Construction of chemokine substance P-embedded biomimetic multilayer onto bioactive magnesium silicate-titanium implant for bone regeneration

Abstract

Stem cell-mediated biological processes play very important roles in bone regeneration and tissue repair. It's urgent to design new generations of tissue inductive implantable biomaterials that can regulate the biological behavior of autologous bone marrow mesenchymal stem cells (MSCs) in situ. Therefore, we designed and constructed chemokine substance P (SP)-intercalated multilayer films containing chitosan (Chi) /gelatin (Gel), which were used to cover the surface of alkaline magnesium silicate (MgSiO3)-titanium (Ti). The MgSi/LBL-SP substrate could regulate the release of SP, Mg and Si from the multilayer system as well as the resultant pH changes in a mild manner to improve the biological performance. It was demonstrated that the SP released from MgSi/LBL-SP substrate could effectively enhance MSCs recruitment in vitro and in vivo through transwell assay of MSCs migration, detection of MMP2 secretion and double immunofluorescence staining of CD29+/CD90+ markers. Meanwhile, MgSi/LBL-SP group also significantly improved the proliferation and differentiation of MSCs, which were reflected by the results of MTT assay, ALP activity, collagen secretion, ECM mineralization and western blotting. On animal models, the MgSi/LBL-SP implants displayed the highest stimulation effect on cell proliferation activity and apoptosis inhibition. Moreover, the results of histological staining and micro-CT further verified that MgSi/LBL-SP implants were more beneficial for facilitating new bone formation after implantation for 1 month. Hence, this dually optimized Ti-based implant may serve as an ideal substitute material for bone tissue repair and regeneration.