Supportive features of a new hybrid scaffold for urothelium engineering

Different clinical conditions can compromise the urinary bladder function and structure. Routine regenerative practices in urology for bladder augmentation have been associated with diverse side effects. The internal lining of the bladder, the urothelium, plays an integral role in normal bladder function. Tissue engineering has provided novel therapeutic strategies through scaffolding and cell transplantation. Nano-scale surface features of scaffolds are valuable parameters for enhancement of cell behavior and function.

We fabricated a new hybrid scaffold of poly ɛ-caprolactone (PCL) and poly-L-lactide acid (PLLA) using an electrospinning system to exploit each polymer's advantages at nano-scale in the same scaffold. Dog urothelial cells were isolated, characterized by immunocytochemistry, and expanded for loading on the scaffold. Cell viability and proliferation on the scaffold surface were assessed by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Furthermore, cytoarchitecture, distribution and detailed morphology of cells, and expression of cell specific markers were examined using hematoxylin and eosin (H + E) staining, scanning electron microscopy (SEM), and immunohistochemistry, respectively.

According to MTT results, the scaffold did not exert any cytotoxic effect, and also supported cell proliferation and viability for 14 days of culture, which led to a significant increase in the number of cells. Scanning electron microscopy images revealed evenly distributed and normal appearing colonies of urothelial cells. A well-defined layer of cells was observed using H + E staining, which preserved their markers (pan-cytokeratin and uroplakin III) while growing on the scaffold.

Our findings confirmed favorable properties of PCL/PLLA regarding biocompatibility and applicability for upcoming new methods of bladder augmentation and engineering.