Composite Bone Cement Research Articles

Lyophilized platelet rich fibrin and gelatin incorporated bioadhesive bone cement composite for repair of mandibular continuity defects

Mandibular continuity defects stem from conditions such as malignancies, trauma, cysts, osteomyelitis and osteoradionecrosis, presenting significant challenges. If mandibular reconstruction fails, it can result in facial collapse, causing significant aesthetic and functional concerns for the patient. In the present study we developed a bio-adhesive Bone Cement (BC) enriched with lyophilised PRF and gelatin to enhance bone repair and induce regeneration. The developed BC consisted of a mixture of Tetracalcium Phosphate (TTCP) and O-Phospho-l-serine (OPLS) in addition to lyophilised Platelet Rich Fibrin (PRF) for sustained growth factor release and gelatin (GE) for improved cement resorption. It is primarily designed for in-situ application, conforming to the shape and size of the defect for effective bone repair and regeneration. The study evaluated four groups: (i) BC (control), (ii) BC-GE (control), (iii) BC-PRF, and (iv) BC-GE-PRF. All the four groups were characterised using FTIR, SEM and XRD. The mechanical studies of the prepared beads exhibited a significant increase in the compressive strength of the PRF loaded bone cement composites. In vitro degradation study of the beads over a 60-day period revealed a significantly higher percentage of bone cement resorption in the gelatin-incorporated groups, BC-GE (44 ± 0.5 %), and BC-GE-PRF (45 ± 2 %). The assessment of growth factor release (TGF-β and VEGF) using ELISA revealed a prolonged and sustained release of both growth factors over a 28-day period. In vitro studies were performed on human Dental Follicle Stem Cells (DFSCs) to assess cell attachment, proliferation, mineralisation and osteogenic differentiation. These studies clearly depicted that BC-PRF and BC-GE-PRF showed significantly greater proliferation of DFSCs. Furthermore, BC-PRF and BC-GE-PRF samples exhibited notably elevated expression of Runx2 and OPN (osteogenic markers), as well as a higher intensity of alizarin red stain (mineralisation). Therefore, it was concluded that PRF incorporated bioadhesive bone cement composites greatly enhance the cell attachment, proliferation, mineralisation and osteogenic differentiation of the DFSCs. Thus, the PRF and gelatin incorporated bone cement composites is expected to facilitate effective and faster bone regeneration and healing in a wide range of dental and maxillofacial defects.

Design and Manufacture of Bone Cements Based on Calcium Sulfate Hemihydrate and Mg, Sr-Doped Bioactive Glass.

In the present study, a novel composite bone cement based on calcium sulfate hemihydrate (CSH) and Mg, Sr-containing bioactive glass (BG) as solid phase, and solution of chitosan as liquid phase were developed. The phase composition, morphology, setting time, injectability, viscosity, and cellular responses of the composites with various contents of BG (0, 10, 20, and 30 wt.%) were investigated. The pure calcium sulfate cement was set at approximately 180 min, whereas the setting time was drastically decreased to 6 min by replacing 30 wt.% glass powder for CSH in the cement solid phase. BG changed the microscopic morphology of the set cement and decreased the size and compaction of the precipitated gypsum phase. Replacing the CSH phase with BG increased injection force of the produced cement; however, all the cements were injected at a nearly constant force, lower than 20 N. The viscosity measurements in oscillatory mode determined the shear-thinning behavior of the pastes. Although the viscosity of the pastes increased with increasing BG content, it was influenced by the frequency extent. Pure calcium sulfate cement exhibited some transient cytotoxicity on human-derived bone mesenchymal stem cells and it was compensated by introducing BG phase. Moreover, BG improved the cell proliferation and mineralization of extracellular matrix as shown by calcein measurements. The results indicate the injectable composite cement comprising 70 wt.% CSH and 30 wt.% Mg, Sr-doped BG has better setting, mechanical and cellular behaviors and hence, is a potential candidate for bone repair, however more animal and human clinical evaluations are essential.

Tunicate cellulose nanocrystals reinforced modified calcium sulfate bone cement with enhanced mechanical properties for bone repair

Considering the poor mechanical properties of bone cement, its practical application has always been limited. In this study, we introduced tunicate cellulose nanocrystals (TCNCs) into calcium sulfate bone cement for the first time, and multiple enhanced composite bone cement was prepared by the condensation reflux method. Firstly, high-strength modified calcium sulfate hemihydrate (CSH) bone cement was successfully prepared by using tartaric acid, a crystal modifier with a chiral structure. Secondly, the inclusion of TCNCs not only exhibited significant reinforcement and toughening effects but also stimulated the adhesion, proliferation, and differentiation of related osteoblasts. Furthermore, TCNCs encapsulated the CSH particles, overcoming the limitations of excessive degradation rates in bone cement and enabling sustained release of Ca2+, promoting the healing of bone defects. Overall, this study presents novel ideas and methodologies for designing bone cement with exceptional performance. It also provides a new platform for the development of bone tissue engineering and is expected to become a new type of bone regeneration material. The utilization of oceanic resources in this context holds high-value potential, alleviating environmental burdens and providing clinically applicable bone tissue repair materials with broad application prospects.

The self-regulating on cohesion properties of calcium phosphate/ calcium sulfate bone cement improved by citric acid/sodium alginate

Calcium phosphate cement (CPC) has attracted extensive interest from surgeons and materials scientists. However, the collapsibility of calcium phosphate cement limits its clinical application. In this work, a gel network of SA-CA formed by the reaction of citric acid (CA) and sodium alginate (SA) was introduced into the α-TCP/α-CSH composite. Furthermore, a high proportion of α-CSH provided more calcium sources for the system to combine with SA forming a gel network to improve the cohesion property of the composite, which also played a regulating role in the conversion of materials to HA. The morphology, physicochemical properties, and cell compatibility of the composites were studied with SA-CA as curing solution. The results show that SA-CA plays an important role in the compressive strength and collapse resistance of bone cement, and its properties can be regulated by changing the content of CA. When CA is 10 wt%, the mechanical strength is the highest, reaching 12.49 ± 2.03 MPa, which is 265.80% higher than water as the solidifying liquid. In addition, the cell experiments showed that the samples were not toxic to MC3T3 cells. The results of ALP showed that when SA-CA were used as curing solution, the activity of ALP was higher than that of blank sample, indicating that the composite bone cement could be conducive to the differentiation of osteoblasts. In this work, the α-CSH/α-TCP based composite regulated by gel network of SA-CA can provide a promising strategy to improve the cohesion of bone cement.

Composite Bone Cements with Enhanced Drug Elution.

Antibiotic-loaded bone cement (ALBC) has become an indispensable material in orthopedic surgery in recent decades, owing to the possibility of drugs delivery to the surgical site. It is applied for both infection prophylaxis (e.g., in primary joint arthroplasty) and infection treatment (e.g., in periprosthetic infection). However, the introduction of antibiotic to the polymer matrix diminishes the mechanical strength of the latter. Moreover, the majority of the loaded antibiotic remains embedded in polymer and does not participate in drug elution. Incorporation of the various additives to ALBC can help to overcome these issues. In this paper, four different natural micro/nanoscale materials (halloysite, nanocrystalline cellulose, micro- and nanofibrillated cellulose) were tested as additives to commercial Simplex P bone cement preloaded with vancomycin. The influence of all four materials on the polymerization process was comprehensively studied, including the investigation of the maximum temperature of polymerization, setting time, and monomer leaching. The introduction of the natural additives led to a considerable enhancement of drug elution and microhardness in the composite bone cements compared to ALBC. The best combination of the polymerization rate, monomer leaching, antibiotic release, and microhardness was observed for the sample containing nanofibrillated cellulose (NFC).

Mechanical and Antibacterial Properties of Bone Cement Composites Containing Silver Nanoparticles Compounded with Various Types of Chitosan

To analyze the mechanical and antibacterial properties of bone cement composites that contain silver nanoparticles (AgNPs) compounded with chitosan (CS) and carboxymethyl chitosan (CMCS). An oxidation-reduction reaction was performed under sonic oscillation to prepare ten percent wt% AgNPs, CS-AgNPs and CMCS-AgNPs, which were subsequently mixed with polymethyl methacrylate (PMMA). The compressive and bending strengths of these nanoparticles were measured before and after the samples were soaked in simulated body fluid (SBF). The Kirby-Bauer (K-B) method and flask oscillation method were used to evaluate the antibacterial effects of the composites. The compressive and bending strengths of the AgNP, CS-AgNP, and CMCS-AgNP groups were significantly improved (P < 0.001). After the AgNP, CS-AgNP, and CMCS-AgNP groups were soaked in SBF, their bending strengths were significantly higher than that of the control group (P < 0.001). The K-B test showed that only the 5 wt% and 10 wt% CMCS-AgNP groups exhibited bacteriostatic rings for Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Flask oscillation analyses revealed that the 5 wt% and 10 wt% CMCS-AgNP exhibited good bacteriostatic activity against S. aureus, but good activity against MRSA was only observed for the 10 wt% CMCS-AgNP group. We developed CS/CMCS-AgNP bone cement composites that show good mechanical properties and antibacterial activity.

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.

Clinical Outcomes After Cranioplasty With Titanium Mesh, Polyetheretherketone, or Composite Bone Cement: A Retrospective Study.

Cranioplasty is a common neurosurgical procedure; however, the optimal material choice remains controversial. At the time of this writing, autologous bone, the preferred choice for primary cranioplasty, has a high incidence of complications such as infection and resorption, thus requiring frequent use of synthetic materials. Therefore, this study aimed to compare the clinical benefits of titanium mesh (Ti), polyetheretherketone (PEEK), and composite bone cement (CBC) in cranioplasty to provide a clear selection basis for clinicians and patients. This study retrospectively collected data from 207 patients who underwent cranioplasty with Ti (n=129), PEEK (n=54), and CBC (n=24) between January 2018 and December 2020 at Henan Provincial People's Hospital. Postoperative follow-up information after 6 months was used to compare the long-term effects of the 3 materials on the patients. There were no significant differences in the overall complication rate after cranioplasty among the 3 materials. However, subcutaneous effusion was more frequent with PEEK (24.07%) and CBC (20.83%) than with Ti (2.33%). Second, there were no significant differences in the increase in Glasgow Outcome Scale and Karnofsky Performance Status scores after cranioplasty among the 3 materials. Finally, we found that PEEK had the highest patient satisfaction and hospitalization cost, whereas the opposite was true for Ti. Although the surgical outcomes of the 3 implant materials were similar, an examination of clinical outcomes such as patient satisfaction showed significant differences, deepening people's perceptions of the 3 materials.

Enhancement of mechanical and thermal properties of poly methyl methacrylate composite bone cements with zinc oxide nanostructures modified carbon fibres additives

Acrylic bone cement, which primarily consists of polymethyl methacrylate (PMMA), is widely used in orthopaedics, dentistry, and particularly in joint arthroplasty surgery. However, bone cements (BCs) have several limitations, including low mechanical properties, bioactivity issues, and high heat generation during polymerization. In recent years, there has been significant interest in studying the development of mechanical, thermal, and antibacterial properties of bone cement. In this study, ZnO nanostructures modified CFs were added to PMMA BCs at concentrations ranging from 0.10 wt% to 1.00 wt%, and the mechanical and thermal properties of the novel PMMA composite BCs were investigated. The novel composite materials were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Mechanical tests including compression and 4-point bending were performed on the composite structures, along with thermogravimetric analysis (TGA). The results revealed that the composite cement containing 0.25 wt% ZnO/CFs reinforcement agent exhibited the best mechanical properties and thermal stability. The flexural strength of the 0.25 wt% ZnO/CFs reinforced PMMA composite BCs increased by 78.9%, while the compression strength increased by 277.4% compared to the control group.

Physical, Mechanical, and Biological Properties of PMMA-Based Composite Bone Cement Containing Silver-Doped Bioactive and Antibacterial Glass Particles with Different Particles Sizes.

In the present work, antibacterial composite bone cement was designed by introducing a bioactive and antibacterial glass into a commercial formulation. The effect of glass particles' addition on the curing parameters of the polymeric matrix was evaluated; moreover, the influence of the glass particle size on the glass dispersion, compressive and bending strength, bioactivity, and antibacterial effect was estimated. The results evidence a delay in the polymerization kinetics of the composite cement, which nevertheless complies with the requirements of the ISO standard. Morphological characterization provides evidence of good dispersion of the glass in the polymeric matrix and its exposition on the cement surface. The different glass grain sizes do not affect the composites' bioactivity and compressive strength, while a slight reduction in bending strength was observed for samples containing glass powders with greater dimensions. The size of the glass particles also appears to have an effect on the antibacterial properties, since the composites containing larger glass particles do not produce an inhibition halo towards the S. aureus strain. The obtained results demonstrate that, by carefully tailoring the glass amount and size, a multifunctional device for artificial joint fixing, temporary prostheses, or spinal surgery can be obtained.

Synergistic effect of drug/antibiotic-impregnated micro/nanohybrid mesoporous bioactive glass/calcium phosphate composite bone cement on antibacterial and osteoconductive activities

Calcium phosphate bone cements (CPC) can be used in minimally invasive surgery because of their injectability, and they can also be used to repair small and irregular bone defects. This study aimed to release the antibiotic gentamicin sulfate (Genta) to reduce tissue inflammation and prevent infection in the early stages of bone recovery. Subsequently, the sustained release of the bone-promoting drug ferulic acid (FA) mimicked the response of osteoprogenitor D1 cells interaction, thereby accelerating the healing process of the overall bone repair. Accordingly, the different particle properties of micro-nano hybrid mesoporous bioactive glass (MBG), namely, micro-sized MBG (mMBG) and nano-sized MBG (nMBG), were explored separately to generate different dose releases in MBG/CPC composite bone cement. Results show that nMBG had better sustained-release ability than mMBG when impregnated with the same dose. When 10 wt% of mMBG hybrid nMBG and composite CPC were used, the amount of MBG slightly shortened the working/setting time and lowered the strength but did not hinder the biocompatibility, injectability, anti-disintegration, and phase transformation of the composite bone cement. Furthermore, compared with 2.5wt%Genta@mMBG/7.5 wt% FA@nMBG/CPC, 5wt.%Genta@mMBG/5wt.%FA@nMBG/CPC exhibited better antibacterial activity, better compressive strength, stronger mineralization of osteoprogenitor cell, and similar 14-day slow-release trend of FA. The MBG/CPC composite bone cement developed can be used in clinical surgery to achieve the synergistic sustained release of antibacterial and osteoconductive activities.

Effects of ATP on the Physicochemical Properties and Cytocompatibility of Calcium Sulfate/Calcium Citrate Composite Cement.

Adenosine triphosphate (ATP), acting as a source of energy, has effects on cellular activities, such as adhesion, proliferation, and differentiation. In this study, ATP-loaded calcium sulfate hemihydrate/calcium citrate tetrahydrate cement (ATP/CSH/CCT) was successfully prepared for the first time. The effect of different contents of ATP on the structure and physicochemical properties of ATP/CSH/CCT was also studied in detail. The results indicated that incorporating ATP into the cement did not significantly alter their structures. However, the addition ratio of ATP directly impacted the mechanical properties and in vitro degradation properties of the composite bone cement. The compressive strength of ATP/CSH/CCT gradually decreased with an increasing ATP content. The degradation rate of ATP/CSH/CCT did not significantly change at low concentrations of ATP, but it increased with a higher ATP content. The composite cement induced the deposition of a Ca-P layer in a phosphate buffer solution (PBS, pH = 7.4). Additionally, the release of ATP from the composite cement was controlled. The ATP was controlled releasing at the 0.5% and 1% ATP in cement by the diffusion of ATP and the degradation of the cement, whereas it was controlled by the diffusion process merely at the 0.1% ATP in cement. Furthermore, ATP/CSH/CCT demonstrated good cytoactivity with the addition of ATP and is expected to be used for the repair and regeneration of bone tissue.

PMMA composite bone cement containing bioactive and ferrimagnetic glass-ceramic particles: Effect of temperature and of the additional phase on some physical and mechanical properties

In this work, PMMA-based composite bone cements, embedding bioactive and ferrimagnetic glass-ceramic particles, have been prepared and characterized. Bioactivity, wettability, density, curing parameters, viscoelastic behaviour, bending strengths and creep have been investigated at 37 °C. The growth of a layer of HA on the samples surface after immersion in SBF has been confirmed. The presence of glass-ceramic particles improved the wetting behaviour of the composite cements. Shorter curing times and lower maximum temperatures for the three composite cements, in comparison to the plain one, have been detected. Almost unaffected mechanical properties of the composite bone cements have been found in comparison to those of the plain commercial cement both at room and at 37 °C. A little increase of the viscous flow has been evidenced in the composite samples at 37 °C. Radiographic imaging confirmed the intrinsic radiopacity of the composite cements.

Enhanced Cell Osteogenic Differentiation in Alendronate Acid and Flufenamic Acid Drug-Impregnated Nanoparticles of Mesoporous Bioactive Glass Composite Calcium Phosphate Bone Cement In Vitro.

This study aims to compare the anti-osteoporotic drugs alendronic acid (ALN) and flufenamic acid (FA) alone impregnate into nanoparticles of mesoporous bioactive glass (nMBG), which further composites calcium phosphate cement (CPC) and investigates their in vitro performance. The drug release, physicochemical properties, and biocompatibility of nMBG@CPC composite bone cement are tested, and the effect of the composites on improving the proliferation and differentiation efficiency of mouse precursor osteoblasts (D1 cells) is also investigated. Drug release shows that FA impregnates nMBG@CPC composite, a large amount of FA is released rapidly within 8 h, gradually reaching a stable release within 12 h, followed by a slow and sustained release within 14 days, and then reaches a plateau within 21 days. The release phenomenon confirms that the drug-impregnated nBMG@CPC composite bone cement effectively achieves slow drug delivery. The working time and setting time of each composite are within 4-10 min and 10-20 min, respectively, meeting the operational requirements of clinical applications. The addition of nMBG nanoparticles in the CPC matrix did not prevent the aggregation phenomenon under microstructural observation, thus resulting in a decrease in the strength of the nMBG@CPC composite. However, after 24 h of immersed reaction, the strength of each 5 wt.% nMBG impregnated with different concentrations of FA and ALN is still greater than 30 MPa, which is higher than the general trabecular bone strength. The drug-impregnated nMBG@CPC composites did not hinder the product formation and exhibit biocompatibility. Based on the proliferation and mineralization of D1 cells, the combination of nMBG with abundant FA and ALN in CPC is not conducive to the proliferation of D1 cells. However, when D1 cells are contact cultured for 21 days, alkaline phosphatase (ALP) enzyme activity shows higher ALP secretion from drug-impregnated nMBG@CPC composites than drug-free composites. Accordingly, this study confirms that nMBG can effectively impregnate the anti-osteoporosis drugs FA and ALN, and enhance the mineralization ability of osteoblasts. Furthermore, drug-impregnated nMBG applications can be used alone or in combination with CPC as a new option for osteoporotic bone-filling surgery.

Injectable Self-Setting Ternary Calcium-Based Bone Cement Promotes Bone Repair.

Bone defects, especially large ones, are clinically difficult to treat. The development of new bone repair materials exhibits broad application prospects in the clinical treatment of trauma. Bioceramics are considered to be one of the most promising biomaterials owing to their good biocompatibility and bone conductivity. In this study, a self-curing bone repair material having a controlled degradation rate was prepared by mixing calcium citrate, calcium hydrogen phosphate, and semi-hydrated calcium sulfate in varying proportions, and its properties were comprehensively evaluated. In vitro cell experiments and RNA sequencing showed that the composite cement activated PI3K/Akt and MAPK/Erk signaling pathways to promote osteogenesis by promoting the proliferation and osteoblastic differentiation of mesenchymal stem cells. In a rat model with femoral condyle defects, the composite bone cement showed excellent bone repair effect and promoted bone regeneration. The injectable properties of the composite cement further improved its practical applicability, and it can be applied in bone repair, especially in the repair of irregular bone defects, to achieve superior healing.

Physicochemical and biological properties of composite bone cement based on octacalcium phosphate and tricalcium silicate

Biocompatible tricalcium silicate (C3S) bone cement is widely used as dental and bone repair material; however, its long setting time, poor injectability and low initial mechanical properties limit clinical applications. In order to improve C3S silicate bone cement and its derivatives to play a more important role in tooth restoration, bone defect repair, implant coating and tissue engineering scaffolds, a novel C3S and octacalcium phosphate (OCP) composite bone cement (OCP/C3S) was prepared and evaluated for setting time, injectability, anti-flocculation, pH, microstructure, bioactivity and cytotoxicity. The setting time of the OCP/C3S composite bone cement was controlled within the clinically operable time range (8.3–13.7 min); the cement exhibited good compressive strength, injectability (93.54%), and anti-collapse performance. The 20% OCP/C3S composite bone cement had a compressive strength of 28.94 MPa, 93% stronger than pure C3S (14.98 MPa). An in vitro immersion test showed that the composite bone cement had excellent hydroxyapatite forming ability, proper degradation rate, and a low pH value. Cellular experiments confirmed the low cytotoxicity of the composite bone cement and its great capacity for cell proliferation. These results indicate that 20% OCP/C3S composite bone cement is a promising biomaterial.

Osteogenic effect of magnesium oxychloride cement modified with phytic acid and loaded with strontium ranelate

BackgroundMagnesium oxychloride cement has good mechanical properties, but poor water resistance.MethodsPhytic acid, which can form chelate with Mg2+, was used to modify magnesium oxychloride cement, and the effects of phytic acid on the strength, in vitro degradation and biological activity of magnesium oxychloride cement were studied. Based on the preparation of phytic acid modified magnesium oxychloride cement with good water resistance and biological activity, osteoporosis treatment strontium ranelate was loaded on phytic acid- magnesium oxychloride cement, strontium ranelate/phytic acid-magnesium oxychloride cement was prepared.ResultsIt was found that the compressive strength of 1.25 wt% phytic acid-magnesium oxychloride cement after soaking in SBF for 28 d could reach 40.5 ± 2.0 MPa, 13.33% higher than that of the control group (when phytic acid was 0 wt%), and the mass loss rate of all ages was lower than that of the control group. The water resistance of magnesium oxychloride cement was effectively improved by phytic acid. After loading with strontium ranelate, the water resistance of 1.25 wt% phytic acid-magnesium oxychloride cement was improved. Cell experiments showed that strontium ranelate could effectively promote cell proliferation and improve the expression of osteoblast-related proteins. When strontium ranelate/phytic acid-magnesium oxychloride cement samples were implanted subcutaneously in rats for 4 w, no obvious inflammatory response was observed, and the material was tightly bound to the surrounding tissues. When bone cement was implanted into rat femur for 4 w, the bone cement was gradually wrapped and absorbed by new bone tissue, which grew from the outside to the inside, indicating that the bone cement containing strontium ranelate/phytic acid-magnesium oxychloride cement had excellent bone-forming ability.ConclusionsIn conclusion, the results indicated that strontium ranelate/phytic acid-magnesium oxychloride cement composite bone cement had a potential application prospect in clinical bone repair.Graphical

Study on modification of hydroxyapatite/magnesium phosphate bone cement by N-acetyl-l-cysteine

Magnesium phosphate cement has good biological activity and degradation performance. However, it still has the defects of poor strength and water resistance. N-acetyl-l-cysteine has good osteogenic properties. The nano-hydroxyapatite/magnesium phosphate cement was modified by N-acetyl-l-cysteine, and the effects of N-acetyl-l-cysteine on the strength, degradation and biological activity of nano-hydroxyapatite/magnesium phosphate cement were studied. The results showed that the compressive strength of 0.5 wt% N-acetyl-l-cysteine modified nano-hydroxyapatite/magnesium phosphate cement could reach 76.1 ± 1.4 MPa after soaking in simulated body fluid for 28 days, which was 6.3% higher than that of the control group (the content of N-acetyl-l-cysteine was 0 wt%), and the softening coefficient of each age was higher than that of the control group. Cell experiments proved that N-acetyl-l-cysteine could effectively promote cell proliferation and improve the expression of osteogenic related genes and proteins. After implanting the composite bone cement into rats’ femurs for 12 weeks, the materials were gradually wrapped and absorbed, and the new bone tissue grew from outside to inside, indicating that N-acetyl-l-cysteine bone cement had an good ability to promote bone formation. Therefore, the composite bone cement of this study has potential application prospects in clinical bone repair.

The effect of tricalcium silicate incorporation on bioactivity, injectability, and mechanical properties of calcium sulfate/bioactive glass bone cement

The conventional Polymethyl methacrylate (PMMA) bone cement is not biodegradable and not bioactive to bond with the native bone and causes tissue necrosis resulting from its high exothermic polymerization. Hence, biodegradable bioactive bone cements with suitable setting time and mechanical properties should be introduced. In this study, novel bioactive bone cements containing Calcium Sulfate Hemihydrate (CSH), Bioactive Glass (BG), and Tricalcium Silicate (TSC) were developed. Firstly, CSH and BG binary system was optimized based on preliminary setting and mechanical tests. Secondly, the composite bioactive bone cements were obtained by adding different quantities of TCS to the optimized CS-BG (1.3:1 wt % ratio) system. All groups exhibited desirable handling properties, an initial setting time of lower than 15 min, injectability of greater than 85%, and controlled degradability. Moreover, they demonstrated initial compressive strength values of higher than 12 MPa, superior to trabecular bone. After 28 days of hydration, the compressive strength of the cement containing 30% TCS reached 51.04 MPa. Furthermore, the present bone cements showed favorable bioactivity and bone-bonding ability as a result of calcium carbonate and hydroxyapatite (HA) formation. Furthermore, this novel bone cement exhibited appropriate biocompatibility and mesenchymal stem cell attachment, suggesting its potential for clinical applications.

Composite monetite/amorphous calcium phosphate bone cement promotes bone regeneration

Monetite (MC) is a type of calcium phosphate cement (CPC). It has various morphologies, continuous degradation and absorption properties; however, its high porosity will affect its mechanical properties. There is minimal research on MC is immature. Amorphous calcium phosphate (ACP) is widely used and exhibits good biocompatibility; however, it is unstable. In this study, MC was combined with ACP at different weight ratios to form new types of bone cements. The mechanical properties, biocompatibility, and inductive ability for osteogenesis and osteoclasts of different MC/ACP composite bone cements were evaluated. The biocompatibility and effects on osteogenic and osteoclast differentiation of MC/ACP composite bone cements were investigated in vitro using mouse bone marrow mesenchymal stem cells (mBMMSCs) and mouse monocyte/macrophage cell line RAW 264.7. RAW 264.7 cells can differentiate into osteoclasts by osteoclast differentiation. The results indicated that the overall performance of the MC/ACP composite bone cement was better than that of the MC or ACP alone. Compared to the other groups, the biocompatibility of MC75 (75 wt% MC and 25 wt% ACP) was optimal; it was able to induce mBMMSCs osteogenesis to a greater extent. MC75 was the least favorable for the proliferation, migration, and differentiation of osteoclasts. The mechanical properties, setting time and injectability of MC75 meet clinical application requirements. This study demonstrated that MC75 is a promising bone cement for repairing bone defects.