Soaking In Simulated Body Fluid Research Articles

Odontogenic and anti-inflammatory effects of magnesium-doped bioactive glass in vital pulp therapy.

This study aimed to investigate the effects of magnesium-doped bioactive glass (Mg-BG) on the mineralization, odontogenesis, and anti-inflammatory abilities of human dental pulp stem cells (hDPSCs). Mg-BG powders with different Mg concentrations were successfully synthesized via the sol-gel method and evaluated using X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Apatite formation was observed on the surfaces of the materials after soaking in simulated body fluid. hDPSCs were cultured with Mg-BG powder extracts in vitro, and no evident cytotoxicity was observed. Mg-BG induced alkaline phosphatase (ALP) expression and mineralization of hDPSCs and upregulated the expression of odontogenic genes, including those encoding dentin sialophosphoprotein, dentin matrix protein 1, ALP, osteocalcin, and runt-related transcription factor 2. Moreover, secretion of inflammatory cytokines (interleukin [IL]-4, IL-6, IL-8, and tumor necrosis factor-alpha) was substantially suppressed by Mg-BG. Collectively, the results of this study suggest that Mg-BG has excellent in vitro bioactivity and is a potential material for vital pulp therapy for inflamed pulps.

Influence of glass composition on the network structure and mineralization of europium containing mesoporous bioactive glass nanoparticles

A mesoporous bioactive glass nanoparticle (MBN) containing functional elements effectively enhances its healing effect in medical applications. The MBN mainly comprises SiO2 structure and controls the composition by incorporating functional ions into the glass network, which affects the network structure and bioactivity. Europium has already been identified to have luminescence properties for drug delivery systems and positively affects osteogenic properties. Therefore, in this study, we recognize the changes in the glass network according to different compositions with the same amount of europium oxide (10 mol%).The MBN compositions with SiO2–CaO–P2O5–Eu2O3 were synthesized by sol-gel method, and we control the contents of SiO2 and CaO, respectively. The obtained Eu-containing MBNs had spherical morphology with mesoporous structure. Changes in bioactivity and mineralization properties would be investigated to apply the dental products. After soaking in simulated body fluid (SBF), Eu-containing MBNs with substituted SiO2 form an amorphous calcium phosphate phase on their surface. The results indicate that incorporating Eu in the bioactive glass network is an effective strategy for mineralization and developing novel multifunctional MBNs for bone tissue and drug delivery carriers.

Porous Ti3SiC2 ceramics with improved osteogenic functions via biomineralization as load-bearing bone implants

Ti3SiC2 ceramics exhibit excellent mechanical properties and good biocompatibility, rendering them promising bone substitutes for load-bearing conditions. However, the bone integration and osteogenic ability of Ti3SiC2 ceramics remain unclear. Herein, porous Ti3SiC2 ceramics were prepared and systematically investigated as bone scaffolds. The Ti3SiC2 scaffolds with a porosity of 62.9 % ± 2.5 % showed high compressive strength ∼68.12 ± 4.33 MPa. Silicon hydroxyl groups formed on the surface of Ti3SiC2 after soaking in simulated body fluid, which played a critical role in the apatite mineralization of the scaffolds. Biomineralization of Ti3SiC2 scaffolds was found when implanted subcutaneously in the rat dorsum for 2 weeks, demonstrating good osteogenesis ability. The apatite mineralization of the Ti3SiC2 scaffold facilitated the polarization of RAW264.7 cells from M1 to M2 phenotype, which also promoted the differentiation of MC3T3-E1 cells. The porous Ti3SiC2 scaffolds improved osteointegration and bone regeneration after implantation in rabbit femoral defects. Impressively, the number of the newly formed trabeculae in the Ti3SiC2 group was three times of the control group after implantation for 8 weeks, showing excellent bone defect repair. This work demonstrates that Ti3SiC2 implants with improved biological functions likely via in-situ biomineralization are promising candidates for bone regeneration.

The role of MgO on physical and bioactive properties of borophosphate glasses for biomedical applications

In this work, a novel series of borophosphate glasses of the system 40B2O3–25P2O5–(20-x)Na2O–15CaF2–xMgO (x = 0, 2.5, 5, 7.5, and 10 mol%) were synthesized using the melt-quenching technique. The effect of replacing Na2O with MgO in the glasses was analyzed by the physical and bioactive properties. The glasses were characterized by density, molar volume, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Differential thermal analysis (DTA), bioactivity tests in simulated body fluid (SBF), pH measurements, mass loss, and verification of cellular compatibility in RAW 247 murine macrophages. XRD and FTIR analyses were performed before and after immersion in SBF to verify the bioactivity. Density, molar volume and FTIR results before SBF showed structural changes in the glasses due to the addition of MgO. The pH and mass loss measurements allowed to verify the degradation behavior of the glass series as a function of MgO concentration. The DTA data showed an increase in Tg, Tx, and thermal stability due to the increase in MgO addition. XRD and FTIR analyses after SBF soaking showed superficial formation of apatites and other calcium phosphates of biological interest in the samples, attesting the bioactivity. Cytotoxicity assessed by MTT assay on the cell line RAW 247 showed that at a concentration of 500 μg/mL all glasses were compatible (non-cytotoxic). The results suggest that the synthesized glasses are bioactive, with the sample containing 5 mol% MgO exhibiting the bioactivity and biocompatibility required for biomaterial applications.

Development and characterisation of block copolymer/bioactive glass and block copolymer/TCP composite coatings obtained by EPD

The aim of this work focused on the synthesis of composite coatings based on poly(dimethylsiloxane-block-ε-caprolactone), Bioglass® (BG) and tricalcium phosphate (TCP) particles deposited on stainless steel plates obtained by electrophoretic deposition (EPD) technique. In vitro assessment was performed in simulated body fluid (SBF) to evaluate the potential uses of these coatings in tissue engineering. Thermal characterization from thermogravimetric analysis (TGA) revealed that experimental [Polymer]:[mineral]e wt/wt ratios were 32:68 and 26:74 for coatings with BG and TCP, respectively. In addition, all coatings exhibited thicknesses ranging from 45.3 μm to 59.9 μm. Finally, the growth of a hydroxyapatite (HA) layer on the coatings, after soaking in simulated body fluid (SBF), was evidenced by X-ray diffraction analysis. This last result suggests that the obtained coatings could be used as promising materials in bone tissue regeneration.

Regulation of the antibiotic elution profile from tricalcium phosphate bone cement by addition of bioactive glass

This work aimed at tailoring of different properties of antibacterial drug delivery Ca-phosphate cements by incorporation of bioactive glass (BG). The cements were prepared from beta-tricalcium phosphate cement (β-TCP) and BG based on 50 SiO2—20 CaO—15 Na2O—7 B2O3—4 P2O5—4 Al2O3 wt% with different percentages of BG [5, 10, 15, and 20% (w/w)]. The composite cements were characterized by XRD, FTIR, and TEM. Moreover, in vitro bioactivity and biodegradation were evaluated in the simulated body fluid (SBF) at 37 °C. In addition, physical properties and mechanical strength were determined. Also, the effect of glass addition on the drug release profile was examined using gentamicin. Finally, the antimicrobial activity was studied against Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumonia bacteria, one unicellular fungal strain (Candida albicans), and one multicellular fungal strain (Mucor racemosus). The results showed that after soaking in SBF, the compression strength values ranged from 14 to 36 MPa, the bulk densities and porosities were within 1.35 to 1.49 g/cm3 and 51.3 to 44.71%, respectively. Furthermore, gentamicin was released in a sustained manner, and BG decreased the released drug amount from ~ 80% (in pure β-TCP) to 47–53% in the composite cements. A drug release profile that is sustained by all samples was achieved. The antimicrobial test showed good activity of gentamicin-conjugated cements against bacteria and fungi used in this study. Additionally, cytotoxicity results proved that all samples were safe on MG-63 cells up to 50 µg/mL with no more than 7–12% dead cells. From the view of the physico-mechanical properties, bioactivity, biodegradation, and drug release rate, 20BG/β-TCP sample was nominated for practical bone grafting material, where it showed appropriate setting time and a relatively high mechanical strength suitable for cancellous bone.

Fabrication and characterization of 3D-printed composite scaffolds of coral-derived hydroxyapatite nanoparticles/polycaprolactone/gelatin carrying doxorubicin for bone tissue engineering

In this study, nanocomposite scaffolds of hydroxyapatite (HA)/polycaprolactone (PCL)/gelatin (Gel) with varying amounts of HA (42–52 wt. %), PCL (42–52 wt. %), and Gel (6 wt. %) were 3D printed. Subsequently, a scaffold with optimal mechanical properties was utilized as a carrier for doxorubicin (DOX) in the treatment of bone cancer. For this purpose, HA nanoparticles were first synthesized by the hydrothermal conversion of Acropora coral and characterized by using different techniques. Also, a compression test was performed to investigate the mechanical properties of the fabricated scaffolds. The mineralization of the optimal scaffold was determined by immersing it in simulated body fluid (SBF) solution for 28 days, and the biocompatibility was investigated by seeding MG-63 osteoblast-like cells on it after 1–7 days. The obtained results showed that the average size of the synthesized HA particles was about 80 nm. The compressive modulus and strength of the scaffold with 47 wt. % HA was reported to be 0.29 GPa and 9.9 MPa, respectively, which was in the range of trabecular bones. In addition, the scaffold surface was entirely coated with an apatite layer after 28 days of soaking in SBF. Also, the efficiency and loading percentage of DOX were obtained as 30.8 and 1.6%, respectively. The drug release behavior was stable for 14 days. Cytotoxicity and adhesion evaluations showed that the fabricated scaffold had no negative effects on the viability of MG-63 cells and led to their proliferation during the investigated period. From these results, it can be concluded that the HA/PCL/Gel scaffold prepared in this study, in addition to its drug release capability, has good bioactivity, mechanical properties, and biocompatibility, and can be considered a suitable option for bone tumor treatment.Graphical

Hydroxycarbonate apatite formation, cytotoxicity, and antibacterial properties of rubidium-doped mesoporous bioactive glass nanoparticles

Rubidium (Rb) has been shown to impact biological activity. This work synthesized Rb-doped mesoporous bioactive glass nanoparticles (MBGNs) based on the composition 70SiO2–30CaO mol% with a sol-gel method. Rb2O was substituted for CaO in concentrations of 5 and 10 mol%. The influence of Rb incorporation on the hydroxycarbonate apatite (HCA) formation, cytotoxicity, and antibacterial capacity of particles was evaluated. XRD analysis confirmed the amorphous structure of the particles. In vitro, biomineralization studies showed HCA on the surface of MBGN and Rb-doped MBGN pellets after 7 days of soaking in simulated body fluid (SBF). An inhibition zone of Escherichia coli (E.coli) and Staphylococcus aureus (S. aureus) around Rb-doped MBGN pellets was detected, while MBGN pellets did not show any inhibition zone. Additionally, MC3T3-E1 pre-osteoblastic cells demonstrated cytocompatibility when exposed to Rb-MBG suspensions at different concentrations of up to 250 µg/ml. Based on their overall properties, Rb-containing MBGNs are proposed for biomedical applications, such as filler nanoparticles in composite bone scaffolds.

Applying the Alkali-Activation Method to Encapsulate Silicon Nitride Particles in a Bioactive Matrix for Augmented Strength and Bioactivity.

The development of bioactive ceramics still poses challenges in finding a good compromise between bioactivity and mechanical robustness. Moreover, a facile, low-cost and energy-saving synthesis technique is still needed. This study concerns the synthesis of a bioactive material by growing a bioactive Na-Ca-Mg-Si-based ceramic matrix produced using the alkali-activation method on silicon nitride (Si3N4) particles. This technique simultaneously forms the matrix precursor and functionalizes the Si3N4 particles' surface. The optimal strength-bioactivity compromise was found for the composition containing 60 wt.% Si3N4 and 40 wt.% of the matrix exhibiting good compressive strength of up to 110 MPa and extensive precipitation of hydroxyapatite on the sample surface after 7 days of soaking in simulated body fluid. This innovative approach merging strong non-oxide binary ceramics with the versatile and low-cost alkali-activation method holds great expectations for the future in biomaterials.

Characterization, bioactivity, antibacterial and cytotoxicity of inexpensive soda-lime-silica glass/tetracalcium phosphate composites

Composite biomaterials were created by sintering soda-lime-silica glass powder and tetracalcium phosphate powder. Sintering of the samples at 1200 °C/2h led to the formation of wollastonite, calcium phosphate, and cristobalite before soaking in simulated body fluid (SBF). However, after soaking for two weeks in SBF the hydroxyapatite, wollastonite, and cristobalite phases appeared with relatively intense in hydroxyapatite phase on sample surfaces. The microstructure shows micro-scale particles on the sample surface after soaking in SBF. The bulk densities and porosities were within 1.82453–1.9672 g/cm3 and 15.0621–34.1657 % respectively whereas compressive strength values were between 42.79 and 111.26 MPa. Since the increase of the porosity in the direction of high addition of phosphate portion while strengths were high in opposite values. The biocompatibility in SBF increases with increasing the SLS glass portion and the SEM micrographs show fine spherical crystals, within 20–200 nm, of hydroxyapatite phase on composite surfaces. The FTIR spectrum after soaking in SBF indicates the presence of phosphate bands in all samples and the intensity of these bands increases as the SLS glass percentage increases. The degradation of composite samples decreases in the direction of an increase in the phosphate portion which led to a decrease in the porosity and an increase in both density and strength. Pseudomonas aeruginosa and Staphylococcus aureus, the two examined bacteria, both showed the establishment of growth inhibition zones in the disk diffusion assay. All samples were shown to be biocompatible by the cytotoxicity test conducted on the human normal fibroplast cell line (BJ1). In light of this, the cytotoxicity analysis demonstrated that the highest soda-lime-silica glass sample (SLP55), which has potential uses in the dental and bone fields, was entirely safe for use with the human normal fibroplast cell line (BJ1).

Novel bone cement based on calcium phosphate composited CNT curcumin with improved strength and antitumor properties.

In this study, carboxylated carbon nanotube (CNT)-loaded curcumin (CUR) was blended into calcium phosphate cement (CPC) owing to the poor mechanical properties and single function of CPC as a bone-filling material, and CNT-CUR-CPC with improved strength and antitumor properties was obtained. The failure strength, hydrophilicity, in vitro bioactivity, bacteriostatic activity, antitumor activity, and cell safety of CNT-CUR-CPC were evaluated. The experimental results indicated that the failure strength of CNT-CUR-CPC increased from 25.05 to 45.05 MPa (p < 0.001) and its contact angle decreased from 20.37° to 15.27° (p < 0.001) after the CNT-CUR complex was added into CPC at the rate of 5 wt% and blended. Following soaking in simulated body fluid (m-SBF), the main components of CNT-CUR-CPC were hydroxyapatite (HA) and carbonate hydroxyapatite (HCA). The incorporation of CNT-CUR was beneficial for the deposition of PO43- and CO32-, and it promoted the crystallization of HA and HCA. For CNT-CUR-CPC, the inhibition zone diameter on Staphylococcus aureus was 10.2 ± 1.02 mm (p < 0.001) and it exhibited moderate sensitivity, whereas the inhibition zone diameter on Escherichia coli was 8.3 ± 0.23 mm (p < 0.001) and it exhibited low sensitivity. When compared with the CPC, the cell proliferation rate (RGR %) of the CNT-CUR-CPC decreased by 7.73% (p > 0.05) at 24 h, 17.89% (p < 0.05) at 48 h, and 24.43% (p < 0.001) at 72 h when MG63 cells were cultured on it. In particular, after the MG63 cells were cultured with the CNT-CUR-CPC for 48 h, the number of newly proliferating MG63 cells was significantly reduced, and their growth and adhesion on the surface of the CNT-CUR-CPC were inhibited when compared with the CPC. When 3T3-E1 cells were exposed to the m-SBF immersion solution of CNT-CUR-CPC, the cell proliferation rate (RGR %) was ≥80% (p > 0.05) and the cytotoxicity grade was 0-1. The 3T3-E1 cells were cultured with the m-SBF soaking solution of CNT-CUR-CPC for 24 h, and no significant changes in cell morphology or cytotoxicity were observed. After the 3T3-E1 cells were cultured on CNT-CUR-CPC for 48 h, they could stick to and grow on its surface without adverse reactions. CNT-CUR-CPC had a hemolysis rate of 4.3% (p > 0.05) and did not result in hemolysis and hemagglutination. The obtained CNT-CUR-CPC scaffold material exhibited effective antibacterial activity and cell safety, and could achieve a certain antitumor effect, which has a wide application potential in bone tissue engineering.

Effect of microstructure and texture of AZ31 magnesium alloy substrate on nucleation and growth of biomimetic calcium phosphate coating

Magnesium has a special place in biomedical applications due to its biocompatibility and biodegradability properties. The high corrosion rate of magnesium in the body environment requires the use of a biocompatible coating such as calcium phosphate. In this paper, the effect of microstructure and crystalline texture of AZ31 magnesium alloy substrate on the morphology of calcium phosphate coating and the corrosion behavior of the material was investigated. The results imply that apatite crystals can form and grow on the surfaces of the biomimetic coating after soaking in simulated body fluid (SBF). The corrosion behavior of the material was investigated using an electrochemical polarization test in SBF solution for 3 days. The results showed that changes in the microstructure and crystalline texture of the substrate changed the coating morphology so that the growth of calcium phosphate changed from a rod-shaped with a diameter of 100–150 nm to a blade-shaped with a thickness of 20–50 nm. An increase in the corrosion resistance of the coated specimens with the corrosion rate of 0.65 mm/year was obtained compared to the uncoated specimen with the corrosion rate of 2.62 mm/year.

Role of porosity in the strength, dielectric properties, and bioactivity of hardystonite ceramic material for use in bone tissue engineering applications

This work aimed to investigate the relationship between porosity, mechanical and electrical properties, and bioactivity of dense and porous hardystonite (HT; Ca2ZnSi2O7) bioceramic. Therefore, HT nanopowders were prepared to which different proportions of space holder agent were added and sintered. The microstructure of the resulting dense and porous samples was investigated by scanning electron microscopy (SEM). The mechanical properties of all samples were measured. The bioactivity of the samples prepared after soaking in simulated body fluid (SBF) for 7 and 14 days was assessed by SEM. In addition, the relationship between the incubation duration and the electrical and dielectric properties of HT cultured in SBF solution has been examined. The SEM micrographs showed that the samples soaked in SBF for 7 days showed no bioactive behavior, thanks to the chemical stability of HT. However, prolonged soaking of the samples in SBF solution for 14 days considerably improved their bioactivity behavior. These results were related to the electrical conductivity of the samples, as the samples soaked for 7 days showed a slight decrease in their values as follows: 2.19, 2.68, 5.75, and 8.94%, while the electrical conductivity values increased for all samples soaked for 14 days by 7.35, 16.9, 19.6, and 26.5%. Importantly, a significant part of encouraging fracture healing is played by this enhanced electrical conductivity. The outcomes obtained provide hope for the future use of HT in bone tissue engineering purposes.

High Density Polyethylene/Calcium Silicate Hybrid Composite: Preparation, Characterization and &lt;i&gt;In-Vitro&lt;/i&gt; Bioactivity

The high density polyethylene/calcium silicate (HDPE/CS) hybrid composites were prepared using a twin-screw extruder and shaped into test specimens using a compression molding machine. The CS loadings, limited to a total of 20 %vol, were incorporated in HDPE matrix. The morphological behavior, thermal behavior, mechanical properties and bioactivity of the composites were investigated and compared with the neat HDPE under identical conditions. It was found that poor dispersion of the CS particles was observed in the composites with high CS loadings because of only weak interaction between CS particles and HDPE. The percentage of HDPE crystallinity was insignificantly changed when adding CS particles in the HDPE/CS composites. The stiffness of the HDPE/CS hybrid composites was strongly improved and reached the maximum values of flexural and compressive moduli at 1190 MPa (35% greater than the neat HDPE) and 581 Ma (17% greater than the neat HDPE), respectively, with 15 % CS loading. The higher the CS loading, the greater the hardness of the HDPE/CS composites were seen. However, the flexural strength of the HDPE/CS composites (up to 15% CS loading) was not considerably altered. Moreover, both flexural and compressive properties were lowered with higher CS content (20%) due to the generated voids in the HDPE/CS composites. After soaking in simulated body fluid (SBF) at 36.5°C for 7–49 days, the HDPE/CS composites could induce the formation of ball-like HA aggregates covering on the composite surface, indicating its bioactivity. This research successfully prepared HDPE/CS hybrid composites with fast rate bioactivity and their modulus and strength values were within those for human trabecular bone. Therefore, the HDPE/CS hybrid composites had potentially used as bioactive materials for medical applications.

Study on a co-hybrid nano-hydroxyapatite with lignin derivatives and alendronate and the reinforce effect for poly(lactide-co-glycolide)

A novel co-hybrid nano-apatite (n-HA) by introducing lignin derivatives (LDs) and alendronate (ALE) was designed to reinforce poly(lactide-co-glycolide) (PLGA). The effect of different addition methods and contents of LDs, lignin derivatives sorts of lignosulfonate (LS), alkali lignin (AL) and carboxymethyl lignin (CML), and the addition order of ALE on the dispersion of hybrid n-HA, and reinforce effective for PLGA were investigated by FTIR, XRD, TEM, TGA, XPS, N2 adsorption/desorption, zeta potential, dispersion experiments, universal testing machine, SEM, DSC and POM. The results showed that the addition order could regulate the growth of n-HA crystal planes by binding with Ca2+, and co-hybrid HA by LDs and ALE possessed better dispersion owing to the synergistic effect. Moreover, 10 wt% LS-ALE-n-HA displayed the best reinforce effect, and the tensile strength of composite was 24.43 % higher than that of PLGA, even 15 wt% LS-ALE-n-HA was added, it still exhibited reinforce effect for PLGA. In vitro soaking in simulated body fluid (SBF) results indicated that LS-ALE-n-HA delayed tensile strength reduce of PLGA and promoted bone-like apatite deposition. The cell proliferation results demonstrated that the hybrid n-HA by the introduction of ALE endowed PLGA with better cell adhesion and proliferation.

Preparation and Characterization of a Novel Tragacanth Gum/Chitosan/Sr-Nano-Hydroxyapatite Composite Membrane.

It is a great challenge to obtain an ideal guided bone regeneration (GBR) membrane. In this study, tragacanth gum (GT) was introduced into a chitosan/nano-hydroxyapatite (CS/n-HA) system. The effects of different component ratios and strontium-doped nano-hydroxyapatite (Sr-HA) on the physical-chemical properties and degradation behavior of the CS/Sr-n-HA/GT ternary composite membrane were investigated using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), contact angle, electromechanical universal tester and in vitro soaking in simulated body fluid (SBF). The results showed that CS could be ionically crosslinked with GT through electrostatic interaction, and Sr-n-HA was loaded via hydrogen bond, which endowed the GT/CS/n-HA composite membrane with good tensile strength and hydrophilicity. In addition, the results of immersion in SBF in vitro showed that CS/n-HA/GT composite membranes had different degradation rates and good apatite deposition by investigating the changes in pH value, weight loss, water absorption ratio, SEM morphology observation and tensile strength reduction. All results revealed that the CS/Sr-n-HA/GT (6:2:2) ternary composite membrane possessed the strongest ionic crosslinking of GT and CS, which was expected to obtain more satisfactory GBR membranes, and this study will provide new applications of GT in the field of biomedical membranes.

Tannic acid complex encapsulation high load nano-silica self-healing coating for protection of stainless steel

Benzotriazole (BTA) inhibitor was coated in mesoporous silica nanoparticles (MSNs) by tannic acid complex (TAC) deposition. The tannic acid complex film was used as a pH control release valve, which could sensitively feedback and control the release of BTA. MSNs-BTA@TAC was added to the organic–inorganic composite coating, a self-healing coating with pH feedback sensitivity and corrosion compensation function was prepared. The results of electrochemical impedance spectroscopy (EIS) showed that the organic/inorganic composite coating containing 2 wt% MSNs-BTA@TAC nanoparticles showed obvious self-healing effect after soaking in simulated body fluids for 20 days, and its low-frequency impedance modulus increased from 4.9 × 104 Ωcm2 to 9.2 × 105 Ωcm2. The long-term corrosion resistance and self-healing effect of the coating were verified in simulated body fluids.

Making foam-like bioactive glass scaffolds by vat photopolymerization

This study explores the feasibility of bioactive glass scaffolds by using a stereolithographic technology (digital light processing-based vat photopolymerization) as fabrication method and the micro-tomographic reconstruction of an open-cell polymeric sponge as input virtual model to the printing system, in the attempt to replicate the trabecular architecture of cancellous bone. Additively-manufactured scaffolds were investigated from morphological (scanning electron microscopy), microstructural (X-ray diffraction), mechanical (compressive tests) and bioactive viewpoints (immersion studies in simulated body fluid (SBF)). Well-densified foam-like glass scaffolds were obtained after sintering, provided with suitable mechanical properties (compressive strength 21.9 ± 6.2 MPa, elastic modulus 4.8 ± 0.1 GPa, Weibull modulus 3.9) for bone-contact applications. The formation of a hydroxyapatite layer on scaffold struts after soaking in SBF also demonstrated the in vitro bioactivity of the printed structures.

Polyvinylpyrrolidone Nanofibers Incorporating Mesoporous Bioactive Glass for Bone Tissue Engineering.

Composite biomaterials that combine osteoconductive and osteoinductive properties are a promising approach for bone tissue engineering (BTE) since they stimulate osteogenesis while mimicking extracellular matrix (ECM) morphology. In this context, the aim of the present research was to produce polyvinylpyrrolidone (PVP) nanofibers containing mesoporous bioactive glass (MBG) 80S15 nanoparticles. These composite materials were produced by the electrospinning technique. Design of experiments (DOE) was used to estimate the optimal electrospinning parameters to reduce average fiber diameter. The polymeric matrices were thermally crosslinked under different conditions, and the fibers' morphology was studied using scanning electron microscopy (SEM). Evaluation of the mechanical properties of nanofibrous mats revealed a dependence on thermal crosslinking parameters and on the presence of MBG 80S15 particles inside the polymeric fibers. Degradation tests indicated that the presence of MBG led to a faster degradation of nanofibrous mats and to a higher swelling capacity. The assessment of in vitro bioactivity in simulated body fluid (SBF) was performed using MBG pellets and PVP/MBG (1:1) composites to assess if the bioactive properties of MBG 80S15 were kept when it was incorporated into PVP nanofibers. FTIR and XRD analysis along with SEM-EDS results indicated that a hydroxy-carbonate apatite (HCA) layer formed on the surface of MBG pellets and nanofibrous webs after soaking in SBF over different time periods. In general, the materials revealed no cytotoxic effects on the Saos-2 cell line. The overall results for the materials produced show the potential of the composites to be used in BTE.

Bioceramics in the CaMgSi2O6–Li2O System: A Glass‐Ceramic Strategy for Excellent Mechanical Strength and Enhanced Bioactivity by Spontaneous Elemental Redistribution

AbstractA novel glass‐ceramic strategy for synthesizing mixed phase diopside (CaMgSi2O6)–lithium oxide (Li2O) bioceramics with excellent mechanical strength, superior biodegradation resistance, low environmental pH impact, enhanced bioactivity, and reasonable biocompatibility is developed for biomedical applications. The substitution of Li2O for MgO in CaMgSi2O6 stimulates the formation of secondary phases: CaSiO3, Li2Si2O5, SiO2, Li2SiO3, and Li2Ca2Si5O13. The evolution of CaSiO3 improves the surface hydroxyapatite (HAp) formation but lowers the mechanical strength and biological resistance, while the amorphous Li2Si2O5 phase tremendously reinforces the bioceramics by densifying the microstructure, indicating the simultaneous enhancement of bioactivity, mechanical strength, and durability. The promoted HAp formation is induced by the elemental redistribution where Mg elements are concentrated in large CaMgSi2O6 grains embedded in Li2Si2O5 amorphous matrix, which hinders the Mg2+ release and its readsorption by HAp. The cell viability is affected by Li2O substitution because of the high‐dose Li+. In the current work, Li0.25 (25 mol% Li2O) has the highest hardness (700 Hv as sintered and 197 Hv after simulated body fluid soaking), lowest weight loss (≈0.6 wt%), lowest pH variation (≈8.1), efficient HAp formation, and reasonable cell viability (70.5%), demonstrating its remarkable potential for bone implant applications due to the synergistic structural densification and biological improvement.