Potential Load-Bearing Bone Substitution Material: Carbon-Fiber-Reinforced Magnesium-Doped Hydroxyapatite Composites with Excellent Mechanical Performance and Tailored Biological Properties

Abstract

A potential load-bearing bone substitution and repair material, that is, carbon fiber (CF)-reinforced magnesium-doped hydroxyapatite (CF/Mg-HAs) composites with excellent mechanical performance and tailored biological properties, was constructed via the hydrothermal method and spark plasma sintering. A high-resolution transmission electron microscopy (TEM) was employed to characterize the nanostructure of magnesium-doped hydroxyapatite (Mg-HA). TEM images showed that the doping of Mg-induced distortions and dislocations in the hydroxyapatite lattice, resulting in decreased crystallinity and enhanced dissolution. Compressive strengths of 10% magnesium-doped hydroxyapatite (1Mg-HAs) and CF-reinforced 1Mg-HAs (CF/1Mg-HAs) were within the range of that of cortical bone. Compared with 1Mg-HAs, the fracture toughness of CF/1Mg-HAs increased by approximately 38%. The bioactivity, biocompatibility, and osteogenic induction properties of Mg-HAs and CF/Mg-HAs composites were evaluated in vitro using simulated body fluid (SBF) immersion, cell culture, osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and expression of genes associated with osteogenesis. When Mg-HAs were immersed in SBF, Mg2+ continued to release for up to 21 days. Mg-HAs demonstrated a satisfactory ability to induce apatite formation in comparison with HAs. The cell proliferation and morphology on CF/1Mg-HAs were similar to those of 1Mg-HAs, suggesting that adding CF had no adverse effect on cellular activity. The expression levels of osteogenesis-related genes [osteocalcin (OPN), osteopontin (OCN), and runt-related transcription factor 2 (Runx2)] on 1Mg-HAs were significantly higher at days 3 and 7 than those on HAs and 0.5Mg-HAs groups. This finding suggests that a certain amount of Mg doping had beneficial influences in the different stages of osteogenic differentiation and could induce osteogenic differentiation of BMSCs. The new bone volume to total volume ratio of implanted 1Mg-HAs (30.9% ± 4.1%) and CF/1Mg-HAs (25.4% ± 5.4%) was remarkably higher than that of HAs (21.6% ± 3.9%). 1Mg-HAs and CF/1Mg-HAs tailored an ideal effect of new bone information and implant osseointegration. The excellent mechanical performance and tailored biological properties of CF/Mg-HAs were attributed to nano Mg-doped HA, CF reinforcing, refined microstructure, and controlled composition.

Group Replacement–Rearrangement-Triggered Linear-Assembly Nonaqueous Precipitation Synthesis of Hydroxyapatite Fibers

“…In addition, weak peaks ascribed to CO characteristic of CO 3 2– appear at 865, 1437, and 1452 cm –1 , forming a small amount of carbonate-substituted apatite . This phenomenon is caused by the adsorption of carbon dioxide in the atmosphere by highly active hydroxyapatite crystals with polar groups removed by boiling holding treatment with kerosene, resulting in a small almount of carbonate apatite, which has excellent biological activity and biocompatibility . These also prove the application prospect of this material in carbon capture.…”

Synthesis Technology of Magnesium-Doped Nanometer Hydroxyapatite: A Review

“…The nHA prepared by Zhao et al 118 by the hydrothermal method is hexagonal, and the average length and width of the particles are about 100 and 30 nm, respectively. The average length and width of Mg-nHA prepared in the same way are about 80 and 30 nm.…”

“…The aspect ratio of the nanoparticles was found to decrease with increasing Mg content, which is thought to be caused by the suppression of grain growth and lattice distortion when the Mg element is substituted in nHA. 118 In the hydrothermal synthesis of Mg-nHA composite with an acid–base slow-release agent at pH = 3 and a temperature of 180 °C, Zhang et al 119 found that with the increase of Mg 2+ content. This is mainly because the radius of Mg 2+ (70 pm) is smaller than that of Ca 2+ (100 pm).…”

Biphasic Calcium Phosphate and Activated Carbon Microparticles in a Plasma Clot for Bone Reconstruction and In Situ Drug Delivery: A Feasibility Study

“…The main limitation of these carbon nanomaterials is their size, which is generally less than 200 nm, with the risk of being eliminated by the human immune system or the target organ [18][19][20]. We and others have shown that ACs, under the form of carbon fibers, are interesting materials for bone reconstruction [21][22][23][24][25][26]. In pilot studies performed in a rat model of large bone cortical defects, we have shown that activated carbon fiber cloth is highly biocompatible and fully osteointegrated after 6 months post-surgery [27].…”