Biofabrication and evaluation of 3D printed and cast PCL / collagen-alginate hydrogel tubular scaffolds for urethral...

The urethra is a fibromuscular tube that transports urine from the bladder to the exterior of the body. Congenital disorders and urethral wall strictures caused by traumatic injuries, infections, iatrogenic injuries, and tumor removals can impair urethral function. This research aimed to create a 3D printed scaffold of the urethra using casting and 3D printing techniques, and then the constructed scaffolds were characterized. The final scaffolds consisted of a 3D-printed mesh made of poly-ε-caprolactone (PCL) that was cast with a hybrid hydrogel of collagen-alginate and crosslinked. The swelling of hydrogels containing more alginate in the structure eventually led to the collapse of the hydrogel skeleton. The gradual increase in the compressive strength of the hydrogel scaffolds was consistent with the rise in alginate hydrogels. Rheological properties clearly showed shear-thinning behavior for samples containing more alginate. The viability of rat bladder smooth muscle cells in the CA82 hydrogel (collagen:alginate 8:2 v/v) was higher than in the CA37 hydrogel (collagen:alginate 3:7 v/v). In addition, the expression of functional genes of rat smooth muscle cells was improved in the CA82 hydrogel. The described method and fabricated scaffold could provide a promising approach for urethral reconstruction by tissue engineering.