Composite thin film and electrospun biomaterials for urologic tissue reconstruction.

A replacement material for autologous grafts for urinary tract reconstruction would dramatically reduce the complications of surgery for these procedures. However, acellular materials have not proven to work sufficiently well, and cell-seeded materials are technically challenging and time consuming to generate. An important function of the urinary tract is to prevent urine leakage into the surrounding tissue--a function usually performed by the urothelium. We hypothesize that by providing an impermeable barrier in the acellular graft material, urine leakage would be minimized, as the urothelium forms in vivo. However, since urothelial cells require access to nutrients from the supporting vasculature, the impermeable barrier must degrade over time. Here we present the development of a novel biomaterial composed of the common degradable polymers, poly(ε-caprolactone) and poly(L-lactic acid) and generated by electrospinning directly onto spin-coated thin films. The composite scaffolds with thin films on the luminal surface were compared to their electrospun counterparts and commercially available small intestinal submucosa by surface analysis using scanning electron microscopy and by analysis of permeability to small molecules. In addition, the materials were examined for their ability to support urothelial cell adhesion, proliferation, and multilayered urothelium formation. We provide evidence that these unique composite scaffolds provide significant benefit over commonly used acellular materials in vitro and suggest that they be further examined in vivo.