Design and characterization of small-diameter tissue-engineered blood vessels constructed by electrospun polyurethane-core and gelatin-shell coaxial fiber

Substitution or bypass is the most effective treatment for vascular occlusive diseases. The demand for artificial blood vessels has seen an unprecedented rise due to the limited supply of autologous blood vessels. Tissue engineering is the best approach to provide artificial blood vessels. In this study, a new type of small-diameter artificial blood vessel with good mechanical and biological properties was designed by using electrospinning coaxial fibers. Four groups of coaxial fibers vascular membranes having polyurethane/gelatin core-shell structure were cross-linked by the EDC-NHS system and characterized. The core-shell structure of the coaxial vascular fibers was observed by transmission electron microscope. After the crosslinking, the stress and elastic modulus increased and the elongation decreased, burst pressure of 0.11 group reached the maximum (2844.55 ± 272.65 mmHg) after cross-linking, which acted as the experimental group. Masson staining identified blue-stained ring or elliptical gelatin ingredients in the vascular wall. The cell number in the vascular wall of the coaxial group was found in muscle embedding experiment significantly higher than that of the non-coaxial group at all time points(p < 0.001). Our results showed that the coaxial vascular graft with the ratio of 0.2:0.11 had better mechanical properties (burst pressure reached 2844.55 ± 272.65 mmHg); Meanwhile its biological properties were also outstanding, which was beneficial to cell entry and offered good vascular remodeling performance. Polyurethane (PU); Gelatin (Gel); Polycaprolactone (PCL); polylactic acid (PLA);1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC); N-Hydroxy succinimide (NHS); 4-Morpholine-ethane-sulfonic (MES); phosphate buffered saline (PBS); fetal calf serum (FCS); Minimum Essential Medium (MEM); Dimethyl sulfoxide (DMSO); hematoxylin-eosin (HE).