Bioactive Glass Particles Research Articles

Natural Polymers with Bioactive Glass Additives for Bone Regeneration: Chemistry and Trends

Abstract: Natural polymers, such as chitosan (CH) and gelatine (GE), have a wide range of uses in biological environments. This is primarily attributed to their biocompatibility and the body’s recognition of them being as “self” as opposed to “foreign”. These polymers provide a dynamic and cell-friendly interaction environment which is a crucial factor for tissue repair and regeneration. Bone regeneration is a highly intricate multistep process involving a plethora of biomolecules, signalling pathways, and stages in cellular activity. Critically-sized bone defects do not regenerate without an implant due to the cessation of the cellular stimulus associated with new bone formation. Therefore, natural polymers have been combined with bioactive glasses (BGs) to provide a biocompatible delivery matrix and to stimulate bone formation via the release of osteogenic ions from the BG particles. The addition of BG particles in natural polymers has been shown not only to result in an osteogenic response at a cellular level but also result in per se formation of hydroxyapatite (HA) on implant surfaces and regeneration of new bone in vivo. This review discusses the recent trends over the last decade in this field, keeping a focus on the chemistry and properties of CH and GE composites containing a bioactive glass additive.

High-speed photography of gas release from bioactive glass

Bioactive glass has been of interest for applications in bone regeneration. Floating bioactive glass particles were observed to sink in ultrasound. The purpose of this study was to qualify and quantify bubble formation from floating bioactive glass particles. Water droplets containing borosilicate glass 13-93B20 particles, where 20% of the SiO2 was replaced with B2O3, of dimensions <38 μm were subjected to pulsed ultrasound, whilst being video-recorded at high speed. Measured radial expansions >20 μm corresponded to cavitation nuclei of initial radius 0.6 μm. This study provides experimental evidence that gas trapped inside bioactive glass may be released using high-amplitude ultrasound pulses.

Influence of P2O5 addition on glass structure and luminescent properties of Eu3+ ions in SiO2–CaO particles of bioactive glass

Influence of P2O5 addition on glass structure and luminescent properties of Eu3+ ions in SiO2–CaO particles of bioactive glass

In vitro osteogenic and in ovo angiogenic effects of a family of natural origin P2O5-free bioactive glasses.

Bioactive glasses (BGs) belong to a group of ceramic biomaterials having numerous applications due to their excellent biocompatibility and bioactivity. Depending on their composition, properties of BGs can be finely tuned. In this study, we investigated both angiogenic and osteogenic properties of a novel family of BGs from the SiO2-CaO-Na2O system. Three BGs were synthesised from calcite minerals and silica sands extracted from natural deposits. Silica sands used for the synthesis of each glass were obtained from different depths of the deposit, resulting in a different colour and elemental composition. The composition and structural properties of the obtained BGs were determined. Direct culture of human mesenchymal stromal cells (hMSCs) with BG particles at different concentrations was used to investigate the biocompatibility as well as the osteogenic and angiogenic properties of the BGs. In addition, BGs' effect on angiogenesis was further studied in a chick chorioallantoic membrane (CAM) model. Material characterisation confirmed the amorphous character of BGs. Investigated BGs were biocompatible and stimulated early upregulation of RUNX2, ALPL, COL1A1, OCN, and OPN. All BGs tested in a CAM model positively influenced the number, distribution, and branching of the blood vessels. Furthermore, our study revealed that the depth of sand deposit, at which the raw material was collected, had an impact on the osteogenic and angiogenic properties of the resulting glasses. On the one hand, silica sand collected at the deepest layer of the deposit, featuring a higher content of Fe2O3 and Al2O3, originated BGs with potent stimulative capacity of osteogenic and angiogenic gene expression. On the other hand, sand with high silica content and titanium ions resulted in a glass that better supported vessel structure. The BGs presented in this study showed the potential to promote osteogenesis and angiogenesis during bone tissue regeneration, and thus, they will be further studied as part of composite materials for the development of 3D implantable scaffolds.

Antibacterial and In Vitro Bioactivity Studies of Silver-Doped, Cerium-Doped, and Silver–Cerium Co-Doped 80S Mesoporous Bioactive Glass Particles via Spray Pyrolysis

Researchers are concentrating on discovering reducing treatments for bacterial infections due to the worrisome and quick rise of drug-resistant microbial-related illnesses. Metallic ion doping and co-doping mesoporous bioactive glass (MBG) can defend against drug-resistant pathogens of Escherichia coli (E. coli) infection of wounds and solve the issues of bone deformities. In this study, un-doped MBG, silver-doped MBG (Ag-doped MBG), cerium-doped MBG (Ce-doped MBG), and silver–cerium co-doped MBG (Ag-Ce co-doped MBG) have been successfully synthesized via the spray pyrolysis method. In addition, various characterization techniques, including X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and nitrogen adsorption–desorption, were used to investigate the phase compositions, surface morphologies, chemical compositions, inner structure morphologies, chemical bonds/functional groups, and specific surface areas, respectively. The antibacterial efficacy against E. coli was assessed using the colony count technique. All types of MBG with Ag, Ce, and Ag-Ce were effective against E. coli. Furthermore, when immersed in simulated body fluid, the MBGs formed hydroxyapatite and could be used to improve bone defects. Only 5.75 mol% Ag-doped MBG showed toxicity in the MTT assay test. According to our analysis, the 80S-Ag-Ce-MBG was the first Ag-Ce co-doped MBG.

Dissolution of Bioactive Glass S53P4 in Continuous Flows of Tris Buffer and Lactic Acid

In vitro dynamic dissolution of bioactive glass S53P4 particles was studied in a cascade of three reactors. Tris buffer (pH 7.40) and lactic acid (pH 2.00) with flow rates of 0.2 and 0.04 ml/min were fed through the reactors for 24 h. The increased ion concentrations in Tris inflows to the second and third reactors decreased the dissolution of the particles. However, the normalised surface-specific mass loss rate decreased from the first to the third reactor and with decreasing flow rate. No distinct differences were observed in the reaction layers on the particles in the three consecutive reactors. This implied that the ions released in the previous reactors contributed to the reaction layers formed in the following reactors. Highly incongruent dissolution with similar dissolution rates of sodium, calcium, and phosphorus occurred with the two flow rates in lactic acid. Although a thick silica-rich layer formed on the particles, the low pH prevented calcium phosphate layer precipitation. The results imply that S53P4 particles in an implant react at different rates depending on their location but form similar reaction layer morphologies independent of their location in physiological solutions (pH 7.4). On the other hand, S53P4 particles exposed to acidic solutions with a pH < 5 likely dissolve incongruently, leaving a slowly dissolving Si-rich layer. In such an environment, the dissolution rates of Na, Ca, and P are independent of the location of the S53P4 particle in the implant. Thus, the pH and fluid flow are critical factors for the dissolution of S53P4 bioactive glass particles.

Multifunctional poly(allylamine hydrochloride)/bioactive glass layer by layer surface coating on magnesium alloy for biomedical applications

The present study reports on a novel multilayer coating for biodegradable magnesium (Mg) alloy substrates. This coating contains soy protein hydrolysate (SPH), poly(allylamine hydrochloride) (PAH), and folic acid (FA) templated bioactive glass (BG) nano particles. The multilayer, designated as SPH/(PAH/BG)n, was coated onto an alkaline-treated Mg alloy surface (AMgS) through a dip-coating process with various numbers of cycles (n = 5and 7) using a layer-by-layer (LbL) assembly. The BG particles had an average diameter of 12.53 ± 2.22 nm and were embedded with therapeutic FA molecules. Scratch testing, wettability, and roughness tests showed excellent adherence of the SPH/(PAH/BG)7 coating on AMgS, making it suitable for cell attachment. Electrochemical measurements in Hanks balanced salt solution (HBSS) demonstrated that the SPH/(PAH/BG)7 coating improved the corrosion resistance of the Mg alloy. SPH/(PAH/BG)7 coated substrate showed a maximum protective efficacy of 98.4041 %, thanks to the bioactive nature of BG. High-resolution XPS and XRD analyses on SPH/(PAH/BG)7/AMgS confirmed the corrosion deposition of Mg(OH)2, MgHPO4.H2O, CaHPO4.H2O, SiO2, MgCO3 and CaCO3 on the substrate surface after immersion in HBSS for 10 d at 37 °C. The LbL coated Mg substrate also showed excellent cytocompatibility by hemolysis assay These results suggest that the SPH/(PAH/BG)7/AMgS material has multifunctional properties and can be a possible alternative for biomedical applications of Mg alloys.

Multifunctional bioactive coating on biomedical β-Ti12Mo6Zr2Fe alloy to improve corrosion protection and bioactivity properties

The present work presents and discusses the results of a comprehensive electrochemical study of the laser-textured β-Ti12Mo6Zr2Fe (TMZF) alloy coated with a bioactive layer (TMZF-BL), which was strategically designed to produce an improvement in corrosion resistance and impart bioactive properties to the TMZF alloy. The bioactivation of the laser-textured TMZF alloy was performed using a simple and innovative strategy that effectively coated the metal surface with a bioactive layer structured with bioactive glass (BG) particles functionalized with silicate and phosphate groups, acting as chemical anchoring agents. The electrochemical corrosion behavior of the bare and coated TMZF was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in Simulated Body Fluid (SBF) at 37 °C. Our results showed that the presence of the bioactive layer in the TMZF-BL samples shifted the corrosion potential (Ecorr) towards more noble values compared to polished TMZF (TMZF-P), and increased EIS modulus, suggesting that the corrosion resistance improved. The chemical stability of the bioactive coating was confirmed by the high polarization resistance and low capacitance values. Various analysis techniques surveyed the apatite-forming ability and growth on the surface of TMZF-P and TMZF-BL alloys as a function of soaking time in SBF. The bone-like apatite formation rate depended on the homogeneity of the bioactive layer covering the surface of the TMZF-BL alloy. Taken together, our results confirm the success of the experimental strategy designed to bioactivate the TMZF alloy and reinforce the potential of this approach for the development of highly stable bioactive implants, in addition to protecting the alloy surface against corrosion in the physiological environment.

Mesoporous Bioactive Glass-Incorporated Injectable Strontium-Containing Calcium Phosphate Cement Enhanced Osteoconductivity in a Critical-Sized Metaphyseal Defect in Osteoporotic Rats.

In this study, the in vitro and in vivo bone formation behavior of mesoporous bioactive glass (MBG) particles incorporated in a pasty strontium-containing calcium phosphate bone cement (pS100G10) was studied in a metaphyseal fracture-defect model in ovariectomized rats and compared to a plain pasty strontium-containing calcium phosphate bone cement (pS100) and control (empty defect) group, respectively. In vitro testing showed good cytocompatibility on human preosteoblasts and ongoing dissolution of the MBG component. Neither the released strontium nor the BMG particles from the pS100G10 had a negative influence on cell viability. Forty-five female Sprague-Dawley rats were randomly assigned to three different treatment groups: (1) pS100 (n = 15), (2) pS100G10 (n = 15), and (3) empty defect (n = 15). Twelve weeks after bilateral ovariectomy and multi-deficient diet, a 4 mm wedge-shaped fracture-defect was created at the metaphyseal area of the left femur in all animals. The originated fracture-defect was substituted with pS100 or pS100G10 or left empty. After six weeks, histomorphometrical analysis revealed a statistically significant higher bone volume/tissue volume ratio in the pS100G10 group compared to the pS100 (p = 0.03) and empty defect groups (p = 0.0001), indicating enhanced osteoconductivity with the incorporation of MBG. Immunohistochemistry revealed a significant decrease in the RANKL/OPG ratio for pS100 (p = 0.004) and pS100G10 (p = 0.003) compared to the empty defect group. pS100G10 showed a statistically higher expression of BMP-2. In addition, a statistically significant higher gene expression of alkaline phosphatase, osteoprotegerin, collagen1a1, collagen10a1 with a simultaneous decrease in RANKL, and carbonic anhydrase was seen in the pS100 and pS100G10 groups compared to the empty defect group. Mass spectrometric imaging by time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed the release of Sr2+ ions from both pS100 and pS100G10, with a gradient into the interface region. ToF-SIMS imaging also revealed that resorption of the MBG particles allowed for new bone formation in cement pores. In summary, the current work shows better bone formation of the injectable pasty strontium-containing calcium phosphate bone cement with incorporated mesoporous bioactive glass compared to the bioactive-free bone cement and empty defects and can be considered for clinical application for osteopenic fracture defects in the future.

UV-Cured Bio-Based Acrylated Soybean Oil Scaffold Reinforced with Bioactive Glasses.

In this study, a bio-based acrylate resin derived from soybean oil was used in combination with a reactive diluent, isobornyl acrylate, to synthetize a composite scaffold reinforced with bioactive glass particles. The formulation contained acrylated epoxidized soybean oil (AESO), isobornyl acrylate (IBOA), a photo-initiator (Irgacure 819) and a bioactive glass particle. The resin showed high reactivity towards radical photopolymerisation, and the presence of the bioactive glass did not significantly affect the photocuring process. The 3D-printed samples showed different properties from the mould-polymerised samples. The glass transition temperature Tg showed an increase of 3D samples with increasing bioactive glass content, attributed to the layer-by-layer curing process that resulted in improved interaction between the bioactive glass and the polymer matrix. Scanning electron microscope analysis revealed an optimal distribution on bioactive glass within the samples. Compression tests indicated that the 3D-printed sample exhibited higher modulus compared to mould-synthetized samples, proving the enhanced mechanical behaviour of 3D-printed scaffolds. The cytocompatibility and biocompatibility of the samples were evaluated using human bone marrow mesenchymal stem cells (bMSCs). The metabolic activity and attachment of cells on the samples' surfaces were analysed, and the results demonstrated higher metabolic activity and increased cell attachment on the surfaces containing higher bioactive glass content. The viability of the cells was further confirmed through live/dead staining and reseeding experiments. Overall, this study presents a novel approach for fabricating bioactive glass reinforced scaffolds using 3D printing technology, offering potential applications in tissue engineering.

Reduced Sodium Portions Favor Osteogenic Properties and Cytocompatibility of 45S5-Based Bioactive Glass Particles.

Besides its favorable biological properties, the release of sodium (Na) from the well-known 45S5-bioactive glass (BG) composition (in mol%: 46.1, SiO2, 24.5 CaO, 24.5 Na2O, 6.0 P2O5) can hamper its cytocompatibility. In this study, particles of Na-reduced variants of 45S5-BG were produced in exchange for CaO and P2O5 via the sol-gel-route resulting in Na contents of 75%, 50%, 25% or 0% of the original composition. The release of ions from the BGs as well as their impact on the cell environment (pH values), viability and osteogenic differentiation (activity of alkaline phosphatase (ALP)), the expression of osteopontin and osteocalcin in human bone-marrow-derived mesenchymal stromal cells in correlation to the Na-content and ion release of the BGs was assessed. The release of Na-ions increased with increasing Na-content in the BGs. With decreasing Na content, the viability of cells incubated with the BGs increased. The Na-reduced BGs showed elevated ALP activity and a pro-osteogenic stimulation with accelerated osteopontin induction and a pronounced upregulation of osteocalcin. In conclusion, the reduction in Na-content enhances the cytocompatibility and improves the osteogenic properties of 45S5-BG, making the Na-reduced variants of 45S5-BG promising candidates for further experimental consideration.

Sol-gel synthesis of spherical monodispersed bioactive glass nanoparticles co-doped with boron and copper

In this work, an optimized sol-gel process for the synthesis of spherical and monodispersed bioactive glass nanoparticles doped with boron and copper was developed, by investigating different synthesis parameters. The obtained glasses were characterized in terms of morphology, composition, dispersibility, structure and in vitro reactivity. The performed characterizations demonstrated that shape, dimension and dispersion can be tailored by acting on the timing of the addition of the catalyst and on the synthesis process, in particular the centrifugation step. The optimized glass particles showed a spherical shape, good ions incorporation and good dispersion. In vitro bioactivity test demonstrated that the boron and copper addition did not interfere with the glass ability to induce the precipitation of hydroxyapatite. The shape, dispersion, bioactive behavior and content of boron and copper of these novel bioactive glass particles make them very promising for both hard and soft tissue engineering applications.

Processing and characterization of aligned electrospun gelatin/polycaprolactone nanofiber mats incorporating borate glass (13-93B3) microparticles

Aligned biodegradable fibers incorporating bioactive glass particles are being highly investigated for tissue engineering applications. In this study, 5, 7 and 10 wt% melt-derived 1393B3 borate glass (BG) microparticles (average size: 3.15 µm) were incorporated in 83 wt% polycaprolactone (PCL) and 17 wt% gelatin (GEL) (83PCL/17GEL) solutions to produce aligned electrospun composite nanofiber mats. Addition of 5 wt% BG particles significantly increased the alignment of the nanofibers. However, further incorporation of BG particles led to reduced degree of alignment, likely due to an increase of viscosity. Mechanical tests indicated a tensile modulus and tensile strength of approximately 51 MPa and 3.4 MPa, respectively, for 5 wt% addition of 1393B3 BG microparticles, values considered suitable for soft tissue engineering applications. However, with the increasing amount of 1393B3 BG, the nanofiber mats became brittle. Contact angle was reduced after the addition of 5 wt% of 1393B3 BG particles from ∼45° to ∼39°. Cell culture studies with normal human dermal fibroblast (NHDF) cells indicated that 5 wt% 1393B3 BG incorporated nanofiber mats were cytocompatible whereas higher doping with 1393B3 BGs reduced biocompatibility. Overall, 5 wt% 1393B3 BG doped PCL/GEL nanofiber mats were aligned with high biocompatibility exhibiting desirable mechanical properties for soft tissue engineering, which indicates their potential for applications requiring aligned nanofibers, such as peripheral neural regeneration.

Electrophoretic deposition (EPD) of zein/bioactive glass composite coatings doped with F and Cu on titanium for biomedical applications

Coatings based on the natural polymer zein with the addition of SiO2-CaO-P2O5 bioactive glass (BG) particles doped with fluoride (BG-F) or a combination of fluoride and copper (BG-F-Cu) ions were deposited on titanium by electrophoretic deposition (EPD). The addition of BG improved the scratch resistance of the coatings. Additionally, the ion substitution in the BG structure did not affect the bioactivity. All composite coatings showed significantly improved viability of osteoblast-like MG-63 cells and enhanced antibacterial activity against Gram-negative E. coli after 24 h of incubation. Moreover, the presence of BG-F-Cu endowed antibacterial properties against Gram-positive S. aureus. The obtained results prove that the prepared coatings can be beneficial for the functionalization of orthopaedic and dental implants.

Electrospun the oriented silk fibroin/ bioactive glass @ silk fibroin/ polycaprolactone composite bi-layered membranes for guided bone regeneration

Guided bone regeneration (GBR) technology has been extensively used in the treatment of alveolar bone defects. However, existing GBR membranes still have great shortcomings in terms of biological activity and regeneration potential. In order to improve the performance of existing GBR membranes, based on the principle of GBR, this study starts from two aspects of material and structure, adding BG particles with good biological properties and introducing directional structure to construct a new type of double-layer composite fiber membrane, which can not only achieve the barrier function, but also induce the directional migration and differentiation of osteoblasts, so as to play the role of bone tissue regeneration and repair more efficiently. In this study, a bi-layer composite GBR membrane with oriented structure of silk fibroin (SF) / bioactive glass (BG) @ silk fibroin (SF) / polycaprolactone (PCL) was prepared by high-speed electrospinning technology, which achieved the dual functions of bone regeneration and barrier. The morphology, mechanical properties, secondary structure, biocompatibility and bioactivity of the oriented bi-layer composite membranes were studied systematically. The results showed that the fiber diameter and the pore size of SF/PCL composite membranes were obviously smaller than that of SF/BG composite membranes. Compared with SF and SF/BG composite membranes, the Young's modulus and tensile stress of the oriented SF/BG composite membranes is significantly increased, but the elongation at break is relatively decreased. The water contact angle of the material significantly decreased after the addition of BG particles and the introduction of orientated structure, which greatly improved the hydrophilicity of the composite membranes. Furthermore, the oriented SF/BG@SF/PCL exhibited higher cell adhesion and proliferation compared with the disordered SF/BG fiber membranes, and the introduction of BG particles significantly enhanced osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Besides, the barrier effect of the SF/PCL membrane was verified by L929 cells. The relatively dense structure leads to a good barrier effect as well as the obvious proliferation on the cells. This bi-layer composite SF/BG@SF/PCL membrane is a competitive candidate in the field of GBR technology and bone regeneration.

Bioactive and antibacterial glass particles as fillers in composite bone cements: Influence of amount and size on radio-opacity, bioactivity, mechanical and antibacterial properties

In this work, a bioactive and antibacterial glass has been added to a commercial PMMA-based bone cement to promote osteointegration and simultaneously limit bacterial contamination. The influence of the amount and size of glass powders on mechanical properties, radio-opacity, bioactivity and antibacterial effect of the composite cements has been estimated. The obtained results suggested that both filler's amount and size can affect the bending strength of the samples. The composites radio-opacity can be modulated by varying the amounts of glass and radio-opaque agent usually present in the commercial composition. The bioactive and antibacterial properties evaluation evidenced that introducing 10 wt.% of glass conferred a bioactive behaviour to the PMMA-based matrix and limited the bacterial contamination. Finally, an approach to technological transfer with controlled process parameters has been proposed.

Influence of Mesoporous Bioactive Glass Particles Doped with Cu and Mg on the Microstructure and Properties of Zein-Based Coatings Obtained by Electrophoretic Deposition

Cu- and Mg-doped mesoporous sol-gel bioactive glasses (MSGG) were developed and their microstructure was investigated. Selected biological tests were also performed to assess their suitability for the functionalization of polymer zein coatings. The electrophoretic deposition (EPD) conditions to obtain composite coatings on Ti-13Nb-13Zr substrates were determined. The coatings with excellent adhesion to the substrates were macroscopically uniform, exhibiting open porosity and high roughness. The surfaces of the samples coated with MSGG/zein coatings became more hydrophilic than the titanium alloy substrates. However, with increase of the volume fraction of glass particles in the coatings, the contact angle increased. The coated alloy showed enhanced resistance to electrochemical corrosion in Ringer’s solution. The chemical composition of the glass used in the coating affected the parameters of wettability and resistance to electrochemical corrosion. Both coating types showed an increase in the antibacterial properties against Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria compared to pure zein. However, no significant differences were observed after a 24 h-long test.

Effect of friction stir back extrusion on direction-dependent properties of gradient AZ91-bioactive glass composite rod

This research investigated the microstructure, mechanical properties, and corrosion resistance of friction stir back extruded AZ91-bioactive glass composites in parallel and perpendicular directions to the extrusion direction. The results showed that small grains are observed on the lateral surface, especially where bioactive glass is more prevalent. The grain size increases toward the center of the composite rod. The grain size and relative content of the β-Mg17Al12 phase shift from 30.2 ± 2.3 μm and 0.45 on the lateral surface of the composite rod to 37.4 ± 3.2 μm and 0.12 at the center of the composite rod, respectively. The corrosion resistance and hardness of the lateral surface area of the composite rod are 23 and 26%, respectively, higher than the corrosion resistance and hardness of the transverse surface. The lateral surface of the composite rod shows 74% higher corrosion resistance than the lateral surface of friction stir back extrusion processed wire without bioactive glass particles.

PLGA/BGP/Nef porous composite restrains osteoclasts by inhibiting the NF-κB pathway, enhances IGF-1-mediated osteogenic differentiation and promotes bone regeneration

BackgroundNovel bone substitutes are urgently needed in experimental research and clinical orthopaedic applications. There are many traditional Chinese medicines that have effects on bone repair. However, application of natural medicines in traditional Chinese medicine to bone tissue engineering and its mechanism were rarely reported.ResultsIn this study, the osteogenic ability of bioactive glass particles (BGPs) and the osteogenic and osteoclastic ability of neferine (Nef) were fused into PLGA-based bone tissue engineering materials for bone regeneration. BGPs were prepared by spray drying and calcination. Particles and Nef were then mixed with PLGA solution to prepare porous composites by the phase conversion method. Here we showed that Nef inhibited proliferation and enhanced ALP activity of MC3T3-E1 cells in a dose‐ and time‐dependent manner. And the composites containing Nef could also inhibit RANKL‐induced osteoclast formation (p < 0.05). Mechanistically, the PLGA/BGP/Nef composite downregulated the expression of NFATC1 by inhibiting the NF-κB pathway to restrain osteoclasts. In the other hands, PLGA/BGP/Nef composite was first demonstrated to effectively activate the IGF-1R/PI3K/AKT/mTOR pathway to enhance IGF-1-mediated osteogenic differentiation. The results of animal experiments show that the material can effectively promote the formation and maturation of new bone in the skull defect site.ConclusionsThe PLGA/BGP/Nef porous composite can restrain osteoclasts by inhibiting the NF-κB pathway, enhance IGF-1-mediated osteogenic differentiation and promotes bone regeneration, and has the potential for clinical application.

Friction extrusion of AZ91/bioactive glass gradient composite

The effect of the pre-friction extrusion microstructure of AZ91 billet on the microstructure, mechanical properties, and corrosion resistance of AZ91-bioactive glass surface composite rods was investigated. The results show that friction extrusion on AZ91 alloy billet with cast microstructure results in agglomerated bioactive glass particles in the composite rod microstructure. Compared to as-cast AZ91 alloy, friction extrusion on AZ91 alloy billet with cast microstructure results in 93% more corrosion resistance. Also, friction extrusion on AZ91 alloy billet with extruded microstructure leads to a gradient AZ91-bioactive glass composite rod with ultimate tensile strength, yield strength, and corrosion resistance of 9, 2, and 74% higher than AZ91 alloy rods, respectively.