Cell-Laden Constructs with Anisotropic Pores Fabricated by Collagen/Silk-Fibroin for Muscle Tissue Regeneration

Abstract

Advancements in bioprinting technology, driven by innovations in bioink formulations, have made it possible to create tissue-engineered constructs that closely replicate the intricate structures of native tissues. Despite the development of numerous cell-laden bioinks, three critical challenges remain: (1) achieving adequate porosity, (2) mimicking the anisotropic morphology of native tissues, and (3) maintaining mechanical properties sufficient for structural integrity. Although previous studies using collagen-based foam bioinks have addressed the issue of porosity, the enhancement of mechanical properties and anisotropic physical structure remains limited. In this study, silk fibroin (S-F) is integrated with collagen to form an interpenetrating polymer network with improved mechanical strength. In addition, a stretching technique is applied to generate anisotropic morphological features, producing biocomposites with enhanced mechanical and structural properties suitable for muscle tissue regeneration. The resulting cell-laden constructs demonstrated significantly improved cellular activities, including myogenic differentiation, which are attributed to their anisotropic oval shapes, aligned collagen fibrils, and mechanical stimulation. These properties are assessed using in vitro and in vivo experiments. The findings suggest that anisotropically porous collagen/S-F constructs offer a versatile platform for anisotropic tissue regeneration, effectively bridging the gap between physical structure and biological function in tissue engineering.