Bone Cement Formulations Research Articles

Enhancing orthopedic outcomes: A comparative analysis of gentamicin sulphate and nanosilver in bone cement

BackgroundOrthopedic surgeries frequently utilize bone cement, which can increase the risk of postoperative infections. Addressing this challenge, this study aims to enhance the mechanical, physical, and handling properties of bone cement by integrating gentamicin sulfate (GS) and nanosilver (nAg). The objective is to evaluate and compare the effects of these additives on properties such as compressive strength, flexural strength, doughing time, working time, setting time, and exothermic temperature. By doing so, the study seeks to identify a safer and more effective alternative to traditional antibiotics in bone cement formulations, thereby improving clinical outcomes in orthopedic procedures. MethodsThis research involved a comparative analysis of modified cements against standard cements, focusing on compressive strength, flexural strength, doughing time, working time, setting time, and exothermic temperature. Various bone cement samples with GS and nAg additives were prepared and tested in accordance with international standards (ISO 5833:2002 and ASTM F451). Statistical analysis, including one-way and two-way ANOVA tests, was used to assess the significance of the results. ResultsnAg-loaded cements exhibit mechanical and physical properties on par with or supe-rior to those of GS-loaded and standard cements. Notably, nAg incorporation leads to significantly lower exothermic temperatures, reducing the risk of thermal bone tissue damage. This finding highlights that nAg-loaded cement is a safer alternative. Alongside unaltered or enhanced strength, nAgs demonstrate promise for orthopedic applications, particularly in primary arthroplasty. Additionally, nAgs reduce doughing time, enhancing the practicality of these methods in surgical settings. ConclusionsIn conclusion, this study underscores the potential advantages of incorporating GSs and nAgs into bone cement. nAg-loaded cement offers improved properties and reduced infection risk, making it a valuable choice for orthopedic procedures. It enhances both mechanical performance and safety, addressing crucial concerns in orthopedic surgery.

Finite element analysis of vertebroplasty in the osteoporotic T11-L1 vertebral body: Effects of bone cement formulation.

Vertebral compression fractures are one of the most severe clinical consequences of osteoporosis and the most common fragility fracture afflicting 570 and 1070 out of 100,000 men and women worldwide, respectively. Vertebroplasty (VP), a minimally invasive surgical procedure that involves the percutaneous injection of bone cement, is one of the most efficacious methods to stabilise osteoporotic vertebral compression fractures. However, postoperative fracture has been observed in up to 30% of patients following VP. Therefore, this study aims to investigate the effect of different injectable bone cement formulations on the stress distribution within the vertebrae and intervertebral discs due to VP and consequently recommend the optimal cement formulation. To achieve this, a 3D finite element (FE) model of the T11-L1 vertebral body was developed from computed tomography scan data of the spine. Osteoporotic bone was modeled by reducing the Young's modulus by 20% in the cortical bone and 74% in cancellous bone. The FE model was subjected to different physiological movements, such as extension, flexion, bending, and compression. The osteoporotic model caused a reduction in the average von Mises stress compared with the normal model in the T12 cancellous bone and an increment in the average von Mises stress value at the T12 cortical bone. The effects of VP using different formulations of a novel injectable bone cement were modeled by replacing a region of T12 cancellous bone with the materials. Due to the injection of the bone cement at the T12 vertebra, the average von Mises stresses on cancellous bone increased and slightly decreased on the cortical bone under all loading conditions. The novel class of bone cements investigated herein demonstrated an effective restoration of stress distribution to physiological levels within treated vertebrae, which could offer a potential superior alternative for VP surgery as their anti-osteoclastogenic properties could further enhance the appeal of their fracture treatment and may contribute to improved patient recovery and long-term well-being.

Preparation and Characterization of Mono- and Biphasic Ca1-xAgxHPO4·nH2O Compounds for Biomedical Applications.

This study aimed to explore the effects of the full-scale replacement (up to 100%) of Ca2+ ions with Ag1+ ions in the structure of brushite (CaHPO4·2H2O). This substitution has potential benefits for producing monophasic and biphasic Ca1-xAgxHPO4·nH2O compounds. To prepare the starting solutions, (NH4)2HPO4, Ca(NO3)2·4H2O, and AgNO3 at different concentrations were used. The results showed that when the Ag/Ca molar ratio was below 0.25, partial substitution of Ca with Ag reduced the size of the unit cell of brushite. As the Ag/Ca molar ratio increased to 4, a compound with both monoclinic CaHPO4·2H2O and cubic nanostructured Ag3PO4 phases formed. There was a nearly linear relationship between the Ag ion ratio in the starting solutions and the wt% precipitation of the Ag3PO4 phase in the resulting compound. Moreover, when the Ag/Ca molar ratio exceeded 4, a single-phase Ag3PO4 compound formed. Hence, adjusting the Ag/Ca ratio in the starting solution allows the production of biomaterials with customized properties. In summary, this study introduces a novel synthesis method for the mono- and biphasic Ca1-xAgxHPO4·nH2O compounds brushite and silver phosphate. The preparation of these phases in a one-pot synthesis with controlled phase composition resulted in the enhancement of existing bone cement formulations by allowing better mixing of the starting ingredients.

Influence of chitosan and chitosan oligosaccharide on dual antibiotic-loaded bone cement: In vitro evaluations.

The purpose of this study was to investigate the effect of incorporating chitosan (Ch) and chitosan oligosaccharides (ChO) into the commercially premixed antibiotic-loaded bone cement (ALBC). We compare antibiotic release profiles, antibacterial activity, and mechanical properties among different ALBC formulations. The hypothesis was that increasing the amount of Ch and ChO in the cement mixture would increase the antibiotics released and bacterial control. ALBC mixed with Ch or ChO may create a greater effect due to its superior dissolving property. The bone cement samples used in this project were made from Copal® G+V composed of vancomycin and gentamicin. To prepare the Ch and the ChO mixed bone cement samples, different amounts of Ch and ChO were added to the polymethylmethacrylate matrix with three concentrations (1%, 5%, and 10%). Drug elution assay, antimicrobial assay, in vitro cytotoxicity, and mechanical properties were conducted. Bone cement samples made from Copal® G+V alone or combined with Ch or ChO can release vancomycin and gentamicin into the phosphate-buffered saline. Mixing ChO into the bone cements can increase the amount of drug released more than Ch. ChO 10% gave the highest amount of antibiotics released. All samples showed good antibacterial properties with good biocompatibility in vitro. The microhardness values of the Ch and ChO groups increased significantly compared to the control group. In all groups tested, the microhardness of bone cements was reduced after the drug eluted out. However, this reduction of the Ch and ChO groups was in line with the control. Various attempts have been made to improve the ALBC efficacy. In our study, the best bone cement formulation was bone cement mixed with ChO (10%), which had the highest drug release profiles, was biocompatible, and contained antibacterial properties with acceptable mechanical properties. This phenomenon could result from the superior water solubility of the ChO. When ChO leaves the bone cement specimens, it generates pores that could act as a path that exposes the bone cement matrix to the surrounding medium, increasing antibiotic elution. From all above, ChO is a promising substance that could be added to ALBC in order to increase the drug elution rate. However, more in vitro and in vivo experiments are needed before being used in the clinic.

Morphology, Crystal Size and Crystallinity Degree of Silica-Calcium Phosphate Composite (S) and Apatite Cement Formulation - <i>In Vitro</i> Bioactivity Test

Silica-calcium phosphate nanocomposite (SCPC) is a porous bioactive resorbable bioactive ceramics. Incorporating apatite bone cement (AC) formulation of tetracalcium phosphate-dicalcium phosphate dihydrate and SCPC has contributed to the higher mechanical strength of a new prototype apatite cement formulation. This in-vitro experiment aims to investigate the bioactivity of AC formulation using simulated body fluid (SBF). The samples consist of two groups of AC formulations (n=4). The first group, AC with 10% SCPC and the second group AC without SCPC, was immersed in the SBF for 14 days. The samples before and after immersion were analyzed by X-Ray Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDS), and Scanning Electron Microscope (SEM). The samples' size and degree of crystallinity were analyzed statistically using Shapiro-Wilk, Levene, and Mann-Whitney test. As a result, there was no significant difference in the crystal size and the degree of the crystallinity of both samples. The surface morphology of all samples were coated with hydroxyapatite after immersing in the SBF solution. Both AC formulations with and without SCPC have bioactivity as the bone substitute materials. Combining AC with SCPC50 is a promising method to improve the bioactivity and mechanical strength of calcium phosphate bone cement.

Engineered bone cement trigger bone defect regeneration

Bone defects, which can be caused by factors such as trauma, tumor, or osteomyelitis, are clinically common. They lessen the weight a bone is able to bear and cause severe pain to the patient. Although bone transplantation is the gold standard for treating bone defects, it is not suitable for all patients due to its poor availability, risk of spreading disease, and possibility of requiring a secondary surgery. Bone cement as a filler for bone defects can fill any shape of bone defect, and can quickly solidify when injected, providing mechanical strength sufficient for supporting the normal physiological activities of the bone. However, traditional bone cement lacks the ability to induce bone regeneration. Recently, various methods for enhancing the bone regeneration ability of bone cement have been developed, such as adding bone morphogenetic proteins, mesenchymal stem cells, and inorganic substances to bone cement. These methods not only ensure the original biological properties of the bone cement, but also improve the bone cement in terms of its mechanical strength and ability to induce bone regeneration. The aim of this review is to overview the process of bone regeneration, introduce improved bone cement formulations designed to promote bone regeneration, and discuss the clinical application of bone cement and its possibilities for future improvement.

In vivo mimicking injectable self-setting composite bio-cement: Scanning acoustic diagnosis and biological property evaluation for tissue engineering applications

Injectability and self-setting properties are important factors to increase the efficiency of bone regeneration and reconstruction, thereby reducing the invasiveness of hard tissue engineering procedures. In this study, 63S bioactive glass (BG), nano-hydroxyapatite (n-HAp), alumina, titanium dioxide, and methylene bis-acrylamide (MBAM)-mediated polymeric crosslinking composites were prepared for the formulation of an efficient self-setting bone cement. According to the cytocompatibility and physicochemical analyses, all the samples qualified the standard of the bio-composite materials. They revealed high thermal stability, injectability, and self-setting ability supported by ~ 10.73% (maximum) mass loss, ~ 92–93% injectability and 24 ± 5 min of initial setting time. Moreover, a cellular adhesion and proliferation study was additionally performed with osteoblasts like MG-63 cells, which facilitate pseudopod-like cellular extensions on the BG/n-HAp composite scaffold surface. The SAM study was employed to non-invasively assess the self-setting properties of the composite bio-cement using the post injected distribution and physical properties of the phantom. These results validate the significant potential characteristics of the BG/n-HAp self-setting bio-cement (16:4:2:1) for promising minimal-invasive bone tissue engineering applications.

A portable negative pressure unit reduces bone cement fumes in a simulated operating room

In this report, we demonstrate a versatile method for the removal of bone cement fumes from the vicinity of health care workers in a simulated operating room. The mixing of two component bone cement in the perimeter of an operating room releases volatile organic compounds (VOCs). The use of localized negative pressure within proximity of the mixing vessel is expected to reduce the concentration of VOCs dispersed near the airway of operating room personnel. A standard two component bone cement formulation was mixed in the perimeter of a simulated operating room. A median VOC concentration of 19 ppm was detected with a portable VOC detector. When a portable negative pressure unit was stationed near the mixing area at distances of 8 and 36 cm from the mixing vessel, the median VOC rise was reduced by approximately 97% and 83%, respectively, relative to the control. The use of a portable negative pressure unit provides a potential increase in the safety for all staff when working with materials that give off VOCs in the operating room.

Injectable bone cement containing carboxymethyl cellulose microparticles as a silver delivery system able to reduce implant-associated infection risk

In the challenging quest for a solution to reduce the risk of implant-associated infections in bone substitution surgery, the use of silver ions is promising regarding its broad spectrum on planktonic, sessile as well as multiresistant bacteria. In view of controlling its delivery in situ at the desired dose, we investigated its encapsulation in carboxymethyl cellulose (CMC) microparticles by spray-drying and included the latter in the formulation of a self-setting calcium phosphate bone cement. We implemented an original step-by-step methodology starting from the in vitro study of the antibacterial properties and cytotoxicity of two silver salts of different solubility in aqueous medium and then in the cement to determine the range of silver loading able to confer anti-biofilm and non-cytotoxic properties to the biomaterial. A dose-dependent efficiency of silver was demonstrated on the main species involved in bone-implant infection (S. aureus and S. epidermidis). Loading silver in microspheres instead of loading it directly inside the cement permitted to avoid undesired silver-cement interactions during setting and led to a faster release of silver, i.e. to a higher dose released within the first days combining anti-biofilm activity and preserved cytocompatibility. In addition, a combined interest of the introduction of about 10% (w/w) silver-loaded CMC microspheres in the cement formulation was demonstrated leading to a fully injectable and highly porous (77%) cement, showing a compressive strength analogous to cancellous bone. This injectable silver-loaded biomimetic composite cement formulation constitutes a versatile bone substitute material with tunable drug delivery properties, able to fight against bone implant associated infection. Statement of significanceThis study is based on two innovative scientific aspects regarding the literature: i) Choice of silver ions as antibacterial agent combined with their way of incorporation: Carboxymethylcellulose has never been tested into bone cement to control its drug loading and release properties. ii) Methodology to formulate an antibacterial and injectable bone cement: original and multidisciplinary step-by-step methodology to first define, through (micro)biological tests on two silver salts with different solubilities, the targeted range of silver dose to include in carboxymethylcellulose microspheres and, then optimization of silver-loaded microparticles processing to fulfill requirements (encapsulation efficiency and size). The obtained fully injectable composite controls the early delivery of active dose of silver (from 3 h and over 2 weeks) able to fight against bone implant-associated infections.

Defining the role of linoleic acid in acrylic bone cement

AbstractPolymethylmethacrylate is clinically used as a bone cement in various orthopedic and trauma surgeries. Post the surgery, such conventional acrylic bone cement has been reported to cause adjacent vertebral fractures; modifying it by adding linoleic acid in the formulation has shown potential in averting such fractures thanks to bone‐compliant mechanical properties, besides providing convenient handling properties. Although the resulting properties are attractive, the understanding of how linoleic acid imparts such advantageous properties remain unclear. Linoleic acid is typically sterilized in an autoclave before being used in the bone cement formulation; however, there are apprehensions whether the sterilization causes degradation. In this research, sterilized and unsterilized linoleic acid were evaluated alone and with different components of bone cement, such as activator, initiator, monomer, and inhibitor, and the ensuing structural changes in linoleic acid were monitored through 1H NMR and UV–Vis. The results reveal that linoleic acid degrade due to sterilization. In addition, evidence for reactions of sterilized/unsterilized linoleic acid with activator and initiator have been collected. We hypothesize that these reactions can reduce the availability of the components for the in situ polymerization of methyl methacrylate monomer and cause the improvement in handling properties and decrease in mechanical properties.

The impact of leuprolide acetate-loaded calcium phosphate silicate cement to bone regeneration under osteoporotic conditions

Osteoporosis is detrimental to the health of skeletal structure and significantly increases the risks of bone fracture. Moreover, bone regeneration is adversely impaired by increased osteoclastic activities as a result of osteoporosis. In this study, we developed a novel formulation of injectable bone cement based on calcium phosphate silicate cement (CPSC) and leuprolide acetate (LA). Several combinations of LA-CPSC bone cement were characterized and, it is found that LA could increase the setting time and compressive strength of CPSC in a concentration-dependent manner. Moreover, the in vitro results revealed that LA-CPSC was biocompatible and able to encourage the osteoblast proliferation via the mTOR signalling pathway. Furthermore, the LA-CPSC was implanted in the osteoporotic rats to evaluate its effectiveness to repair bone fractures under the osteoporotic conditions. The biomarker study and micro-CT analyses indicated that LA-CPSC could effectively reduce the osteoclast activities and promote the bone regeneration. In conclusion, our study demonstrated that LA-CPSC injectable bone cement should be a viable solution to repair bone fractures under the osteoporotic conditions.

Silanized graphene oxide as a reinforcing agent for acrylic bone cements: physicochemical, mechanical and biological characterization

Recently, different carbon-based nanomaterials have been used as reinforcing agents in acrylic bone cement formulations. Among them, graphene oxide (GO) has attracted the attention of scientific community since it could improve not only the mechanical properties but also the biocompatibility characteristics of these materials. However, using GO presents some drawbacks, such as its poor dispersion and lack of interaction with polymeric matrices, which should be prior resolved to achieve its optimal performance in acrylic bone cement. Thus, in this work, GO was treated with 3-methacryloxy propyl trimethoxy silane at various concentrations (1, 3 and 5 wt.%) to improve the interaction between the nanofiller and the poly (methyl methacrylate) matrix. Modified GO was incorporated at different percentages (0.1, 0.5 and 0.75 wt.%) into acrylic bone cement formulations and some properties were evaluated. The silanization process of the GO was confirmed by FTIR, TGA and EDX. The improvement in the mechanical performance was monitored on the compression properties whereas those related with biological properties were evaluated by osteoblast cell viability and hemocompatibility tests. Results suggest that using a 1 wt.% of the silane coupling agent, during surface treatment of GO, yields the best mechanical performance in this type of materials. It was also found that the presence of neat GO or silanized GO does not compromise the cytocompatibility and hemocompatibility of acrylic bone cement formulations.

Bone Cement Formulation with Reduced Heating of Bone Cement Resin

Bone cement material is one of the key materials in bone surgery and orthopedic medicine. In this study, commercial polymethyl-methacrylate bone cement was mixed with boric acid and zinc borate to reduce the reaction temperature of the bone cement. The observation of temperature changes during the polymerization using laser thermometer and thermal camera showed that the use of boron compounds decreased the temperature of the bone cement at least 10 °C which is very critical for the biomaterial uses as it affects the biocompatibility of the material. Besides temperature monitoring, microbiological tests showed that the materials have certain antibacterial effect. Water contact angle studies also supported the biocompatibility studies. In the last part, mechanical tests showed that there was not significant change in the tensile strength and tensile modulus values. Antibacterial tests exhibited that zinc borate addition shows antimicrobial activity against S.epidermidis as well as boric acid addition over %5 concentration. According to the cell culture studies, boric acid can be interpreted as non-toxic up to 10%, while 10% and 20% zinc borate has toxic effect. This is the first study to use boron compounds in bone cement and it is proved that boric acid at low concentrations can be used for bone cement applications but zinc borate would not be suitable to use in medical applications due to toxic effects.

Synthesis and characterization of magnetic and antibacterial nanoparticles as filler in acrylic cements for bone cancer and comorbidities therapy

In this work an innovative formulation of bone cement for the treatment of bone tumor and its associated complications has been designed by preparing a new class of Fe3O4–Ag nanostructures, using gallic acid as a reducing agent. The obtained nanoparticles have been introduced in polymethyl methacrylate (PMMA)-based composite cement evaluating the insertion of different amounts and the use of different mixing methods. The morphology, the composition and the antibacterial effect of Fe3O4–Ag nanostructures have been investigated together with the morphology, the composition, the mechanical properties of the nanoparticles-containing composite cements as well as their antibacterial effect.The obtained results revealed a good antimicrobial effect of Fe3O4–Ag nanostructures, a significant influence of their amount and of the used mixing method on the particles dispersion and agglomeration in the PMMA matrix and, as a result, on the mechanical properties. In particular, a better dispersion of nanoparticles was obtained by using the mechanical mixing, reducing the tendency to agglomerate. The increase of nanoparticles amount induced a slight decrease of the mechanical properties; however, the introduction of 10% w/w of Fe3O4–Ag allowed to improve the composites ability to reduce the bacteria adhesion.

Effects of the full-scale substitution of strontium for calcium on the microstructure of brushite: (CaxSr1–x)HPO4.nH2O system

AbstractBrushite (CaHPO4.2H2O) is an important calcium phosphate encountered in bone tissue engineering and bone cement formulation. There are many studies on the synthesis and characterization of brushite, but full-scale substitution and replacement of Ca by Sr in brushite as a key element in medical and environmental applications has not yet been explored systematically. Therefore, this study aims to evaluate the effects of substitution of Ca by Sr on the microstructural and thermal properties of brushite, including the chemical phases present, crystallization, structural water and phase stability. The chemical phases were determined by means of powder X-ray diffraction. The thermal properties were studied by thermogravimetric analysis. Crystallization and surface morphology were analysed using scanning electron microscopy. Various properties were dependent on the incorporated Sr ions. The replacement percentage of Sr may be divided into two major stages: the first from 0% to 50%; and the second from 50% up to 100%. The (CaxSr1–x)HPO4.nH2O shows that micro-scale crystals of platy brushite formed in the first stage of Sr replacement, from 0% up to 50%. As Sr might inhibit the formation of crystals, crystal nucleation rates were reduced as the Sr percentage increased. An amorphous product formed as a result of 50% Sr replacement. The second stage of Sr replacement with Sr contents >50% yielded a new crystal morphology corresponding mainly to SrHPO4.nH2O. The complete replacement of Ca by Sr transforms the brushite with platy microcrystals into SrHPO4 nanosheets.

Carboxylic acid-functionalized polycarbonates as bone cement additives for enhanced and sustained release of antibiotics

Despite the good clinical outcomes of total joint replacements, prosthetic joint infections still remain a significant cause of implant failure. Primary prophylaxis is key to stemming this burgeoning problem and its associated complications. In this study, a series of bone cement formulations with enhanced antibacterial performance have been developed through the addition of carboxylic acid-functionalized polycarbonate block copolymers to commercially available bone cement. Block copolymer design features were specifically tailored to modulate the acidity for adsorption of antibiotic and phase separation of the copolymers within the polymerizing/hardening of the cement during application. The best performing polymers demonstrated sustained antimicrobial release for more than 259 days and 147 days against S. aureus and P. aeruginosa, respectively, compared to 70 days of activity seen with commercially available gentamicin-containing cement control; whilst in vitro gentamicin release was increased by 8-fold. Total porosity was also increased 3-fold from 4.3% to 12.5%, whilst maintaining the mechanical integrity, working characteristics and osteoblastic biocompatibility of bone cement. Taken together, carboxylic acid-functionalized polycarbonates represent a promising class of bone cement additives that can be used to enhance the antibacterial performance of the bone cement whilst maintaining mechanical strength and cellular biocompatibility.

Development of Natural-Based Bone Cement for a Controlled Doxorubicin-Drug Release.

Osteosarcoma (OS) accounts for 60% of all global bone cancer diagnoses. Intravenous administration of Doxorubicin Hydrochloride (DOXO) is the current form of OS treatment, however, systemic delivery has been linked to the onset of DOXO induced cardiomyopathy. Biomaterials including calcium phosphate cements (CPCs) and nanoparticles (NPs) have been tested as localized drug delivery scaffolds for OS cells. However, the tumor microenvironment is critical in cancer progression, with mesenchymal stem cells (MSCs) thought to promote OS metastasis and drug resistance. The extent of MSC assisted survival of OS cells in response to DOXO delivered by CPCs is unknown. In this study, we aimed at investigating the effect of DOXO release from a new formulation of calcium phosphate-based bone cement on the viability of OS cells cocultured with hMSC in vitro. NPs made of PLGA were loaded with DOXO and incorporated in the formulated bone cement to achieve local drug release. The inclusion of PLGA-DOXO NPs into CPCs was also proven to increase the levels of cytotoxicity of U2OS cells in mono- and coculture after 24 and 72 h. Our results demonstrate that a more effective localized DOXO delivery can be achieved via the use of CPCs loaded with PLGA-DOXO NPs compared to CPCs loaded with DOXO, by an observed reduction in metabolic activity of U2OS cells in indirect coculture with hMSCs. The presence of hMSCs offer a degree of DOXO resistance in U2OS cells cultured on PLGA-DOXO NP bone cements. The consideration of the tumor microenvironment via the indirect inclusion of hMSCs in this study can act as a starting point for future direct coculture and in vivo investigations.

Optimization of the formulation of an original hydrogel-based bone cement using a mixture design

Highly swelling polymers, i.e. superabsorbent hydrogels, are hydrophilic, three dimensional networks that can easily absorb a significant amount water, fluid or drug. They are widely used in various applications such as foods, cosmetics, and medical devices.Bone cements are used in orthopaedics as a filling biomaterial or as a grout enhancing the embedding of a prosthesis into bone and fixation is achieved by mechanical interlock with metal or bone surfaces. Recently, hydrophilic bone cements have attracted the attention for bone tissue-engineering applications.Here a bone cement containing an acrylic hydrogel (HEMA) as a liquid phase and a blend of corn starch, cellulose acetate and bioceramic filler as a solid phase is investigated by means of a mixture design which is a special topic within statistical Design of Experiments (DoE). Output variables of interest, complex shear modulus, compressive modulus and swelling rate related to rheological, mechanical and swelling properties respectively, are measured for each cement formulation.Applying the mixture design strategy enables to assess the impact of the three powder components on each variable of interest and to determine the optimal formulation in order to achieve the required properties of this HEMA-based bone cement, especially the rheology adapted to the desired clinical application, but also appropriate mechanical and swelling properties.

Brushite (Ca,M)HPO4, 2H2O doping with bioactive ions (M = Mg2+, Sr2+, Zn2+, Cu2+, and Ag+): a new path to functional biomaterials?

Dicalcium phosphate dihydrate, DCPD (CaHPO4·2H2O), brushite, is an important calcium phosphate compound encountered in mineralized tissues and used in medicine, especially in bone cement formulations. However, the use of DCPD as direct implantable biomaterial has not received dedicated attention. In addition, the possibility to dope DCPD with biologically active ions to modulate its performances was not systematically explored. We have investigated in depth the doping of DCPD with Mg2+, Sr2+, Zn2+, Cu2+, and Ag+ ions. Clear modifications in terms of chemical composition, particle size, pore distribution, crystal morphology, and affinity for water were pointed out. Then, the samples were cultured with human adipose-derived stem cells to explore cytotoxicity and proliferation. Various behaviors were noticed dependent on the incorporated metal ions. Such DCPD compounds associated with bioactive metal ions, and particularly Ag+ and Zn2+, appear promising as a new family of reactive materials for use, as such or in combination, in bone-related applications.

Formulation of α-Tricalcium Phosphate Bone Cement Based on an Alginate–Chitosan Gel System

A new formulation of α-tricalcium phosphate (α-TCP) bone cement with controllable hydration was developed by employing an internal polymeric gel network. Conjunction of two Ca-chelating agents, sod...