Controlled SrR Delivery by the Incorporation of Mg Particles on Biodegradable PLA-Based Composites (original) (raw)
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Nanotechnology Reviews
In this study, three-dimensional (3D) printing of 3D scaffolds containing halloysite nanotubes (HNTs) and strontium ranelate (SrR) as a carrier for the promotion of bone regeneration is investigated. SrR acts as an anabolic bone-forming and anti-catabolic agent, while HNTs act as a carrier of SrR. Poly(lactic acid) (PLA) is used as a biodegradable matrix and carrier for HNTs and SrR. The effects of the SrR addition on the morphological, biological, and in vitro release properties of the scaffolds are evaluated. The morphological results show a homogeneous structure with a proper pore size (approximately 400 µm) suitable for osteogenesis. The contact angle is decreased after the addition of SrR to the scaffold to 67.99°, suitable for cell attachment. X-ray diffraction shows that the SrR is homogenously and molecularly distributed in the PLA matrix and reduces the crystallinity in the prepared scaffolds. The in vitro release results demonstrate that the release profile of the SrR is s...
ACS Biomaterials Science & Engineering, 2015
Strontium was shown to enhance bone growth; however, its oral administration may lead to severe side effects. The application of strontium in orthopedic biomaterials may therefore be an alternative to achieve targeted and sustained strontium treatment to the surgery site in aid of bone growth locally. In this study, strontium-containing composites were prepared by introducing various levels of strontium into amorphous apatite and extruding the obtained apatite powders into polylactide in a weight ratio of 1:1. Strontium substitution increased apatite dissolution and enhanced the degradation behavior of the resulting composites. Sustained and dose-dependent strontium release from the composites was observed for up to 24 weeks in simulated physiological solution, indicating that strontium release can be tuned by its substitution level in the embedded apatite. Strontium-containing composites enhanced the osteogenic differentiation of murine mesenchymal stromal cells in vitro in a dose-dependent fashion. After heterotopic implantation with the combination of rhBMP-2, bone formation on strontiumcontaining composites was enhanced. These results suggest that strontium-releasing composites provide a local ion-rich (i.e., Sr 2+ as well as Ca 2+ and PO 4 3− ) environment that favors osteogenic differentiation and in vivo bone formation.
Applied Sciences
Strontium (Sr) and Magnesium (Mg) are bioactive ions that have been proven to exert a beneficial effect on bone; therefore, their incorporation into bone substitutes has long been viewed as a possible approach to improve tissue integration. However, the thermal instability of Mg-substituted hydroxyapatites has hitherto limited development. We previously described the creation of thermally consolidated porous constructs of Mg,Sr co-substituted apatites with adequate mechanical properties for their clinical use. The present paper describes the biocompatibility of Mg,Sr co-substituted granules using an alveolar-bone-derived primary model of human osteoblasts. Cells were cultured in the presence of different amounts of hydroxyapatite (HA), Sr-substituted HA, or MgSrHA porous macrogranules (with a size of 400–600 microns, obtained by grinding and sieving the sintered scaffolds) for three and seven days, and their viability was measured by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetraz...
Biomimetic PLGA/Strontium-Zinc Nano Hydroxyapatite Composite Scaffolds for Bone Regeneration
Journal of Functional Biomaterials, 2022
Synthetic bone graft substitutes have attracted increasing attention in tissue engineering. This study aimed to fabricate a novel, bioactive, porous scaffold that can be used as a bone substitute. Strontium and zinc doped nano-hydroxyapatite (Sr/Zn n-HAp) were synthesized by a water-based sol-gel technique. Sr/Zn n-HAp and poly (lactide-co-glycolide) (PLGA) were used to fabricate composite scaffolds by supercritical carbon dioxide technique. FTIR, XRD, TEM, SEM, and TGA were used to characterize Sr/Zn n-HAp and the composite scaffolds. The synthesized scaffolds were adequately porous with an average pore size range between 189 to 406 µm. The scaffolds demonstrated bioactive behavior by forming crystals when immersed in the simulated body fluid. The scaffolds after immersing in Tris/HCl buffer increased the pH value of the medium, establishing their favorable biodegradable behavior. ICP-MS study for the scaffolds detected the presence of Sr, Ca, and Zn ions in the SBF within the firs...
Polymer Bulletin
Based on a self-assembly mechanism, a co-precipitation method was utilized to fabricate bone-like biomimetic nanocomposite with a simplifi ed preparation approach and accessible materials to investigate in depth some characteristics of hydroxyapatite/collagen(HAp/Col) nanocomposite for the elucidation of performances in some respects. The as-prepared composite was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transformation infrared spectroscopy, and thermal analysis. The results show that HAp nanocrystals formed as preferentially oriented slender needles 50-100 nm in length on a felt-like Col matrix which is composed of large numbers of randomly oriented Col fi bers and showed polycrystalline behavior. The as-prepared cellular composites are analogous in both composition and nanostructured architecture to native bone, longer aging time promotes the growth and purifi cation of nano-HAp on Col, and characterization confi rms that chemical interaction occurs and causes intimate bonding between HAp and Col.
Journal of Tissue Engineering and Regenerative Medicine, 2014
In this work, we focus on the in vitro and in vivo response of composite scaffolds obtained by incorporating Mg,CO 3-doped hydroxyapatite (HA) particles in poly(«-caprolactone) (PCL) porous matrices. After a complete analysis of chemical and physical properties of synthesized particles (i.e. SEM/EDS, DSC, XRD and FTIR), we demonstrate that the Mg,CO 3 doping influences the surface wettability with implications upon cell-material interaction and new bone formation mechanisms. In particular, ion substitution in apatite crystals positively influences the early in vitro cellular response of human mesenchymal stem cells (hMSCs), i.e. adhesion and proliferation, and promotes an extensive mineralization of the scaffold in osteogenic medium, thus conforming to a more faithful reproduction of the native bone environment than undoped HA particles, used as control in PCL matrices. Furthermore, we demonstrate that Mg,CO 3-doped HA in PCL scaffolds support the in vivo cellular response by inducing neo-bone formation as early as 2 months post-implantation, and abundant mature bone tissue at the sixth month, with a lamellar structure and completely formed bone marrow. Together, these results indicate that Mg 2+ and CO 3 2ion substitution in HA particles enhances the scaffold properties, providing the right chemical signals to combine with morphological requirements (i.e. pore size, shape and interconnectivity) to drive osteogenic response in scaffold-aided bone regeneration.
To develop biodegradable Mg-based metal ceramic composites as bone implant material
Bulletin of Materials Science, 2020
Biodegradable materials for orthopaedic implants have gained much attention due to their similar properties to natural bone. Magnesium-based alloys are considered the best biodegradable material for bone substitute materials. However, magnesium alloys have very high corrosion rate. Research has been focused to fabricate and to make their composites to control their corrosion rates in human physiological environment and to develop the ability of forming bone-like apatite layer on their surface. In the present study, Mg-Zn-Mn metal alloys were selected for making their composites with hydroxyapatite (HAp) and bio-glasses. HAp was prepared by the co-precipitation method and bio-glasses (45S5P7) were prepared by the melting and quenching method. Samples from metal-ceramic composites were prepared by the powder metallurgy route in various compositions. Furthermore, samples were characterized for their phases, microstructure, corrosion behaviour, mechanical properties and bioactivity. The composites showed bioactivity in simulated body fluid (SBF) solution and their young's modulus values were obtained near to the human bone. The degradation properties, as studied in SBF solution, revealed Mg-based alloy composites having approximately 10% bio-active glasses and 10% b-tri-calcium phosphate resulted in the reduction of the corrosion rate.
Biodegradable Ceramics Consisting of Hydroxyapatite for Orthopaedic Implants
Coatings
This study aims to analyze hydroxyapatite (HAP) coatings enriched with Mg and Ti prepared by a magnetron sputtering technique on Ti6Al4V substrate. For preparation of the coatings, three magnetron targets (HAP, MgO and TiO 2) were simultaneously co-worked. The concentration of Mg added was varied by modifying the power applied to the MgO target. In all coatings, the Ti concentration was maintained constant by keeping the same cathode power fed during the whole deposition. The influence of different Mg dopant contents on the formation of phase, microstructure and morphology of the obtained Ti-doped HAP coatings were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Moreover, the effects of Mg addition upon corrosion, mechanical and biological properties were also investigated. Mg-and Ti-doped HAP coating obtained at low radio-frequency (RF) power fed to the MgO target provided material with high corrosion resistance compared to other coatings and bare alloy. A slight decrease in hardness of the coatings was found after the Mg addition, from 8.8 to 5.7 GPa. Also, the values of elastic modulus were decreased from 87 to 53 GPa, this being an advantage for biomedical applications. The coatings with low Mg concentration proved to have good deformation to yielding and higher plastic properties. Biological test results showed that the novel surfaces exhibited excellent properties for the adhesion and growth of bone cells. Moreover, early adherent vital cell numbers were significantly higher on both coatings compared to Ti6Al4V, suggesting that Mg ions may accelerate initial osteoblast adhesion and proliferation.
Materials Science and Engineering: C, 2014
The present work investigates the preparation of biomimetic nanocrystalline apatites co-substituted with Mg, CO 3 and Sr to be used as starting materials for the development of nanostructured bio-devices for regeneration of osteoporotic bone. Biological-like amounts of Mg and CO 3 ions were inserted in the apatite structure to mimic the composition of bone apatite, whereas the addition of increasing quantities of Sr ions, from 0 up to 12 wt.%, as anti-osteoporotic agent, was evaluated. The chemical-physical features, the morphology, the degradation rates, the ion release kinetics as well as the in vitro bioactivity of the as-prepared apatites were fully evaluated. The results indicated that the incorporation of 12 wt.% of Sr can be viewed as a threshold for the structural stability of Mg-CO 3 -apatite. Indeed, incorporation of lower quantity of Sr did not induce considerable variations in the chemical structure of Mg-CO 3 -apatite, while when the Sr doping extent reached 12 wt.%, a dramatically destabilizing effect was detected on the crystal structure thus yielding alteration of the symmetry and distortion of the PO 4 . As a consequence, this apatite exhibited the fastest degradation kinetic and the highest amount of Sr ions released when tested in physiological conditions. In this respect, the surface crystallization of new calcium phosphate phase when immersed in physiological-like solution occurred by different mechanisms and extents due to the different structural chemistry of the variously doped apatites. Nevertheless, all the apatites synthesized in this work exhibited in vitro bioactivity demonstrating their potential use to develop biomedical devices with anti-osteoporotic functionality.