureteral stricture. In addition, PVDF, a piezoelectric polymer, is coated on the PCL layer so that the PVDF layer is in contact with the actual ureter muscle. When stimulated by the flow of bodily fluid or muscle movement, PVDF piezoelectricity generates an electric current, which can have the effect of stimulating and treating malignant tumors in the ureter. The artificial conduit manufactured in this study is expected to apply both to the ureter and to blood conduits and various tissues in the body.