Fiber-reinforced gelatin-based hydrogel biocomposite tubular scaffolds with programmable mechanical properties

Tissue-engineered tubular scaffolds (TETS) provide an effective repair solution for human tubular tissue loss and damage caused by congenital defects, disease, or mechanical trauma. However, there are still major challenges to developing TETS with excellent mechanical properties and biocompatibility for human tubular tissue repair. Gelatin-based hydrogels are suitable candidates for tissue-engineered scaffolds because they are hydrolyzed collagen products and have excellent biocompatibility and degradability. However, the mechanical properties of gelatin-based hydrogels are relatively poor and do not align well with the mechanical properties of human tubular tissues. Inspired by the extracellular matrix architecture of human tubular tissues, this study utilizes high-precision 3D printing to fabricate ultrafine fiber network tubular scaffolds (UFNTS) that mimic the arrangement of collagen fibers, which are then embedded in a cell-compatible gelatin-based hydrogel, resulting in the preparation of a fiber/hydrogel biocomposite tubular scaffold (BCTS) with tunable mechanical properties and a J-shaped stress-strain response. Finite element analysis was employed to predict the mechanical behavior of the UFNTS and BCTS. Experimental results indicate that by modifying the structural parameters of the UFNTS, the mechanical properties of the BCTS can be effectively tuned, achieving a programmable range of tensile modulus (0.2-4.35 MPa) and burst pressure (1580-7850 mmHg), which broadly covers the mechanical properties of most human tubular tissues. The design and fabrication of BCTS offer a new approach for the development of TETS while also providing a personalized strategy for such scaffolds in tissue engineering.