Brushite Cement Research Articles

New Insights Into Application Relevant Properties of Cu2+-Doped Brushite Cements.

Doping of brushite cements with metal ions can entail many positive effects on biological and physicochemical properties. Cu2+ ions are known to exhibit antibacterial properties and can additionally have different positive effects on cells as trace elements, whereas high Cu2+ concentrations are cytotoxic. For therapeutical applications of bone cement, a combination of good biocompatibility and sufficient mechanical properties is required. Therefore, the aim of this study was to investigate different physicochemical and biological aspects, relevant for application, of a brushite cement with Cu2+-doped β-tricalcium phosphate, monocalcium phosphate monohydrate and phytic acid as setting retarder. Additionally, the ion release was compared with a cement with citric acid as setting retarder. The investigated cements showed good injectability coefficients, as well as compressive strength values sufficient for application. Furthermore, no antibacterial effects were detected irrespective of the Cu2+ concentration or the bacterial strain. The cell experiments with eluate samples showed that the viability of MC3T3-E1 cells tended to decrease with increasing Cu2+ concentration in the cement. It is suggested that these biological responses are caused by the difference in the Cu2+ release from the hardened cement depending on the solvent medium. Furthermore, the cements showed a steady release of Cu2+ ions to a lesser extent in comparison with a cement with citric acid as setting retarder, where a burst release of Cu2+ was observed. In conclusion, despite the anticipated antibacterial effect of Cu2+-doped cements was lacking and mammalian cell viability was slightly affected, Cu2+-concentrations maintained the physicochemical properties as well as the compressive strength of cements and the slow ion release from cements produced with phytic acid is considered advantageous compared to citric acid-based formulations.

Biological and mechanical performance of calcium phosphate cements modified with phytic acid

Calcium phosphate cements, primarily brushite cements, require the addition of setting retarders to ensure adequate processing time and processability. So far, citric acid has been the primary setting retarder used in this context. Due to the poor biocompatibility, it is crucial to explore alternative options for better processing. In recent years, the setting retarder phytic acid (IP6) has been increasingly investigated. This study investigates the biological behaviour of calcium phosphate cements with varying concentrations of IP6, in addition to their physical properties. Therefore cytocompatibility in vitro testing was performed using osteoblastic (MG-63) and osteoclastic (RAW 264.7 differentiated with RANKL) cells. We could demonstrate that the physical properties like the compressive strength of specimens formed with IP6 (brushite_IP6_5 = 11.2 MPa) were improved compared to the reference (brushite = 9.8 MPa). In osteoblast and osteoclast assays, IP6 exhibited significantly better cytocompatibility in terms of cell activity and cell number for brushite cements up to 11 times compared to the brushite reference. In contrast, the calcium-deficient hydroxyapatite (CDHA) cements produced similar results for IP6 (CDHA_IP6_0.25 = 27.0 MPa) when compared to their reference (CDHA = 21.2 MPa). Interestingly, lower doses of IP6 were found to be more effective than higher doses with up to 3 times higher. Additionally, IP6 significantly increased degradation in both passive and active resorption. For these reasons, IP6 is emerging as a strong new competitor to established setting retarders such as citric acid. These cements have potential applications in bone augmentation, the stabilisation of non-load bearing fractures (craniofacial), or the cementation of metal implants.Graphical

Magnesium-Substituted Brushite Cement: Physical and Mechanical Properties

Brushite cements (BrCs) are calcium phosphate-based materials that are being widely used in hard tissue engineering applications due to their osteoconductivity, injectability, and bioresorbability. Therefore, the goal was to evaluate the effects of Mg concentration on the phase composition, setting time, and strength of BrC. Mg, which plays a vital role in bodily functions and bone health, was added to BrC at concentrations of 0.25, 0.50, 1.00, 1.50, 2.00, and 2.50 wt.%. The results showed that Mg stabilizes the TCP structure and increases the TCP content in final BrC. The initial and final setting times of BrCs increase with higher concentrations of Mg. Although 0.25 wt.% Mg did not change the setting of BrCs significantly, a higher concentration of 1.00 wt.% increased the initial setting time from 4.87 ± 0.38 min to 15.14 ± 0.88 min. Cements with Mg concentrations of 1.5 wt.% and above did not set after 4 h. Mg addition up to 0.5 wt.% did not change the compressive strength; however, higher concentrations decreased it significantly and 2.5 Mg-BrC had the lowest strength of 0.45 ± 0.09 MPs. Together, our results show that Mg can be added up to 1.00 wt.% without any adverse effect on the physical and mechanical properties of BrC.

Anatomical design and production of a novel three-dimensional co-culture system replicating the human flexor digitorum profundus enthesis.

The enthesis, the specialized junction between tendon and bone, is a common site of injury. Although notoriously difficult to repair, advances in interfacial tissue engineering techniques are being developed for restorative function. Most notably are 3D invitro co-culture models, built to recreate the complex heterogeneity of the native enthesis. While cell and matrix properties are often considered, there has been little attention given to native enthesis anatomical morphometrics and replicating these to enhance clinical relevance. This study focuses on the flexor digitorum profundus (FDP) tendon enthesis and, by combining anatomical morphometrics with computer-aided design, demonstrates the design and construction of an accurate and scalable model of the FDP enthesis. Bespoke 3D-printed mould inserts were fabricated based on the size, shape and insertion angle of the FDP enthesis. Then, silicone culture moulds were created, enabling the production of bespoke anatomical culture zones for an invitro FDP enthesis model. The validity of the model has been confirmed using brushite cement scaffolds seeded with osteoblasts (bone) and fibrin hydrogel scaffolds seeded with fibroblasts (tendon) in individual studies with cells from either human or rat origin. This novel approach allows a bespoke anatomical design for enthesis repair and should be applied to future studies in this area.

Брушитовый бор-содержащий цемент с антибактериальными свойствами

Boron-containing brushite cements (B-BC) for bone grafting based on B-substituted β-tricalcium phosphate (B-TCP) have been developed. The phase composition and microstructure of B-BC have been studied. It is shown that the crystalline phase of brushite is formed as a result of hardening of cements. The behavior of B-BC in physiological solution containing TRIS-buffer was studied. The strength of B-BC under compression 5 days after mixing is 22.5 ± 1 MPa. Studies of antibacterial activity against gram-negative strain E. coli ATCC25922 and gram-positive strain S. aureus ATCC25923 showed that boron containing brushite cement exhibits antibacterial activity against both strains, causing a decrease in the number of CFU after 3 h of incubation. In vitro studies of the developed B-BC were carried out, it was shown that the developed cements based on TCP and B-TCP are biocompatible and promising for use in bone tissue surgery.

Novel waste bone recovery system for CO2 and SOx utilization in cement plants using microbubble carbonation reactor

Cement has been widely used as a primary building material to construct various types of infrastructure. However, cement plants emit excessive carbon dioxide (CO2) and sulfur oxide (SOx) during calcination of limestone. Animal bone residues can reduce air pollutants as they contain calcium hydroxyapatite (Ca10(PO4)6(OH)2), which can capture and utilize CO2 and SOx. Therefore, brushite cement (CaHPO4∙2 H2O) and raw materials of cement, such as calcium carbonate (CaCO3) and calcium sulfate (CaSO4), can be recovered. In this study, a novel waste bone recovery system for CO2 and SOx utilization using cement plant flue gas was developed using a microbubble carbonation reactor (MCR). The system was designed using a process simulation model with the experimental results of the proposed MCR. Using an MCR with a high carbonation rate increases economic feasibility by decreasing the capacity of the conventional cost-intensive carbonation process. The proposed model involves the following steps: (1) waste bone dissolution and synthesis of CaHPO4∙2 H2O; (2) SOx capture and utilization; (3) CO2 capture and utilization using MCR. The total annualized cost (TAC) was determined to validate the economic feasibility of the system. Consequently, 99% of SOx and 94% of CO2 were captured using the production of CaSO4 and CaCO3 at the MCR, respectively. Additionally, the TAC of the proposed system can be decreased by 44% and 27% compared to the base cases 1 and 2 corresponding to the conventional SOx and CO2 capture processes.

Antibacterial Composite Material Based on Polyhydroxybutyrate and Zn-Doped Brushite Cement.

A composite material based on electrospinning printed polyhydroxybutyrate fibers impregnated with brushite cement containing Zn substitution was developed for bone implant applications. Powder X-ray Diffraction (PXRD), Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy were applied for materials characterization. Soaking the composite in Ringer's solution led to the transformation of brushite into apatite phase, accompanied by the morphology changes of the material. The bending strength of the composite material was measured to be 3.1 ± 0.5 MPa. NCTC mouse fibroblast cells were used to demonstrate by means of the MTT test that the developed material was not cytotoxic. The behavior of the human dental pulp stem cells on the surface of the composite material investigated by the direct contact method was similar to the control. It was found that the developed Zn containing composite material possessed antibacterial properties, as testified by microbiology investigations against bacteria strains of Escherichia coli and Staphylococcus aureus. Thus, the developed composite material is promising for the treatment of damaged tissues with bacterial infection complications.

COMPARISON OF BONE ANCHOR MATERIALS IN AN ANATOMICALLY RELEVANT IN VITRO MODEL OF THE BONE-TENDON INTERFACE

To ensure clinical relevance, the in vitro engineering of tissues for implantation requires artificial replacements to possess properties similar to native anatomy. Our overarching study is focussed on developing a bespoke bone-tendon in vitro model replicating the anatomy at the flexor digitorum profundus (FDP) tendon insertion site at the distal phalanx. Anatomical morphometric analysis has guided FDP tendon model design consisting of hard and soft tissue types. Here, we investigate potential materials for creation of the model's bone portion by comparison of two bone cements; brushite and genex (Biocomposites Ltd).3D printed molds were prepared based on anatomical morphometric analysis of the FDP tendon insertion site and used to cast identical bone blocks from brushite and genex cements. Studies assessing the suitability of each cement type were conducted e.g. setting times, pH on submersion in culture medium and interaction with fibrin gels. Data was collected using qualitative imaging and qualitative measurements (N=3,n=6) for experimental conditions.Both brushite (BC) and genex (GC) cements could be cast into bespoke molds, producing individual blocks and were mixed/handled with appropriate setting times. On initial submersion in culture medium, BC caused a reduction in pH values (7.49 [control]) to 6.85) while GC remained stable (7.59). Reduction in pH value also affected fibrin gel interaction where gel was seen to be detaching/not forming around BC and medium discolouration was noted. This was not observed in GC. While GC outperformed BC in initial tests, repeated washing of BC led to pH stabilisation (7.5,3xwashes), consistent with their further use in this model.This study has compared BC and GC as materials for bone block production. Both materials show promise, and current work assessing material properties and cell proliferation are needed to inform our choice for use in our FDP-tendon-bone interface model.This research was supported by an ORUK Studentship award (ref:533). Genex was kindly provided by Biocomposites, Ltd.

Preparation and characterizations of an injectable and biodegradable high-strength iron-bearing brushite cement for bone repair and vertebral augmentation applications.

Brushite cements have good osteoconductive and resorbable properties, but the low mechanical strength and poor injectability limit their clinical applications in load-bearing conditions and minimally invasive surgery. In this study, an injectable brushite cement that contains monocalcium phosphate monohydrate (MCPM) and β-tricalcium phosphate (β-TCP) as its solid phase and ammonium ferric citrate (AFC) solution as the aqueous medium was designed to have high mechanical strength. The optimized formulation achieved a compressive strength of 62.8 ± 7.2 MPa, which is above the previously reported values of hand-mixing brushite cements. The incorporation of AFC prolonged the setting times and greatly enhanced the injectability and degradation properties of the cements. In vitro and in vivo experiments demonstrated that the brushite cements exhibited good biocompatibility and bone regeneration capacity. The novel brushite cement is promising for bone healing in load-bearing applications.

The effect of Cu2+ doping in β-tricalcium phosphate on the hydration mechanism of a brushite cement

Brushite cements show excellent biocompatibility and are therefore an often-used material for bone repair. However, methods to prevent inflammations after surgery are needed. As Cu2+ was proven to provide antibacterial properties, as well as other application relevant features, it is a promising additive. Concerning these factors, a brushite cement containing Cu2+-doped β-tricalcium phosphate, monocalcium phosphate monohydrate, and phytic acid as setting retarder was investigated with powder and in situ X-ray diffraction, isothermal heat flow calorimetry, in situ 1H-time domain – nuclear magnet resonance, and pore solution analysis. The influence of Cu2+ ions on the hydration kinetics of the brushite cement and the locations of the Cu2+ ions after completion of the hydration were the main questions of interest. Heat flow calorimetry showed a significant retardation and deceleration of the hydration with increasing Cu2+ content in β-tricalcium phosphate. This effect can be directly correlated to the Cu2+ ions, as it was also shown for cements without phytic acid. X-ray diffraction showed brushite as main hydrate phase. Additionally, Cu2+-doped cements formed a hydrate phase not assignable by X-ray diffraction, which is assumed to be Cu2+ containing. Furthermore, Cu2+ was detected in the pore solution after the hydration, and no signs of Cu2+ incorporation in the crystal structure of brushite were found.

In vivo biocompatibility of SrO and MgO doped brushite cements.

The addition of dopants in biomaterials has emerged as a critical regulator of bone formation and regeneration due to their imminent role in the biological process. The present work evaluated the role of strontium (Sr) and magnesium (Mg) dopants in brushite cement (BrC) on in vivo bone healing performance in a rabbit model. Pure, 1wt% SrO (Sr-BrC), 1wt% MgO (Mg-BrC), and a binary composition of 1.0wt% SrO + 1.0wt% MgO (Sr + Mg-BrC) BrCs were implanted into critical-sized tibial defects in rabbits for up to 4months. The in vivo bone healing of three doped and pure BrC samples was examined and compared using sequential radiological examination, histological evaluations, and fluorochrome labeling studies. The results indicated excellent osseous tissue formation for Sr-BrC and Sr + Mg-BrC and moderate bone regeneration for Mg-BrC compared to pure BrC. Our findings indicated that adding small amounts of SrO, MgO, and binary dopants to the BrC can significantly influence new bone formation for bone tissue engineering.

دراسات بيوفيزيقية للمحاكاة البيلوجية لإسمنت العظام مع الألجينات لاستخدامه في المجال الطبي

Osteoporosis and many other bone defects are described as the diseases that have attracted attention in the past two decades over worldwide. Because of it is known as a silent disease and with a high commonness rate among the elderly, the battle could be difficult. This paper aims to assess the impact of the inclusion of some additions to the brushite cement and use fluid simulation in the body that contain calcium and free of protein in the laboratory as a stimulant for the apatite formed such as bone apatite samples consisting of brushite cement and various elements that have been added to the roofs. The research paper adopted the experimental approach. The stable phases of calcium phosphate cements depend significantly upon temperatures and the presence of water, either during processing or in the use situation. At body temperature, only two calcium phosphates are stable when in interaction with aqueous media such as body fluids. The samples under investigation are used to select samples which can be considered suitable as a biomaterial in vitro. The samples prepared in the form of two samples each one regards with a group of additives including sodium Alginate, Wollastonite, Titanium Oxide, Hydroxyapatite and Zinc Oxide. Soaking brushite samples with their additives in simulated body fluid for one week may cause presence of a bone-like apatite layer phase (Ca10(OH)2(PO4)6, HA) on the surface of these samples. To sustain the aim of the study, the samples studied by using the X-ray diffraction spectra, scanning electron microscope and Raman spectroscopy. The X-ray diffraction used to ensure the presence of the components used in the preparation of the samples is present in the samples or not. The study of X-ray examination for the samples under investigation after soaking for one week in SBF to help us to recognize new phases appearing after the interaction between the samples surfaces and the components of the SBF.

Fabrication and characterization of cellulose nano crystal and soya modified injectable brushite bone cement for enhanced bone regeneration

An inventive, cellulose nano crystal (CNC) and isolated soya flour (SPI) laden brushite-based injectable bone substitute (IBS) material has been developed in the present research. The purpose of the study was to discover the physical, mechanical, in-vitro biological, and in-vivo bone forming ability of the prepared IBS. The incomparable abilities of CNC together with SPI resulted in enhanced biocompatibility, mechanical strength, and biodegradability, which together with its exclusive properties, sort it ideal for bone restoration. The CNC/SPI laden composites showed suitable mechanical strength of ~10.5 MPa for BM23 composite. The in- vitro cytocompatibility of the prepared samples were evaluated by osteoblast type MC3T3-E1 cells via MTT assay. Protein absorption and mineralization behavior of BRCNC2.0 was around (1.7 and 2.3)-fold higher than that of BR, respectively. In vivo performance was also found appreciable with ~(31.33 ± 2.04) % BV/TV. Incorporation of SPI resulted in enhanced bone formation at the central zone of the defect, while unmodified samples resulted in bone formation only at the peripheral zone. The findings of the current study proposed that CNC/SPI laden, brushite based injectable bone substitute might be proficient for bone regeneration ability.

Brushite bone cement containing polyethylene glycol for bone regeneration.

Bone cements aid in bone regeneration; however, if the handling time is not well established for the material to harden, complications may arise. This work investigates the effect of using polyethylene glycol (PEG) and characterize it in brushite bone cement in order to obtain desirable handling times as well as its regeneration invivo to analyse if addition of this polymer may significantly modify its properties. PEG 4000 was synthesised with wollastonite by phosphorization reaction in order to form brushite which was further cured by oven drying. They were further characterised and tested invivo as tibial bone defect model using rabbits. Addition of PEG exhibited handling times of 60min with a low increase in temperature when curing. Brushite phase of ∼71% was obtained after cement hardening with good compressive strength (25MPa) and decent values of porosity (33%). Invivo presented that, at 40 days postoperatively, accelerated bone neoformation with partial consolidation at 30 days and total after 60 days when using bone cement. Addition of PEG does not disrupt the beneficial properties of the bone cement and can be a potential alternative to control the time-temperature profile of hardening these materials.

Enhancement of mechanical properties and mineralization capacity of brushite cement by doping with polydopamine nanospheres

The ideal material for bone defect requires promising bioactivity and matching mechanical properties. In this study, uniform polydopamine (PDA) nanospheres were prepared by a simple and effective process and doped into the β-tricalcium phosphate (β-TCP)/ Calcium phosphate dibasic (MCPA)-based bone cement. The results revealed that the hydroxyapatite (HA) phase appeared in the cement compositions after adding 1.5 wt% of PDA nanospheres. In addition, the most striking observation was that the micro-nano-filling effect of PDA nanospheres and lath-like HA on the internal pores of cement significantly increased the compressive strength to more than twice. Moreover, the apatite mineralization capacity of 5 wt% PDA-doped nanospheres was considerably superior to that of undoped cement, and the mechanism of enhanced mineralization properties of PDA nanospheres was proposed. Hence, it is suggested that the mechanical properties and bioactivity of the cement can effectively improve with the incorporation of PDA nanospheres.

Synergetic reinforcement of brushite cements by monetite/apatite whisker-like fibers and carboxymethylcellulose

Brushite-forming cements have attracted significant interest in bone tissue engineering due to their biocompatibility, resorbability, bioactivity, osteoconductivity, and self-setting characteristics. However, their poor mechanical properties and shorter setting time in comparison to apatite cements limit their clinical applications. The aim of this study was to develop a novel calcium phosphate (CaP) fiber-carboxymethylcellulose (CMC)-brushite composite with enhanced properties, and to investigate the effect of CaP fibers and CMC on the physicochemical, mechanical, and cellular properties. Biphasic monetite/hydroxyapatite fibers were synthesized by homogenous precipitation method and added to brushite and brushite-CMC composites (5, 10 or 20 wt.%). Characterization by XRD, FTIR, and SEM confirmed the formation of brushite crystals in all the samples and revealed that CaP fibers were covered with CMC and bonded to the matrix. The addition of CaP fibers decreased the initial and final setting time. The addition of CMC resulted in a rapid initial setting time but significantly prolonged the final setting time. The incorporation of biphasic CaP fibers increased the diametral tensile strength (DTS) by up to 1.85 MPa (an increase of 105%). The incorporation of CMC both increased the DTS by up to 3.29 MPa (an increase of 165%). Both CaP fibers and CMC have no adverse biological properties. The results showed that both CaP fibers and CMC can be effective additives to control the setting reaction and improve the mechanical and cellular properties of brushite cements.

Osteogenic lithium-doped brushite cements for bone regeneration

This study investigated the osteogenic performance of new brushite cements obtained from Li+-doped β-tricalcium phosphate as a promising strategy for bone regeneration. Lithium (Li+) is a promising trace element to encourage the migration and proliferation of adipose-derived stem cells (hASCs) and the osteogenic differentiation-related gene expression, essential for osteogenesis. In-situ X-ray diffraction (XRD) and in-situ1H nuclear magnetic resonance (1H NMR) measurements proved the precipitation of brushite, as main phase, and monetite, indicating that Li+ favored the formation of monetite under certain conditions. Li+ was detected in the remaining pore solution in significant amounts after the completion of hydration. Isothermal calorimetry results showed an accelerating effect of Li+, especially for low concentration of the setting retarder (phytic acid). A decrease of initial and final setting times with increasing amount of Li+ was detected and setting times could be well adjusted by varying the setting retarder concentration. The cements presented compressive mechanical strength within the ranges reported for cancellous bone. In vitro assays using hASCs showed normal metabolic and proliferative levels. The immunodetection and gene expression profile of osteogenic-related markers highlight the incorporation of Li+ for increasing the in vivo bone density. The osteogenic potential of Li-doped brushite cements may be recommended for further research on bone defect repair strategies.

Evaluation of several conditioning matrices for the management of radioactive metal beryllium wastes

Beryllium wastes are produced by nuclear industry. One way to manage them is their encapsulation in cements. The main risk of this conditioning is the aqueous corrosion, which leads to the hydrogen production and cracks causing a loss of radioactivity confinement. The corrosion can be limited by the formation of the hydroxide solid phase Be(OH)2(s). The stability domain of this phase was calculated in water as a function of the pH: M. Pourbaix has calculated a stability domain from 2.9 to 11.7 for a 10−4 M beryllium concentration, while according to our calculation with more recent thermodynamic data, it is stable from 5.3 to 13.5. Based on Pourbaix results, beryllium cannot be conditioned in the mainly used cement for nuclear waste, Portland cement, while it is possible according to our calculations. Experimental measurements were achieved to select the data set most in agreement with the experimental observations. The beryllium reactivity has been examined in matrices having different pH pore solution: brushite cement (pH 1.75–6.44), magnesium phosphate cement (pH 5.6–8.4), calcium-sulfoaluminate cement (pH 10.9–12.3), Portland cement (pH 12.5–12.9) cements and activated slag (pH 12.9–13.8), by measuring the open circuit potential and by electrochemical impedance spectroscopy. The experimental results agree with the more recent thermodynamic data. Beryllium corrosion is too high in the brushite cement, leading to a high hydrogen production. This matrix can then not be envisaged for the conditioning of Be waste. If the beryllium is encapsulated in the activated slag, the highly alkalinity is too high in the early age, leading to a high aqueous corrosion. Activated slag are also not suitable for Be conditioning. The main conclusion of this paper is that beryllium can be encapsulated in safe conditions in Portland, magnesium phosphate and calcium sulfoaluminate cements.

Transformation kinetics of potassium and magnesium modified high-performance brushite cement to carbonated apatite in blood-mimicked condition

As a starting cement material, brushite is beneficial due to its short setting time and fast resorbability, and is metastable, allowing in vivo and in vitro transformation into a more stable calcium phosphate (CaP) phase. The challenges for a successful application of brushite include tissue inflammation from its acidic nature, and poor mechanical strength from weakly compacted crystals. Thus, in this study, it is aimed to avoid these drawbacks through a chemical modification of brushite cement. To circumvent tissue inflammation, brushite was modified with 5% of K+ or Mg2+ to induce the transformation into a more stable phase like hydroxyapatite (HAp). Surface transformation in a Tas-stimulated body fluid (Tas-SBF) solution occurred faster for K+-modified cements (1 week, to HAp and β-TCP) than for unmodified brushite (2 weeks, to HAp), and Mg2+-modified brushite (2 weeks, to HAp and β-TCP). Bulk transformation depended on the penetration of the Tas-SBF solution. Thus, Mg2+-substituted cement exhibited the most apatitic structure (26 wt%) due to the highest porosity. To improve the mechanical properties of brushite, setting retardants (acid pyrophosphate, citric acid) and an excess amount of β-TCP as a filler material were included in the cement’s composition. Diametral tensile strength (DTS) was the highest for unsubstituted cements (4.96 ± 1.04 MPa), slightly lower for K+-enriched cement (4.01 ± 0.71 MPa), and lowest for Mg2+-doped cements (1.34 ± 0.23 MPa). This study shows that it is possible to induce the transformation of brushite cement into a more biocompatible bone-like cement and simultaneously achieve enhanced mechanical properties through compositional modification of the cement.

Synthesis of brushite/polyethylene glycol cement for filler in bone tissue injuries

The objective of this work was to produce brushite cement for orthopedic applications, based on the system wollastonite/phosphoric acid with the incorporation of polyethylene glycol (PEG) as a setting and processing additive. Brushite/PEG cement was obtained by the dissolution-precipitation method and its physicochemical properties were characterized by X-ray diffraction, compressive strength, porosimetry, and biological behavior (cell adhesion and bioactivity tests). The results indicated the formation of brushite cement with 21.4 MPa of compressive strength and 30% porosity, similar to human trabecular bone. The surface was shown to be adequate for cell adhesion and growth and bioactive with the formation of apatite layers. The incorporation of PEG improved working conditions without causing undesirable changes in the physicochemical properties and biological behavior of developed cement, thus promising for the repair of bone tissue injuries.