Injectable Calcium Phosphate Cement Research Articles

CmRNA/lipoplex encapsulation in PLGA microspheres enables transfection via calcium phosphate cement (CPC)/PLGA composites

In this study lipoplexes containing chemically modified messenger RNA (cmRNA) were incorporated into poly (lactic-co-glycolic acid) (PLGA) microspheres via water-in-oil-in-water (W/O/W) double emulsion solvent evaporation technique. The nanoparticle encapsulation by microparticle formation was optimized to achieve lipoplex release and maximum transfection efficiency in surrounding cells. It was possible to adjust characteristic features in surface topology and size of the PLGA-microspheres by varying the extent of lipoplex loading into the polymer matrix. The partial release of lipids and mRNA out of the microparticle system, their accumulation in cells and the production of encoded protein were visualized via fluorescence microscopy. These bioactive microspheres, containing cmRNA bearing lipoplexes, were developed for the incorporation of a therapeutic component into injectable calcium phosphate cements (CPC). Due to the incorporation of PLGA/lipoplex microspheres as a degradable entity, the porosity of the cement phase could additionally be adjusted. This approach of complex nanoparticle incorporation into polymer/cement composites represents a promising example for combining transcript therapy with biomechanical engineering.

Recent Developments on Injectable Calcium Phosphate Bone Cement

New emerging micro-invasive bone grafting techniques have recently risen the interest towards injectable calcium phosphate cement (CPC) as bone filling material that is able to set itself within the body temperature. There are various formulations of injectable CPC that have been developed in recent years. The development of injectable CPC mainly focuses on getting optimum setting times, mechanical properties, injection capabilities and in vivo properties so that the cement is clinically applicable for biomedical applications. The existing studies on injectable CPCs have investigated the effects of some factors, such as liquid to powder (P/L) ratio, types solid and liquid phase used, concentration of the liquid phase, density and porosity of the cement, particle size of the cement powder and its crystallinity, needle size, and use of setting retardants, setting accelerators and cohesion promoters on the handling, mechanical and biological properties of the cement. The aim of this paper is to review the recent developments of injectable CPC for bone filling materials. Some prominent patents related to the developments of injectable CPC are also reviewed. Keywords: Biological properties, bone cement, calcium phosphate, injectability, mechanical properties, setting agent, setting time.

Evaluation of resistance to fragmentation of injectable calcium-phosphate cement paste using X-ray microcomputed tomography

Evaluation of resistance to fragmentation of injectable calcium-phosphate cement paste using X-ray microcomputed tomography

Incorporation of fast dissolving glucose porogens into an injectable calcium phosphate cement for bone tissue engineering.

Calcium phosphate cements have shown great promise for the regeneration of bone. However, macropores (>100μm) are required for promoting bone ingrowth. Several studies have investigated methods to generate macroporosity within calcium phosphate cements but many of these methods either affect the cement setting or take weeks or months to generate the maximum porosity. This work offers a new method for generating macroporosity within calcium phosphate cements by utilizing glucose microparticles. The microparticles dissolve in less then 72h, thereby generating scaffolds with maximum porosity in short period of time. The results will offer a new method for generating macroporosity within calcium phosphate cements.

Long-term biological performance of injectable and degradable calcium phosphate cement

Enhancing degradation of poorly degrading injectable calcium phosphate (CaP) cements (CPCs) can be achieved by adding poly(lactic-co-glycolic acid) (PLGA) microparticles, generating porosity after polymer degradation. CPC-PLGA has proven to be biodegradable, although its long-term biological performance is still unknown. Optimization of injectability could be achieved via addition of carboxymethyl cellulose (CMC). Here, we evaluated the long-term in vivo performance of CPC-PLGA with or without the lubricant CMC in comparison to the devitalized bovine bone mineral (DBBM) predicate device Bio-Oss®. Rabbit femoral bone defects were injected with a CPC-formulation or filled with Bio-Oss® granules. Samples were retrieved at 6 and 26 weeks. Material degradation for Bio-Oss® was marginal, starting with 57% material remnants at implantation, 49% at 6 weeks, and 35% at 26 weeks, respectively. In contrast, CPC-PLGA and CPC-PLGA-CMC showed significant material degradation, starting with 100% material remnants at implantation, 56 and 78% at 6 weeks, and 8 and 21% at 26 weeks. Bone formation showed to be rapid for Bio-Oss®, with 24% at 6 weeks, and a similar value (27%) at 26 weeks. Both CPC-PLGA and CPC-PLGA-CMC showed a continuous temporal increase in bone formation, with 13 and 6% at 6 weeks, and 44 and 32% at 26 weeks. This study showed that CPC-PLGA induces favorable bone responses with >90% degradation and >40% new bone formation after an implantation period of 26 weeks.

Traitements des enchondromes à la main avec un ciment phosphocalcique injectable : à propos de 8 cas

The gold standard treatment for enchondroma in the hand is curettage and filling of the defect. The goal of this study was to evaluate the results when injectable calcium phosphate cement is used to fill the bone defect. Eight patients having a mean age of 44 years were operated through a minimally invasive skin incision. After a small bone window was made, curettage of the lesion was performed and verified by intraosseous endoscopy. The defect was filled with injectable calcium phosphate cement (AREXyBONE, AREXy, Palaiseau, France). The mean pain score (out of 10) decreased from 4.1 preoperatively to 1.6 postoperatively. The mean QuickDASH (out of 100) improved from 37.66 to 24.14. At the last follow-up (mean of 16 months), the range of motion in the operated hand had reached 89.3% of the contralateral hand. Based on radiographs, a mean of 69.3% calcium phosphate cement remained in the bone. There were two cases of extraosseous cement leakage, one of which required revision and resulted in a poor outcome. Overall, these results show that curettage of a hand enchondroma followed by filling of the defect with injectable calcium phosphate cement is a simple, reliable technique with no donor site morbidity, as long as cement does not leak out.

Critical review: Injectability of calcium phosphate pastes and cements.

Occurrence of phase separation of calcium phosphate pastes and cements during injection limits their full exploitation as a bone substitute in minimally invasive surgical applications. Due to lack of theoretical understanding of the phase separation mechanism(s), optimisation of an injectable CPC that satisfies clinical requirements has proven difficult. However, phase separation of pastes during delivery has been the focus across several research fields. Therefore in addition to a review of methods to reduce phase separation of CPC and the associated constraints, a review of phase separation mechanisms observed during extrusion of other pastes and the theoretical models used to describe these mechanisms is presented. It is anticipated this review will benefit future attempts to develop injectable calcium phosphate based systems.

Hydrogel fibers encapsulating human stem cells in an injectable calcium phosphate scaffold for bone tissue engineering

Human induced pluripotent stem cells (hiPSCs), human embryonic stem cells (hESCs) and human umbilical cord mesenchymal stem cells (hUCMSCs) are exciting cell sources for use in regenerative medicine. There have been no reports on long hydrogel fibers encapsulating stem cells inside an injectable calcium phosphate cement (CPC) scaffold for bone tissue engineering. The objectives of this study were: (1) to develop a novel injectable CPC construct containing hydrogel fibers encapsulating cells for bone engineering, and (2) to investigate and compare cell viability, proliferation and osteogenic differentiation of hiPSC-MSCs, hESC-MSCs and hUCMSCs in injectable CPC. The pastes encapsulating the stem cells were fully injectable under a small injection force, and the injection did not harm the cells, compared with non-injected cells (p > 0.1). The mechanical properties of the stem cell–CPC construct were much better than those of previous injectable polymers and hydrogels for cell delivery. The hiPSC-MSCs, hESC-MSCs and hUCMSCs in hydrogel fibers in CPC had excellent proliferation and osteogenic differentiation. All three cell types yielded high alkaline phosphatase, runt-related transcription factor, collagen I and osteocalcin expression (mean ± SD; n = 6). Cell-synthesized minerals increased substantially with time (p < 0.05), with no significant difference among the three types of cells (p > 0.1). Mineralization by hiPSC-MSCs, hESC-MSCs and hUCMSCs in CPC at 14 d was 13-fold that at 1 d. In conclusion, all three types of cells (hiPSC-MSCs, hESC-MSCs and hUCMSCs) in a CPC scaffold showed high potential for bone tissue engineering, and the novel injectable CPC construct with cell-encapsulating hydrogel fibers is promising for enhancing bone regeneration in dental, craniofacial and orthopedic applications.

Assessment of bone healing ability of calcium phosphate cements loaded with platelet lysate in rat calvarial defects.

Injectable calcium phosphate cements have been used as a valid alternative to autologous bone grafts for bone augmentation with the additional advantage of enabling minimally invasive implantation procedures and for perfectly fitting the tissue defect. Nevertheless, they have low biodegradability and lack adequate biochemical signaling to promote bone healing and remodeling. In previous invitro studies, we observed that the incorporation of platelet lysate directly into the cement paste or loaded in hyaluronic acid microspheres allowed to modulate the cement degradation and the invitro expression of osteogenic markers in seeded human adipose derived stem cells. The present study aimed at investigating the possible effect of this system in new bone formation when implanted in calvarial bilateral defects in rats. Different formulations were assessed, namely plain calcium phosphate cements, calcium phosphate cements loaded with human platelet lysate, hybrid injectable formulations composed of the calcium phosphate cement incorporating hyaluronin acid non-loaded microparticles (20% hyaluronin acid) or with particles loaded with platelet lysate. The degradability and new bone regrowth were evaluated in terms of mineral volume in the defect, measured by micro-computed tomography and histomorphometric analysis upon 4, 8 and 12 weeks of implantation. We observed that the incorporation of hyaluronin acid microspheres induced an overly rapid cement degradation, impairing the osteoconductive properties of the cement composites. Moreover, the incorporation of platelet lysate induced higher bone healing than the materials without platelet lysate, up to four weeks after surgery. Nevertheless, this effect was not found to be significant when compared to the one observed in the sham-treated group.

Enchondroma in the distal phalanx of the finger: An observational study of 34 cases in a single institution.

The goal of our study was to report the clinical presentation, treatment, and complications of enchondroma in the distal phalanx of the finger. This was a retrospective study of 34 patients (19 women and 15 men) who underwent surgery between May 2004 and September 2012 for enchondroma in the distal phalanx of the finger. The average age of the patients was 39.38 ± 10.97 years old (range 14–59). The presenting symptoms and imaging features were recorded. The surgical procedure was performed under regional or general anesthesia. The surgical technique involved removal of tumors by opening a cortical window and curetting the cavity. The defects were filled with an injectable calcium phosphate cement. All patients received follow-up in our outpatient clinic every 6 months. Expansion of bone or thinning of the cortex present in the radiological imaging, including anteroposterior and lateral plain radiographs of the fingers, was used to assess for tumor recurrence. The observational end-point was reoperation.All tumors were confirmed as enchondromas by the pathological results. None of the patients had a tumor recurrence. Three patients (9% of cases) developed an infection. After antibiotic treatment, 2 patients were cured, and 1 patient required an amputation. Enchondroma in the distal phalanx of the finger presents with a variety of clinical symptoms. Injectable calcium phosphate cement is adequate for bone grafting. Postoperative infection is more common than tumor recurrence. If patients have an infection or bilateral bone cortex defects, bone grafting is challenging.Level of Evidence: Therapeutic study, Level IV

Second generation locked plating for complex proximal humerus fractures in very elderly patients

ObjectivesHumeral head sacrificing procedures are more favored in elderly patients with complex proximal humerus fractures because of high incidence of failures and complications with osteosynthesis. The purpose of this study is to assess the outcome of second generation locked plating techniques in 3 and 4 part fractures in active elderly patients >70years with an emphasis on function and complications. Materials and methods29 patients with displaced 3 and 4 part proximal humerus fractures were treated using the principles of second-generation proximal humerus locked plating. Fixed angle locked plating (PHILOS) using the anterolateral deltoid spilt approach augmented with traction cuff sutures was performed. Minimum of 7 locking head screws including 2 calcar screws were used. In cases with a comminuted medial calcar, an endosteal fibular strut was used. Subchondral metaphyseal bone voids were filled with injectable calcium phosphate cement. Radiological outcome (union, head – shaft angle, tuberosity reduction), functional outcome assessment (Constant and ASES scores) and complications (loss of reduction, nonunion and osteonecrosis) were assessed. ResultsThe fracture united in 24 of the 26 patients available for follow up at a mean of 27 months (12–40 months). 3 patients developed complications that required arthroplasty (fixation failure in 2 patients and osteonecrosis in 1 patient). Follow up age adjusted Constant (63.1±11.9) and ASES scores (62.58±7.5) showed the extent of functional improvement post surgery. Patients with fractures having a non-comminuted medial calcar and valgus displacement of the humeral head had better functional scores and fewer complications. ConclusionOsteosynthesis with second generation locked plating techniques provide satisfactory outcome in very elderly patients with complex proximal humerus fractures with minimal complications.

Injectable calcium phosphate with hydrogel fibers encapsulating induced pluripotent, dental pulp and bone marrow stem cells for bone repair

Human induced pluripotent stem cell-derived mesenchymal stem cells (hiPSC-MSCs), dental pulp stem cells (hDPSCs) and bone marrow MSCs (hBMSCs) are exciting cell sources in regenerative medicine. However, there has been no report comparing hDPSCs, hBMSCs and hiPSC-MSCs for bone engineering in an injectable calcium phosphate cement (CPC) scaffold. The objectives of this study were to: (1) develop a novel injectable CPC containing hydrogel fibers encapsulating stem cells for bone engineering, and (2) compare cell viability, proliferation and osteogenic differentiation of hDPSCs, hiPSC-MSCs from bone marrow (BM-hiPSC-MSCs) and from foreskin (FS-hiPSC-MSCs), and hBMSCs in CPC for the first time. The results showed that the injection did not harm cell viability. The porosity of injectable CPC was 62%. All four types of cells proliferated and differentiated down the osteogenic lineage inside hydrogel fibers in CPC. hDPSCs, BM-hiPSC-MSCs, and hBMSCs exhibited high alkaline phosphatase, runt-related transcription factor, collagen I, and osteocalcin gene expressions. Cell-synthesized minerals increased with time (p<0.05), with no significant difference among hDPSCs, BM-hiPSC-MSCs and hBMSCs (p>0.1). Mineralization by hDPSCs, BM-hiPSC-MSCs, and hBMSCs inside CPC at 14d was 14-fold that at 1d. FS-hiPSC-MSCs were inferior in osteogenic differentiation compared to the other cells. In conclusion, hDPSCs, BM-hiPSC-MSCs and hBMSCs are similarly and highly promising for bone tissue engineering; however, FS-hiPSC-MSCs were relatively inferior in osteogenesis. The novel injectable CPC with cell-encapsulating hydrogel fibers may enhance bone regeneration in dental, craniofacial and orthopedic applications.

Properties and Cytocompatibility of Anti-Washout Calcium Phosphate Cement by Introducing Locust Bean Gum

The washout resistance of injectable calcium phosphate cement (CPC) is highly requisite for more widely clinical applications. In this work, locust bean gum (LBG) was used as the anti-washout agent to improve the washout resistance of CPC. The results indicated that the washout resistance was greatly improved, and meanwhile the injectability, setting time and compressive strength slightly decreased when the content of LBG was no more than 1.0%. Additionally, the CPC with 1.0% LBG exhibited good cell compatibility of the mouse bone mesenchymal stem cells (mBMSCs). Therefore, the 1.0% LBG content was proposed to serve as a useful additive in CPC as a result of its ability to promote washout resistance, which may play an important role in clinical applications.

An ultrasonic through-transmission technique for monitoring the setting of injectable calcium phosphate cement

An ultrasound through-transmission method to monitor the setting process of injectable calcium phosphate bone cements in body fluids is presented. This method can be used to determine the acoustic properties of the bone cement as it sets, which are linked to its material properties and provide some information about changes occurring within the cement. The development of the methodology of ultrasonic testing and execution of velocity measurements of the longitudinal and transverse waves using the through-transmission method made it possible to determine the material constants of samples during the setting and hardening process of an injectable cement paste in physiological fluids (i.e. the Young's modulus (E), the Poisson ratio (ν) and the shear modulus (G)), and to determine the degree of anisotropy of wave velocity in the samples. A strong advantage of the proposed method is that it is non-destructive, and the same sample can be used to monitor the whole process of the cement setting. The testing was performed on premixed and injectable calcium phosphate (CPC)/chitosan blend, where glycerol was used as a liquid phase. Comparisons between ultrasonic velocity and empirical tests such as compressive strength, porosity measurement, FTIR, SEM and XRD analysis at different days of immersion in Ringer's solutions showed that the ultrasonic velocity can be very useful to provide in situ information about changes occurring within the cement.

Controlled Release of Chemotherapeutic Platinum-Bisphosphonate Complexes from Injectable Calcium Phosphate Cements.

Herein, we present a method to release chemotherapeutic platinum-bisphosphonate (Pt-BP) complexes from apatitic calcium phosphate cements (CPCs). Pt-BP-loaded hydroxyapatite nanoparticles (HA NPs) were added at different ratios to the powder phase of the cements, which contained poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres as porogens to accelerate their degradation. In vitro release kinetics of Pt-BP complexes revealed that the release rate of Pt species can be tuned by varying the amount of drug-loaded HA NPs as well as modifying the chemical structure of the Pt-BP complex to tailor its affinity with HA NPs. In addition, the incorporation of PLGA microspheres into the CPCs increased the degradation rate of the materials without affecting the release rate of Pt species. Finally, the antiproliferative activity of the free Pt-BP complexes and Pt-BP-loaded CPCs was evaluated using both human osteosarcoma cancer cells (MG-63) and human bone marrow-derived mesenchymal stromal cells (h-BMMSCs). This study demonstrated that both free Pt-BP complexes and the releasates from the CPCs were antiproliferative in a dose-dependent manner. Moreover, their antiproliferative activity was higher on MG-63 cells compared to h-BMMSC primary cells. In summary, it was shown that injectable CPCs can be rendered chemotherapeutically active by incorporation of HA NPs loaded with HA-binding Pt-BP complexes.

Endoscopic Versus Open Surgery for Calcaneal Bone Cysts: A Preliminary Report

The purpose of the present study was to evaluate the advantages and disadvantages of an endoscopic procedure for patients with symptomatic calcaneal bone cyst compared with an open procedure. The cases of 16 consecutive patients with a calcaneal bone cyst were reviewed. Of the 16 patients, 8 had undergone the open procedure (O group) from October 2003 to August 2011, and 8 had undergone the endoscopic procedure (E group) from September 2011 to April 2013. The endoscopic procedure used a 2-portal technique in which skin incisions were made to avoid the peroneal tendon according to the preoperative ultrasonography. All surgeries (open or endoscopic) consisted of curettage of the inner wall of the bone cyst, followed by injection of calcium phosphate cement. The following factors were evaluated: radiographic assessment, operative time, postoperative adverse effects, and interval to the return to sports. No significant difference between the 2 groups was observed in the operative time (53.5 ± 6.5 minutes in the O group and 56.1 ± 13.8 minutes in the E group). The E group experienced no adverse effects; however, the O group had 1 temporary irritation in the sural nerve area and 1 calcium phosphate cement leakage along the peroneal tendon sheath. The interval to a return to sports was significantly shorter in the E group (14.5 ± 0.9 weeks in the O group and 6.5 ± 1.1 weeks in the E group; p < .01). In conclusion, endoscopic surgery is a useful approach for the treatment of calcaneal bone cysts, allowing early rehabilitation and an early return to sports without any adverse effects.

Open-Wedge High Tibial Osteotomy: RCT 2 Years RSA Follow-Up.

We investigated the influence of three different bone grafting materials on stability and clinical outcome of the healing open-wedge high tibial osteotomy (OW-HTO) with immediate partial weight bearing. A total of 45 (3 × 15) patients were randomized to injectable calcium phosphate cement (Calcibon; Biomet-Merck Biomaterials GmbH, Darmstadt, Germany), local bone autograft, or iliac crest autograft. Stability of the bony healing was evaluated with radiostereometric analysis (RSA) up to 24 months postoperatively. Clinical outcome was evaluated with the knee injury and osteoarthritis outcome score (KOOS). RSA revealed translations and rotations close to zero regardless of bone grafting material, with no statistically significant differences between the groups. Clinically, the Calcibon group had lower quality of life KOOS subscore at 2 years follow-up. We conclude that with a stable implant and 6 weeks of partial weight bearing, local autografting is sufficient to achieve solid bone consolidation following OW-HTO.

Making the most of additive layer manufacture - development of tailored titanium implants with embedded therapeutics

Event Abstract Back to Event Making the most of additive layer manufacture - development of tailored titanium implants with embedded therapeutics Sophie Cox1, Hany Hassanin2*, Parastoo Jamshidi2*, Moataz Attallah2*, Duncan Shepherd3*, Owen Addison4* and Liam Grover1* 1 University of Birmingham, Chemical Engineering, United Kingdom 2 University of Birmingham, Materials and Metallurgy, United Kingdom 3 University of Birmingham, Mechanical Engineering, United Kingdom 4 University of Birmingham, Dentistry, United Kingdom Introduction: Musculoskeletal disorders cost society an estimated $254 billion annually[1]. Common metallic alloys used for bone prostheses, including titanium, exhibit modulus values significantly higher than native bone tissue. This mismatch results in a phenomena called stress shielding, which ultimately may impact implant functionality and patient quality of life. Furthermore, despite low incidence rates, infection of primary and revision prostheses represents one of the most serious and devastating complications[2]. Since invention in the 1980s, additive layer manufacture (ALM) techniques have been employed in a number of industries. The utilisation of such methods has provided researchers with improved geometrical design flexibility since the part is manufactured from a model constructed using computer aided design (CAD) software, which circumvents a number of limitations associated with traditional techniques, such as casting. Primarily, ALM techniques have been employed in medicine to manufacture tailored implants created from patient geometries obtained from CT or MRI data. We propose that these manufacturing modalities may be further exploited to address stress shielding and infection issues related to bone prostheses. In this case study we demonstrate the design and manufacture of novel implant models using selective laser melting (SLM), that incorporate a mechanically optimised reservoir containing a secondary biomaterial phase loaded with a therapeutic reagent. Materials and Methods: A dental screw model was altered using CAD (Solidworks) to incorporate a central reservoir connected to the extremities via four pore channels on the bottom face of the part (Figure 1). Implants were manufactured from a Ti-6Al-4V alloy using a Concept M2 Cusing System. Structures were then loaded with injectable calcium phosphate cements containing gentamicin sulphate as a model antibiotic. Results: Micro-CT revealed successful infiltration of the reservoir with optimised cement formulations. The majority, >80%, of cement porosity was found to be open and this is suggested to have contributed to release of gentamicin sulphate, which was monitored by UV absorbance. Within 72 hours the antibiotic payload had been released from the implant and was shown, using an agar diffusion assay, to inhibit the growth of staphylococcus aureus and epidermis bacteria. Conclusions: Restoring the structure and function of musculoskeletal disorders, particularly in areas of significant load bearing, continues to challenge researchers and clinicians. Promisingly, this case study demonstrates that by fully utilising the geometrical design flexibility of ALM further mechanical and therapeutic functionality may be incorporated into bone prostheses. The results of this study show that this innovative approach has the potential to address stress shielding and infection issues associated with implants, which currently devastatingly impact patient quality of life. EPSRC for financially supporting this research (EP/L020815/1)

Inflammation-mediated drug release using a gas-generating system for treating osteomyelitis

Event Abstract Back to Event Inflammation-mediated drug release using a gas-generating system for treating osteomyelitis Wei-Lin Wan1*, Ming-Fan Chung1*, Yi-Jun Lin1* and Hsing-Wen Sung1, 2* 1 National Tsing Hua University, Department of Chemical Engineering, Taiwan 2 National Tsing Hua University, Institute of Biomedical Engineering, Taiwan In the conventional treatment of osteomyelitis, the penetration of antibiotics into the infected bone is commonly poor. To ensure that the local antibiotic concentration is adequate, this work develops an injectable calcium phosphate (CP) cement in which is embedded pH-responsive hollow microspheres (HMs) that can control the release of a drug according to the local pH. The HMs are fabricated using a microfluidic device, with a shell of poly(D,L-lactic-co-glycolic acid) (PLGA) and an aqueous core that contains vancomycin (Van) and NaHCO3. At neutral pH, the CP/HM cement elutes a negligible concentration of the drug. In an acidic environment, the NaHCO3 that is encapsulated in the HMs reacts with the acid rapidly to generate CO2 bubbles, disrupting the PLGA shells and thereby releasing Van locally in excess of a therapeutic threshold. The feasibility of using this CP/HM cement to treat osteomyelitis is studied using a rabbit model. Analytical results reveal that the CP/HM cement provides highly effective local antibacterial activity. Histological examination further verifies the efficacy of the treatment by the CP/HM cement. The above findings suggest that the CP/HM cement is a highly efficient system for the local delivery of antibiotics in the treatment of osteomyelitis. Keywords: in vivo, Drug delivery, stimuli-response, Biodegradable material Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Biomaterials for therapeutic delivery Citation: Wan W, Chung M, Lin Y and Sung H (2016). Inflammation-mediated drug release using a gas-generating system for treating osteomyelitis. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01352 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. * Correspondence: Dr. Wei-Lin Wan, National Tsing Hua University, Department of Chemical Engineering, Hsinchu, Taiwan, Email1 Dr. Ming-Fan Chung, National Tsing Hua University, Department of Chemical Engineering, Hsinchu, Taiwan, gary940638@gmail.com Dr. Yi-Jun Lin, National Tsing Hua University, Department of Chemical Engineering, Hsinchu, Taiwan, Email2 Dr. Hsing-Wen Sung, National Tsing Hua University, Department of Chemical Engineering, Hsinchu, Taiwan, hwsung@mx.nthu.edu.tw Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Wei-Lin Wan Ming-Fan Chung Yi-Jun Lin Hsing-Wen Sung Google Wei-Lin Wan Ming-Fan Chung Yi-Jun Lin Hsing-Wen Sung Google Scholar Wei-Lin Wan Ming-Fan Chung Yi-Jun Lin Hsing-Wen Sung PubMed Wei-Lin Wan Ming-Fan Chung Yi-Jun Lin Hsing-Wen Sung Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

A simple and effective approach to prepare injectable macroporous calcium phosphate cement for bone repair: Syringe-foaming using a viscous hydrophilic polymeric solution

In this study, we propose a simple and effective strategy to prepare injectable macroporous calcium phosphate cements (CPCs) by syringe-foaming via hydrophilic viscous polymeric solution, such as using silanized-hydroxypropyl methylcellulose (Si-HPMC) as a foaming agent. The Si-HPMC foamed CPCs demonstrate excellent handling properties such as injectability and cohesion. After hardening the foamed CPCs possess hierarchical macropores and their mechanical properties (Young’s modulus and compressive strength) are comparable to those of cancellous bone. Moreover, a preliminary in vivo study in the distal femoral sites of rabbits was conducted to evaluate the biofunctionality of this injectable macroporous CPC. The evidence of newly formed bone in the central zone of implantation site indicates the feasibility and effectiveness of this foaming strategy that will have to be optimized by further extensive animal experiments. Statement of significanceA major challenge in the design of biomaterial-based injectable bone substitutes is the development of cohesive, macroporous and self-setting calcium phosphate cement (CPC) that enables rapid cell invasion with adequate initial mechanical properties without the use of complex processing and additives. Thus, we propose a simple and effective strategy to prepare injectable macroporous CPCs through syringe-foaming using a hydrophilic viscous polymeric solution (silanized-hydroxypropyl methylcellulose, Si-HPMC) as a foaming agent, that simultaneously meets all the aforementioned aims. Evidence from our in vivo studies shows the existence of newly formed bone within the implantation site, indicating the feasibility and effectiveness of this foaming strategy, which could be used in various CPC systems using other hydrophilic viscous polymeric solutions.