Figure 3.

Fabrication of a tissue-engineered bionic urethra. A unlabeled and USPIO-labeled tissue-engineered bionic urethra were fabricated by wrapping a silicone tube with a stack of three types of cell sheets in a carefully planned order (a and b). As a control, cell-free SIS was also wrapped around the silicone tube (c) and transplanted to subcutaneous area. The length of bionic urethra is 2.5 cm and its diameter is 4 mm (d). The yellowish-brown in USPIO-labeled tissue-engineered bionic urethra is due to the characteristic color of iron nanoparticles (e). The bionic urethra was auto-transplanted into subcutaneous space of groin for 3 weeks (f). Three weeks after subcutaneous transplantation, for tissue-engineered bionic urethra (g) and cell-free SIS (h), the retrieved implant maintained a good cylindrical shape and mechanical strength better than prior to transplantation due to the growth of tissue around the implant. The autologous buccal mucosa is the material commonly used for urethra reconstruction in the clinical setting, the size is 2.5 cm×1.0 cm (i).