3D-bioprinted vascular scaffold with tunable mechanical properties for simulating and promoting neo-vascularization

Abstract

Alternative artificial vessels with tissue-matching mechanical and biological performance have been continuously taking great attention in bioengineering. However, it is challenging to take into account both mechanical and biological properties in formulating a hydrogel material. In the current study, a composite hydrogel ink based on geltain-methacryloyl (GelMA) and sodium alginate (SA) was prepared by a two-step polymerization process, and its fast shaping was realized by stabilizing the alginate fraction in calcium ion bath as well as the photo-crosslinking of GelMA. Mechanical properties of the transparent 3D printing GelMA/Gelatin/SA blood vessels were determined by testing their stretching and resilience performance. Based on Von Mise stress simulation using Ansys, strain of the artificial blood vessels reached 147% and the elastic Young’s modulus reached approximately 224 ​kPa in the optimal hydrogel formulation, matching well with capability of enduring certain blood pressure encountered in real tissue. A selective and uniform permeability of hydrogel tubes was presented by using small molecules and human red blood cells, meanwhile excellent hemolysis, cell viability, and proliferation ability were also verified. Based on the results of in vitro assessment and the in vivo transplantation in SD rats, our proposed GelMA/Gelatin/SA vessels, with tissue-matching mechanical properties and their ideal biodegradation behavior, promoted neo-vascularization capacity and showed promising potential in producing an artificial blood vessel.