Application of a Strontium-Loaded, Phase-Transited Lysozyme Coating to a Titanium Surface to Enhance Osteogenesis and Osteoimmunomodulation

Abstract

Background To fabricate strontium (Sr)-incorporated titanium (Ti) surfaces by a novel 1-step phase-transited lysozyme (PTL) treatment, and investigate the effects of the prepared samples on osteogenesis and osteoimmunoregulation. Material/Methods Five groups of titanium specimens were prepared, including Ti, PTL, PTL@10Sr (PTL coating with 10 mg/mL Sr), PTL@20Sr PTL coating with 20 mg/mL Sr), and PTL@50Sr (PTL coating with 50 mg/mL Sr) groups. Behaviors of bone marrow mesenchymal stem cells (BMSCs) such as initial attachment, spread, proliferation, and migration, on different surfaces were examined by immunofluorescence, MTS assay, and Transwell system. Then the osteogenic differentiation of BMSCs was detected. When an immune response was factored in, the polarization of macrophages induced by the prepared surfaces was detected by real-time PCR, and the response of BMSCs to macrophage-conditioned medium was assessed in terms of cell migration and osteogenic differentiation. Finally, an in vivo study was performed, using the rat femora implant model, to evaluate the potential for osteogenic induction and osteoimmunoregulation of materials. Results Our in vitro experiments indicated that PTL coating could improve cell spread and adhesion, and the stable Sr release of PTL@Sr layers could promote cell migration and osteogenesis. Moreover, PTL@Sr surface could regulate the immune response of macrophages resulting in enhanced BMSCs recruitment and osteogenic differentiation. The in vivo evaluation showed less inflammatory infiltration and improved bone formation in the PTL@20Sr group. Conclusions The Sr-loaded PTL layers have greater potential for the induction of osteogenic differentiation of BMSCs, meanwhile Sr-loaded PTL layers could adjust the immune response and thus promote osteogenesis both in vitro and in vivo .

Effects of Strontium-Doped β-Tricalcium Scaffold on Longitudinal Nuclear Factor-Kappa Beta and Vascular Endothelial Growth Factor Receptor-2 Promoter Activities during Healing in a Murine Critical-Size Bone Defect Model

“…On the other hand, NF-κB activity tended to decrease in the latter phase of fracture healing in both the non-scaffolded as well as the β-TCP-scaffolded group, but in the strontium (+ Sr) group, by contrast, NF-κB activity shows a significant increase beginning around day 40 after the fracture. The immunomodulatory properties of Sr is discussed in some studies [25,33], but as far as we know, such an anti-inflammatory effect of strontium has never been reported in a study featuring longitudinal monitoring. Acute inflammation is a crucial biological process for tissue homeostasis in the early phase of fracture healing.…”

Facile preparation of functional and hybrid coatings by precipitations of polypyrrole and lysozyme via co‐assembly process

“…According to the peeling test, the weight loss of the pure PPy substrate and PPy/PTLP composite are 17.53% and 3.80% comparing to the original mass respectively, indicating that the adhesion of PPy/PTLP composite is higher due to the bio‐adhesive of lysozyme 45 . The lysozyme deposition is rich in amyloid assembly structure, which may have hydrophobic interaction force, hydrogen bonding, and electrostatic effect with unique bio‐adhesion property 42–44 …”

“…It is reported that lysozyme can be transmitted to assembled nanoparticles with self‐adhesion on various substrates via a phase transition process 42 . This assembly may act as a template and induce the aggregation of organic/inorganic materials to generate homogenous hybrids 2,42–44 . During the assembled process, the lysozyme nanoparticles may deposit on different substrates in aqueous environmental 42,45–49 .…”

Interleukin-4 assisted calcium-strontium-zinc-phosphate coating induces controllable macrophage polarization and promotes osseointegration on titanium implant

“…Chen et al [ 9 ] and Wang et al [ 37 ] found that the strontium phosphate (including strontium apatite, strontium hydrogen phosphate) coatings on the surface of a magnesium (Mg) alloy can promote proliferation and differentiation of human mesenchymal stem cells and MC3T3E1 cells in vitro, as well as induce further bone formation in vivo. It has also been reported that the Sr-loaded phase-transited lysozyme (PTL) coating invokes greater osteogenesis ability by its effects on the immune environment due to the constant release of Sr ions directly at the implant-tissue interface [ 38 ]. Su et al [ 39 ] discovered that the Zn ion that exist in the form of zinc phosphate, plays a key role in improving osseointegration and immune regulation.…”