In vitro degradability, bioactivity and cell responses to mesoporous magnesium silicate for the induction of bone regeneration

Accelerated Osteogenic Response of Electrodynamically Stimulated Mg1-xCaxSi1-xZrxO3 (x = 0-0.4) Bioelectrets

MgSiO3-based biodegradable ceramics demonstrated remarkable potential for treating small-scale bone defects and temporary bone replacement. In addition, the dissolution behavior of MgSiO3 bioceramics can be tuned by doping of Ca and Zr elements at Mg and Si sites, respectively. The present study reported the influence of formation of Ca- and Zr-codoped Mg1-xCaxSi1-xZrxO3 (x = 0, 0.1, 0.2, 0.3, and 0.4) bioelectrets and electrodynamic stimulation toward improving their osteogenic response. Mg1-xCaxSi1-xZrxO3 electrets were successfully synthesized by a solid-state route. A detailed X-ray photoelectron spectroscopy (XPS) analyses revealed that the electrets produced oxygen-deficient active sites. The formation of Mg1-xCaxSi1-xZrxO3 electrets significantly increased the surface hydrophilicity. Inductively coupled plasma (ICP) analyses were used to examine the leaching behavior of Ca/Zr-codoped MgSiO3 bioceramics. In vitro cell culture analyses indicated that the osteogenesis of MG-63 cells was remarkably enhanced on the electrodynamic field-treated Mg1-xCaxSi1-xZrxO3 bioelectrets as compared to hydroxyapatite (HA). Moreover, a better osteogenic response was observed for higher concentrations of Ca (0.3 and 0.4) and Zr (0.3 and 0.4) doping in the MgSiO3 bioelectrets. Further, the mechanism of enhanced cellular functionality was revealed by the measurement of intracellular Ca2+.

The Influence of Nanosilica on Properties of Cement Based on Tetracalcium Phosphate/Monetite Mixture with Addition of Magnesium Pyrophoshate

The effect of nanosilica on the microstructure setting process of tetracalcium phosphate/nanomonetite calcium phosphate cement mixture (CPC) with the addition of 5 wt% of magnesium pyrophosphate (assigned as CT5MP) and osteogenic differentiation of mesenchymal stem cells cultured in cement extracts were studied. A more compact microstructure was observed in CT5MP cement with 0.5 wt% addition of nanosilica (CT5MP1Si) due to the synergistic effect of Mg₂P₂O₇ particles, which strengthened the cement matrix and nanosilica, which supported gradual growth and recrystallization of HAP particles to form compact agglomerates. The addition of 0.5 wt% of nanosilica to CT5MP cement caused an increase in CS from 18 to 24 MPa while the setting time increased almost twofold. It was verified that adding nanosilica to CPC cement, even in a low amount (0.5 and 1 wt% of nanosilica), positively affected the injectability of cement pastes and differentiation of cells with upregulation of osteogenic markers in cells cultured in cement extracts. Results revealed appropriate properties of these types of cement for filling bone defects.

Advances in Regenerative Sports Medicine Research

Regenerative sports medicine aims to address sports and aging-related conditions in the locomotor system using techniques that induce tissue regeneration. It also involves the treatment of meniscus and ligament injuries in the knee, Achilles’ tendon ruptures, rotator cuff tears, and cartilage and bone defects in various joints, as well as the regeneration of tendon–bone and cartilage–bone interfaces. There has been considerable progress in this field in recent years, resulting in promising steps toward the development of improved treatments as well as the identification of conundrums that require further targeted research. In this review the regeneration techniques currently considered optimal for each area of regenerative sports medicine have been reviewed and the time required for feasible clinical translation has been assessed. This review also provides insights into the direction of future efforts to minimize the gap between basic research and clinical applications.

Mesoporous Biodegradable Magnesium Phosphate-Citrate Nanocarriers Amplify Methotrexate Anticancer Activity in HeLa Cells

We present the synthesis of amorphous, mesoporous, colloidal magnesium phosphate-citrate nanoparticles (MPCs) from biogenic precursors, resulting in a biocompatible and biodegradable nanocarrier that amplifies the action of the anticancer drug methotrexate (MTX). Synthesis conditions were gradually tuned to investigate the influence of the chelating agent citric acid on the colloidal stability and the mesoporosity of the obtained nanoparticles. With optimized synthesis conditions, a large BET surface area of 560 m²/g was achieved. We demonstrate the potential of these biocompatible and biodegradable mesoporous MPCs as a drug delivery system. Lipid-coated MPCs were used to load the fluorescent dye calcein and the chemotherapeutic agent MTX into the mesopores. In vitro experiments show very low premature release of the cargo but efficient stimuli-responsive release in an environment of pH 5.5, in which MPCs degrade. Lipid-coated MPCs are taken up by cancer cells and are nontoxic up to concentrations of 100 μg/mL. When loaded with MTX serving as a representative model drug for in vitro studies, MPCs induced efficient cell death with an IC₅₀ value of 1.1 μg/mL. Compared to free MTX, its delivery with MPCs enhances its efficiency by an order of magnitude. In summary, we have developed a biodegradable nanomaterial synthesized from biocompatible precursors that are neither toxic by themselves nor in the form of nanoparticles. With these features, MPCs may be applied as drug delivery systems and have the potential to reduce the side effects of current chemotherapies.

Characterization of magnesium doped sol-gel biomaterial for bone tissue regeneration: The effect of Mg ion in protein adsorption

Magnesium is the fourth most abundant element in the human body with a wide battery of functions in the maintenance of normal cell homeostasis. In the bone, this element incorporates in the hydroxyapatite structure and it takes part in mineral metabolism and regulates osteoclast functions. In this study, sol-gel materials with increasing concentrations of MgCl₂ (0.5, 1, and 1.5%) were synthesized and applied onto Ti surfaces as coatings. The materials were first physicochemically characterized. In vitro responses were examined using the MC3T3-E1 osteoblastic cells and RAW264.7 macrophages. Human serum protein adsorption was evaluated employing nLC-MS/MS. The incorporation of Mg did not affect the crosslinking of the sol-gel network, and a controlled release of Mg was observed; it was not cytotoxic at any of the tested concentrations. The cytoskeleton arrangement of MC3T3-E1 cells cultured on the Mg-doped materials changed in comparison with controls; the cells became more elongated, with protruded lamellipodia and increased cell surface. The expression of integrins (ITGA5 and ITGB1) was boosted by Mg-coatings. The ALP activity and expression of TGF-β, OSX and RUNX2 genes were also increased. In RAW264.7 cells, TNF-α secretion was reduced, while TGF-β and IL-4 expression rose. These changes correlated with the altered protein adsorption patterns. The Mg-doped coatings showed increased adsorption of anti-inflammatory (CLUS, IC1, CFAH, and VTNC), cell adhesion (DSG1, FILA2, and DESP) and tissue regeneration (VTNC and CYTA) proteins. This integrated approach to biomaterial characterization revealed the potential of Mg in bone tissue regeneration.

Additive manufacturing pertaining to bone: Hopes, reality and future challenges for clinical applications

For the past 20 years, the democratization of additive manufacturing (AM) technologies has made many of us dream of: low cost, waste-free, and on-demand production of functional parts; fully customized tools; designs limited by imagination only, etc. As every patient is unique, the potential of AM for the medical field is thought to be considerable: AM would allow the division of dedicated patient-specific healthcare solutions entirely adapted to the patients' clinical needs. Pertinently, this review offers an extensive overview of bone-related clinical applications of AM and ongoing research trends, from 3D anatomical models for patient and student education to ephemeral structures supporting and promoting bone regeneration. Today, AM has undoubtably improved patient care and should facilitate many more improvements in the near future. However, despite extensive research, AM-based strategies for bone regeneration remain the only bone-related field without compelling clinical proof of concept to date. This may be due to a lack of understanding of the biological mechanisms guiding and promoting bone formation and due to the traditional top-down strategies devised to solve clinical issues. Indeed, the integrated holistic approach recommended for the design of regenerative systems (i.e., fixation systems and scaffolds) has remained at the conceptual state. Challenged by these issues, a slower but incremental research dynamic has occurred for the last few years, and recent progress suggests notable improvement in the years to come, with in view the development of safe, robust and standardized patient-specific clinical solutions for the regeneration of large bone defects.

Biological evaluation of the modified nano-amorphous phosphate calcium doped with citrate/poly-amino acid composite as a potential candidate for bone repair and reconstruction

Large numbers of research works related to fabricating organic-inorganic composite materials have been carried out to mimic the natural structure of bone. In this study, a new modified n-ACP doped with citrate (n-ACP-cit)/poly (amino acids) (PAA) composite (n-ACP-cit/PAA) was synthesized by employing high bioactive n-ACP-cit and the biodegradable and biocompatible PAA copolymer. Its basic structure was characterized by X-ray diffraction spectroscopy, Fourier transformed infrared spectroscopy, and X-ray photoelectron spectroscopy. Moreover, the degradability, bioactivity, biocompatibility, and osteoconductivity of n-ACP-cit/PAA composite were evaluated in vitro and in vivo, using simulated body fluid (SBF) solution soaking test, mouse bone marrow mesenchymal stem cells proliferation and differentiation, morphological observation test, expression of genes associated with osteogenesis, and bone defect model repair test, respectively. The modified n-ACP-cit/PAA composite exhibited a much higher weight loss rate (36.01 wt.%) than that of PAA (23.99 wt.%) after immersing in SBF solution for 16 weeks and the pH values of local environment restored to neutral condition. Moreover, cells co-culturing with composites exhibited higher alkaline phosphatase activity, more calcium nodule-formation, and higher expression levels of osteogenic differentiation-related genes (Bmp-2, Colla I, OCN, OPN, and Runx-2) than that of PAA. Furthermore, the bone defect model repair test revealed that the composite could be intimately incorporated with the surrounding bone without causing any deleterious reaction and capable of guiding new bone formation. Together, these results indicated that the new modified bone repair n-ACP-cit/PAA composite material with specific characteristics may be designed for meeting diverse requirements from biomedical applications.

Effects of degradable magnesium on paracrine signaling between human umbilical cord perivascular cells and peripheral blood mononuclear cells

Human mesenchymal stem cells (MSC) interact with numerous immune cells that can promote regenerative processes and inhibit inflammatory responses. We hypothesised that the cross-talk between human umbilical cord perivascular cells (HUCPV; an alternative source of MSC) and peripheral blood mononuclear cells (PBMC) could be influenced by degradable transwell magnesium (Mg). To study the correlations between paracrine signaling and specific cellular behaviour during the host response to Mg, we used a transwell coculture system for up to 7 days. The proliferation and viability of both cell types were not significantly influenced by Mg. When HUCPV were cultured with degradable Mg, a moderate inflammation (e.g., lower secretions of pro-inflammatory interleukin 1 beta and IL2, and tumour necrosis factor alpha, interferon gamma, anti-inflammatory interleukins 4, 5, 10, 13, and 1 receptor antagonists and granulocyte colony stimulating factor), and an increased pro-healing M2 macrophage phenotype were observed. Moreover, when PBMC were cultured with degradable Mg, the expression of migration/wound healing related cytokines (interleukin 8, granulocyte-macrophage colony-stimulating factor, monocyte chemoattractant protein 1 and macrophage inflammatory protein 1α/β) was upregulated, accompanied by an increase in the migration ability of HUCPV (cell scratch assay). In addition, an increased pro-osteogenic potential was demonstrated via an increase of osteoblastic markers (e.g., alkaline phosphatase activity, specific gene expression and cytokine release). These results collectively imply that Mg possesses osteo-immunomodulatory properties. They also help to design Mg-based bone substitute biomaterials capable of exhibiting desired immune reactions and good clinical performance.

Biological evaluation of bone substitute

Critical-sized defects (CSDs) caused by trauma, tumor resection, or skeletal abnormalities create a high demand for bone repair materials (BRMs). Over the years, scientists have been trying to develop BRMs and evaluate their efficacy using numerous developed methods. BRMs are characterized by osteogenesis and angiogenesis promoting properties, the latter of which has rarely been studied in vitro and in vivo. While blood vessels are required to provide nutrients. Bone mass maintains a dynamic balance under the joint action of osteolytic and osteogenic activity in which monocytes differentiate into osteolytic cells, and osteoprogenitor cells differentiate into osteogenic cells. This review would be helpful for inexperienced researchers as well as present a comprehensive overview of methods used to investigate the effect of BRMs on osteogenic cells, osteolytic cells, and blood vessels, as well as their biocompatibility and biological performance. This review is expected to facilitate further research and development of new BRMs.

Macro-Microporous Surface with Sulfonic Acid Groups and Micro-Nano Structures of PEEK/Nano Magnesium Silicate Composite Exhibiting Antibacterial Activity and Inducing Cell Responses

Purpose

To improve the surface bio-properties of polyetheretherketone (PEEK)/nano magnesium silicate (n-MS) composite (PC).

Materials and Methods

The surface of PC was firstly treated by particle impact (PCP) and subsequently modified by concentrated sulfuric acid (PCPS).

Results

PCPS surface exhibited not only macropores with sizes of about 150 μm (fabricated by particle impact) but also micropores with sizes of about 2 μm (created by sulfonation of PEEK) on the macroporous walls, and sulfonic acid (-SO₃H) groups were introduced on PCPS surface. In addition, many n-MS nanoparticles were exposed on the microporous walls, which formed micro-nano structures. Moreover, the surface roughness and hydrophilicity of PCPS were obviously enhanced as compared with PC and PCP. Moreover, the apatite mineralization of PCPS in simulated body fluid (SBF) was obviously improved as compared with PC. Furthermore, compared with PC and PCP, PCPS exhibited antibacterial performances due to the presence of -SO₃H groups. In addition, the responses (eg, adhesion and proliferation as well as differentiation) of bone marrow mesenchymal stem cell of rat to PCPS were significantly promoted as compared with PC and PCP.

Conclusion

PCPS with macro-microporous surface containing -SO₃H groups and micro-nano structures exhibited antibacterial activity and induced cell responses, which might possess large potential for bone substitute and repair.

Hierarchical porous Mg2SiO4-CoFe2O4 nanomagnetic scaffold for bone cancer therapy and regeneration: Surface modification and in vitro studies

3D multifunctional bone scaffolds have recently attracted more attention in bone tissue engineering because of addressing critical issues like bone cancer and inflammation beside bone regeneration. In this study, a 3D bone scaffold is fabricated from Mg₂SiO₄-CoFe₂O₄ nanocomposite which is synthesized via a two-step synthesis strategy and then the scaffold's surface is modified with poly-3-hydroxybutyrate (P3HB)-ordered mesoporous magnesium silicate (OMMS) composite to improve its physicochemical and biological properties. The Mg₂SiO₄-CoFe₂O₄ scaffold is fabricated through polymer sponge technique and the scaffold exhibits an interconnected porous structure in the range of 100-600 μm. The scaffold is then coated with OMMS/P3HB composite via dip coating and the physical, chemical, and biological-related properties of OMMS/P3HB composite-coated scaffold are assessed and compared to the non-coated and P3HB-coated scaffolds in vitro. It is found that, on the one hand, P3HB increases the cell attachment, proliferation, and compressive strength of the scaffold, but on the other hand, it weakens the bioactivity kinetic. Addition of OMMS to the coating composition is accompanied with significant increase in bioactivity kinetic. Besides, OMMS/P3HB composite-coated scaffold exhibits higher drug loading capacity and more controlled release manner up to 240 h than the other samples because of OMMS which has a high surface area and ordered mesoporous structure suitable for controlled release applications. The overall results indicate that OMMS/P3HB coating on Mg₂SiO₄-CoFe₂O₄ scaffold leads to a great improvement in bioactivity, drug delivery potential, compressive strength, cell viability, and proliferation. Moreover, OMMS/P3HB composite-coated scaffold has heat generation capability for hyperthermia-based bone cancer therapy and so it is suggested as a multifunctional scaffold with great potentials for bone cancer therapy and regeneration.

Injectable PLGA microspheres with tunable magnesium ion release for promoting bone regeneration

Magnesium ions (Mg²⁺) are bioactive and proven to promote bone tissue regeneration, in which the enhancement efficiency is closely related to Mg²⁺ concentrations. Currently, there are no well-established bone tissue engineering scaffolds that can precisely control Mg²⁺ release, although this capability could have a marked impact in bone regeneration. Leveraging the power of biodegradable microspheres to control the release of bioactive factors, we developed lactone-based biodegradable microspheres that served as both injectable scaffolds and Mg²⁺ release system for bone regeneration. The biodegradable microsphere (PMg) was prepared from poly(lactide-co-glycolide) (PLGA) microspheres co-embedded with MgO and MgCO₃ at a fixed total loading amount (20 wt%) with different weight ratios (1:0; 3:1; 1:1; 1:3; 0:1). The PMg microspheres demonstrated controlled release of Mg²⁺ by tuning the MgO/MgCO₃ ratios. Specifically, faster release with higher initial concentrations of Mg²⁺ were detected at higher MgO fractions, while long-term sustained release with lower concentrations of Mg²⁺ was obtained at higher MgCO₃ fractions. All prepared PMg microspheres were non-cytotoxic. Furthermore, they promoted attachment, proliferation, osteogenic differentiation, especially, cell migration of bone marrow mesenchymal stromal cells (BMSCs). Among these microspheres, PMg-III microspheres (MgO/MgCO₃ in 1:1) exhibited the strongest promotion of mineral depositions and osteogenic differentiation of BMSCs. PMg-III microspheres were injected into the critical-sized calvarial defect of a rat model, resulting in significant bone regeneration when compared to the control group filled with PLGA microspheres. In the PMg-III group, the new bone volume fraction (BV/TV) and bone mineral density (BMD) reached 32.9 ± 5.6% and 325.7 ± 20.2 mg/cm³, respectively, which were much higher than the values 8.1 ± 2.5% (BV/TV) and 124 ± 35.8 mg/cm³ (BMD) in the PLGA group. These findings indicated that bioresorbable microspheres possessing controlled Mg²⁺ release features were efficient in treating bone defects and promising for future in vivo applications. STATEMENT OF SIGNIFICANCE: Magnesium plays pivotal roles in regulating osteogenesis, which exhibits concentration-dependent behaviors. However, no generally accepted controlled-release system is reported to correlate Mg²⁺ concentration with efficient bone regeneration. Biodegradable microspheres with injectability are excellent cell carriers for tissue engineering, moreover, good delivery systems for bioactive factors. By co-embedding magnesium compounds (MgO, MgCO₃) with different dissolution rates in various ratios, tunable release of Mg²⁺ from the microspheres was readily achieved. Accordingly, significant promotion in bone defect regeneration is achieved with microspheres displaying proper sustained release of Mg²⁺. The developed strategy may serve as valuable guidelines for bone tissue engineering scaffold design, which allows precise control on the release of bioactive metal ions like Mg²⁺ toward potential clinical translation.

Electrophoretically deposited mesoporous magnesium silicate with ordered nanopores as an antibiotic-loaded coating on surface-modified titanium

Infection is quite usual for implants after surgery and a systemic administration of antibiotics causes problems before the eradication of bacteria. Localized drug delivery from implants is an effective way by which the mentioned target can be met. In the current work, ordered mesoporous magnesium silicate (OMMS) is coated on plasma electrolytic oxidation (PEO)-modified titanium (Ti) substrate through electrophoretic deposition (EPD) and rifampin as an antibiotic is loaded on OMMS coating to be applied as an antibacterial coating. The immersion test into simulated body fluid and also potentiodynamic polarization assay are adopted to assess the in vitro bioactivity up to 7 days and corrosion resistance of the specimens, respectively. The double surface coatings of PEO and EPD are achieved on Ti substrate and the thickness for each one is found to be 4 and 25 μm, respectively. Regarding to drug delivery capability of OMMS as the EPD coating, the loading capacity is 25% and release trend sustains up to 96 h. The antibacterial activity and also cell viability of OMMS coating are significantly increased with rifampin loading. The results of our study exhibit that OMMS as a multifunctional coating deposited on the PEO-modified Ti substrate improves corrosion resistance, in vitro bioactivity, alkaline phosphatase activity, and mineralization of the substrate. Moreover, rifampin-loaded OMMS coating is not only able to prevent infection, but it also increases the osteogenesis cells viability. Therefore, rifampin-loaded OMMS coating on Ti is potentially regarded appropriate for orthopedic applications.

Biodegradable AIEgen-functionalised mesoporous bioactive glass nanoparticles for drug delivery and cell imaging

AIEgen-functionalised mesoporous bioactive glass nanospheres with excellent degradability in an acid environment show potential application in drug delivery and cell imaging.

Nanoporosity improved water absorption, in vitro degradability, mineralization, osteoblast responses and drug release of poly(butylene succinate)-based composite scaffolds containing nanoporous magnesium silicate compared with magnesium silicate

Bioactive composite macroporous scaffold containing nanoporosity was prepared by incorporation of nanoporous magnesium silicate (NMS) into poly(butylene succinate) (PBSu) using solvent casting-particulate leaching method. The results showed that the water absorption and in vitro degradability of NMS/PBSu composite (NMPC) scaffold significantly improved compared with magnesium silicate (MS)/PBSu composite (MPC) scaffold. In addition, the NMPC scaffold showed improved apatite mineralization ability, indicating better bioactivity, as the NMPC containing nanoporosity could induce more apatite and homogeneous apatite layer on the surfaces than MPC scaffold. The attachment and proliferation of MC3T3-E1 cells on NMPC scaffold increased significantly compared with MPC scaffold, and the alkaline phosphatase (ALP) activity of the cells on NMPC scaffold was expressed at considerably higher levels compared with MPC scaffold. Moreover, NMPC scaffold with nanoporosity not only had large drug loading (vancomycin) but also exhibited drug sustained release. The results suggested that the incorporation of NMS into PBSu could produce bioactive composite scaffold with nanoporosity, which could enhance water absorption, degradability, apatite mineralization and drug sustained release and promote cell responses.

Nanomaterial-based bone regeneration

Bone diseases/injuries have been driving an urgent quest for bone substitutes for bone regeneration. Nanoscaled materials with bone-mimicking characteristics may create suitable microenvironments to guide effective bone regeneration. In this review, the natural hierarchical architecture of bone and its regeneration mechanisms are elucidated. Recent progress in the development of nanomaterials which can promote bone regeneration through bone-healing mimicry (e.g., compositional, nanocrystal formation, structural, and growth factor-related mimicking) is summarized. The nanoeffects of nanomaterials on the regulation of bone-related biological functions are highlighted. How to prepare nanomaterials with combinative bone-biomimicry features according to the bone healing process is prospected in order to achieve rapid bone regeneration in situ.

The Horizon of Materiobiology: A Perspective on Material-Guided Cell Behaviors and Tissue Engineering

Although the biological functions of cell and tissue can be regulated by biochemical factors (e.g., growth factors, hormones), the biophysical effects of materials on the regulation of biological activity are receiving more attention. In this Review, we systematically summarize the recent progress on how biomaterials with controllable properties (e.g., compositional/degradable dynamics, mechanical properties, 2D topography, and 3D geometry) can regulate cell behaviors (e.g., cell adhesion, spreading, proliferation, cell alignment, and the differentiation or self-maintenance of stem cells) and tissue/organ functions. How the biophysical features of materials influence tissue/organ regeneration have been elucidated. Current challenges and a perspective on the development of novel materials that can modulate specific biological functions are discussed. The interdependent relationship between biomaterials and biology leads us to propose the concept of "materiobiology", which is a scientific discipline that studies the biological effects of the properties of biomaterials on biological functions at cell, tissue, organ, and the whole organism levels. This Review highlights that it is more important to develop ECM-mimicking biomaterials having a self-regenerative capacity to stimulate tissue regeneration, instead of attempting to recreate the complexity of living tissues or tissue constructs ex vivo. The principles of materiobiology may benefit the development of novel biomaterials providing combinative bioactive cues to activate the migration of stem cells from endogenous reservoirs (i.e., cell niches), stimulate robust and scalable self-healing mechanisms, and unlock the body's innate powers of regeneration.

Promotion of in vivo degradability, vascularization and osteogenesis of calcium sulfate-based bone cements containing nanoporous lithium doping magnesium silicate

Nanoporous lithium doping magnesium silicate (nl-MS) was introduced into calcium sulfate hemihydrate to prepare calcium sulfate composite (nl-MSC) bone cements. The introduction of nl-MS improved the in vitro degradability of nl-MSC cements, which could neutralize acidic degradable products of calcium sulfate and prevented the pH from dropping. The cements were implanted into the bone defects of femur bone of rabbits, and the results of histological and immunohistochemical analysis revealed that massive new bone tissue formed in the defects while the cements were degradable, indicating that the osteogenesis and degradability of the nl-MSC cements were much better than the control calcium sulfate dihydrate (CSD) cements. Furthermore, the positive expression of vascular endothelial growth factor and collagen type I for nl-MSC cements was higher than CSD, indicating that addition of nl-MS into the cements enhanced vascularization and osteogenic differentiation. The results suggested that the nl-MSC cements with good biocompatibility and degradability could promote vascularization and osteogenesis, and had great potential to treat bone defects.

Effects of mesoporous calcium magnesium silicate on setting time, compressive strength, apatite formation, degradability and cell behavior to magnesium phosphate based bone cements

Mesoporous calcium magnesium silicate was doped into magnesium phosphate to fabricate magnesium phosphate based composite cements (MBC).

Degradability, cytocompatibility, and osteogenesis of porous scaffolds of nanobredigite and PCL-PEG-PCL composite

Biocomposite scaffolds were fabricated by incorporation of nanobredigite (n-BD) into the polymer of poly(ε-caprolactone)-poly(ethyleneglycol)-poly(ε-caprolactone) (PCL-PEG-PCL). The results revealed that the addition of n-BD into PCL-PEG-PCL significantly improved water absorption, compressive strength, and degradability of the scaffolds of n-BD/PCL-PEG-PCL composite (n-BPC) compared with PCL-PEG-PCL scaffolds alone. In addition, the proliferation and alkaline phosphatase activity of MG63 cells cultured on n-BPC scaffolds were obviously higher than that cultured on PCL-PEG-PCL scaffolds. Moreover, the results of the histological evaluation from the animal model revealed that the n-BPC scaffolds significantly improved new bone formation compared with the PCL-PEG-PCL scaffolds, indicating good osteogenesis. The n-BPC scaffolds with good biocompatibility could stimulate cell proliferation, differentiation, and bone tissue regeneration and would be an excellent candidate for bone defect repair.

Fabrication and characterization of poly(vinyl alcohol)-TiO2 nanocomposite films for orthopedic applications

Poly(vinyl alcohol) (PVA) is reinforced with TiO2 nanoparticles in order to enhance thermo-mechanical stabilities, surface characteristics and osteoblastic cell adhesion. PVA-TiO2 nanocomposite films with desirable mechanical, thermal and biocompatible properties are fabricated through solution casting method followed by de-hydrothermal cross-linking treatment. The composition of TiO2 nanoparticles was standardized to achieve mechanically stable nanocomposite films, based on tensile strength measurements composition of TiO2 is determined as optimal at 3wt%. PVA-TiO2 nanocomposite films were characterized by Scanning electron microscopy, Energy dispersive spectroscopy, Atomic force microscopy, Ultra violet and Fourier transform infrared spectroscopic techniques. Elemental mapping studies substantiate incorporation of TiO2 nanoparticles within the PVA matrix. Dimensional stability evaluated by soaking films in SBF for 24h insinuates the role of TiO2 in the direction of controlling degree of swelling. In-vitro bioactivity test and cell adhesion results also predict that presence of TiO2 is advantageous to enhance apatite growth and promote cell-substrate interaction. SEM studies illustrate improved surface morphology of PVA-TiO2 nanocomposite film with homogenously distributed TiO2 nanoparticles, which help to enhance thermo-mechanical behavior. TiO2 nanoparticles construct cell-adhesive hydrophilic nano-domains that act as potential cell adhesion sites and promotes osteointegration. Bio compatibility studies proved that thermally cross-linked PVA is non-toxic in relation to PVA cross-linked with glutaraldehyde. Cytotoxicity and cell adhesion of nanocomposite films evaluated through cell viability (MMT) assay and crystal violet staining revealed that PVA-3wt% TiO2nanocomposite could act as an excellent composite and hence suitable to be used in bone implant applications.

Influences of mesoporous magnesium silicate on the hydrophilicity, degradability, mineralization and primary cell response to a wheat protein based biocomposite

With the addition of bioactive m-MS,WP40 composite possessed excellent bioactivity and cytocompatibility.

Superparamagnetic yolk–shell porous nanospheres of iron oxide@magnesium silicate: synthesis and application in high-performance anticancer drug delivery

The as-prepared yolk–shell porous nanospheres of SPIO@MS exhibit a high drug loading capacity, and a sustained and pH-responsive drug release behaviour.

Magnesium substituted hydroxyapatite whiskers: synthesis, characterization and bioactivity evaluation

Magnesium (Mg) substituted hydroxyapatite (Mg-HAp) whiskers were hydrothermally synthesized using acetamide as a homogeneous precipitation reagent.

Templated solvothermal synthesis of magnesium silicate hollow nanospheres with ultrahigh specific surface area and their application in high-performance protein adsorption and drug delivery

Magnesium silicate hollow nanospheres with ultrahigh protein/drug loading capacity and high anticancer activity are reported.

Effects of magnesium silicate on the mechanical properties, biocompatibility, bioactivity, degradability, and osteogenesis of poly(butylene succinate)-based composite scaffolds for bone repair

The m-MS/PBSu scaffolds, with a hierarchical porous structure, could promote cell proliferation in vitro and bone regeneration in vivo.

In vitro degradability, bioactivity and primary cell responses to bone cements containing mesoporous magnesium-calcium silicate and calcium sulfate for bone regeneration

Mesoporous calcium sulfate-based bone cements (m-CSBC) were prepared by introducing mesoporous magnesium-calcium silicate (m-MCS) with specific surface area (410.9 m² g(-1)) and pore volume (0.8 cm³ g(-1)) into calcium sulfate hemihydrate (CSH). The setting time of the m-CSBC was longer with the increase of m-MCS content while compressive strength decreased. The degradation ratio of m-CSBC increased from 48.6 w% to 63.5 w% with an increase of m-MCS content after soaking in Tris-HCl solution for 84 days. Moreover, the m-CSBC containing m-MCS showed the ability to neutralize the acidic degradation products of calcium sulfate and prevent the pH from dropping. The apatite could be induced on m-CSBC surfaces after soaking in SBF for 7 days, indicating good bioactivity. The effects of the m-CSBC on vitamin D3 sustained release behaviours were investigated. It was found that the cumulative release ratio of vitamin D3 from the m-CSBC significantly increased with the increase of m-MCS content after soaking in PBS (pH = 7.4) for 25 days. The m-CSBC markedly improved the cell-positive responses, including the attachment, proliferation and differentiation of MC3T3-E1 cells, suggesting good cytocompatibility. Briefly, m-CSBC with good bioactivity, degradability and cytocompatibility might be an excellent biocement for bone regeneration.

Improvement of bioactivity, degradability, and cytocompatibility of biocement by addition of mesoporous magnesium silicate into sodium-magnesium phosphate cement

A novel mesoporous magnesium-based cement (MBC) was fabricated by using the mixed powders of magnesium oxide, sodium dihydrogen phosphate, and mesoporous magnesium silicate (m-MS). The results indicate that the setting time and water absorption of the MBC increased as a function of increasing m-MS content, while compressive strength decreased. In addition, the degradability of the MBC in a solution of Tris-HCl and the ability of apatite formation on the MBC were significantly improved with the increase in m-MS content. In cell culture experiments, the results show that the attachment, proliferation, and alkaline phosphatase activity of the MC3T3-E1 cells on the MBC were significantly enhanced with the increase of the content of m-MS. It can be suggested that the MBC with good cytocompatibility could promote the proliferation and differentiation of the MC3T3-E1 cells. In short, our findings indicate that the MBC containing m-MS had promising potential as a new biocement for bone regeneration and repair applications.

Silica-based mesoporous nanobiomaterials as promoter of bone regeneration process

Silica-based mesostructured nanomaterials have emerged as a full family of biomaterials with tremendous potential to address the requirements for the bone regeneration process. This review focuses on more recent advances in bone regeneration process based on silica-based mesoporous biomaterials during 2012 to January 2015. In this review, we describe application of silica-based mesoporous mesostructured nanomaterials (possessing pore sizes in the range 2-50 nm) for the bone regeneration process. We summarize the preparation methods, the effect of mesopore templates and composition on the mesopore-structure characteristics, and different forms of these materials, including particles, fibers, spheres, scaffolds, and composites. The effect of structural and textural properties of mesoporous materials on the development of new biomaterials for treatment of different bone pathologies such as infection, osteoporosis, cancer, and so forth is discussed. In addition, silica-based mesoporous bioactive glass, as a potential drug/growth factor carrier, is reviewed, which includes the composition-structure-drug delivery relationship and the functional effect on the antibacteria and tissue-stimulation properties. Also, application of different mesoporous materials on construction of 3D macroporous scaffolds for bone tissue engineering was disused. Finally, this review discusses the possibility of covalently grafting different osteoinductive agents to the silica-based mesoporous scaffold surface that act as attracting signals for bone cells to promote the bone regeneration process.

Bone tissue engineering using silica-based mesoporous nanobiomaterials:Recent progress

Bone disorders are of significant concern due to increase in the median age of our population. It is in this context that tissue engineering has been emerging as a valid approach to the current therapies for bone regeneration/substitution. Tissue-engineered bone constructs have the potential to alleviate the demand arising from the shortage of suitable autograft and allograft materials for augmenting bone healing. Silica based mesostructured nanomaterials possessing pore sizes in the range 2-50 nm and surface reactive functionalities have elicited immense interest due to their exciting prospects in bone tissue engineering. In this review we describe application of silica-based mesoporous nanomaterials for bone tissue engineering. We summarize the preparation methods, the effect of mesopore templates and composition on the mesopore-structure characteristics, and different forms of these materials, including particles, fibers, spheres, scaffolds and composites. Also, the effect of structural and textural properties of mesoporous materials on development of new biomaterials for production of bone implants and bone cements was discussed. Also, application of different mesoporous materials on construction of manufacture 3-dimensional scaffolds for bone tissue engineering was discussed. It begins by giving the reader a brief background on tissue engineering, followed by a comprehensive description of all the relevant components of silica-based mesoporous biomaterials on bone tissue engineering, going from materials to scaffolds and from cells to tissue engineering strategies that will lead to "engineered" bone.

Akermanite scaffolds reinforced with boron nitride nanosheets in bone tissue engineering

Akermanite (AKM) is considered to be a promising bioactive material for bone tissue engineering due to the moderate biodegradability and excellent biocompatibility. However, the major disadvantage of AKM is the relatively inadequate fracture toughness, which hinders the further applications. In the study, boron nitride nanosheets (BNNSs) reinforced AKM scaffolds are fabricated by selective laser sintering. The effects of BNNSs on the mechanical properties and microstructure are investigated. The results show that the compressive strength and fracture toughness increase significantly with BNNSs increasing from 0.5 to 1.0 wt%. The remarkable improvement is ascribed to pull out and grain wrapping of BNNSs with AKM matrix. While, overlapping sheets is observed when more BNNSs are added, which results in the decline of mechanical properties. In addition, it is found that the composite scaffolds possess good apatite-formation ability when soaking in simulated body fluids, which have been confirmed by energy dispersed spectroscopy and flourier transform infrared spectroscopy. Moreover, MG63 osteoblast-like cells and human bone marrow stromal cells are seeded on the scaffolds. Scanning electron microscopy analysis confirms that both cells adhere and proliferate well, indicating favorable cytocompatibility. All the facts demonstrate the AKM scaffolds reinforced by BNNSs have potential applications for tissue engineering.

Achieving accelerated osteogenic differentiation via novel magnesium silicate hollow spheres

Novel MgSiO₃ hollow spheres have been rationally designed and applied as promising candidates for osteogenic differentiation in vitro.

Fabrication of nano-structured calcium silicate coatings with enhanced stability, bioactivity and osteogenic and angiogenic activity

The bioactivity and stability of coatings on alloy implants play critical roles in the fast osseointegration and maintenance of a long-term life span of the implants, respectively. Herein, nano-sheet surface on bioactive calcium silicate (CaSiO3, CS) coatings on metal substrates was fabricated by combining atmosphere plasma spraying (APS) and hydrothermal technology (HT). The glassy phase in CS coatings generated by APS was converted into crystalline sheet-like nano-structures after HT treatment. Compared with the original CS coating samples, HT treatment decreased the degradation rate of the CS coatings. Moreover, the fabricated nano-structured topography of CS coatings increased the apatite mineralization ability and significantly enhanced the cell attachment, proliferation, differentiation, alkaline phosphatase (ALP) activity and expression of osteogenic genes and angiogenic factors of rat bone marrow stromal cells (bMSCs). Our results suggest that the nano-structured CS coatings have immense potential in improving the clinical performance of medical implants.