Mechanical Reinforced and Self-healing Hydrogels: Bioprinted Biomimetic Methacrylated Collagen Peptide-Xanthan Gum Constructs for Ligament Regeneration.

Collagen peptide (COP) is water soluble, bioactive, and tends to be a promising alternative to collagen for tissue regeneration. However, its low viscosity and lack of readily polymerizable groups hinder its bioprinting and limit its wide applications in tissue engineering. In this study, methacrylated collagen peptide-xanthan gum (COPMA-XG) bioinks with interpenetrating networks are developed for bioprinting stable constructs, followed by stem cell differentiation. First, self-healing COPMA hydrogels are developed with rapid UV-curing and tunable mechanical properties. To increase the printability and the mechanical properties of COPMA, XG is mixed to create a set of COPMA-XG bioinks. COPMA-XG hydrogels show self-healing properties, optimal printability, and stable morphology in the medium. The bioprinted human bone marrow mesenchymal stem cells (hMSCs) laden COPMA-XG constructs are biocompatible and bioactive, with increased production of extracellular matrix, collagen type I, and scleraxis over 28 days. Overall, bioprinted COPMA-XG constructs are versatile matrices to support hMSCs proliferation and differentiation with potential for ligament tissue engineering.