Cartilage injuries often represent irreversible tissue damage because cartilage has only a low ability to regenerate. Thus, cartilage loss results in permanent damage, which can become the starting point for osteoarthritis. In the past, bioactive glass scaffolds have been developed for bone replacement and some of these variants have also been colonized with chondrocytes. However, the hydroxylapaptite phase that is usually formed in bioglass scaffolds is not very suitable for cartilage formation (chondrogenesis). This interdisciplinary project was undertaken to develop a novel slowly degrading bioactive glass scaffold tailored for cartilage repair by resembling the native extracellular cartilage matrix (ECM) in structure and surface properties. When colonized with articular chondrocytes, the composition and topology of the scaffolds should support cell adherence, proliferation and ECM synthesis as a prerequisite for chondrogenesis in the scaffold. To study cell growth in the scaffold, the scaffolds were colonized with human mesenchymal stromal cells (hMSCs) and primary porcine articular chondrocytes (pACs) (27,777.8 cells per mm. 3. ) for 7 – 35 d in a rotatory device. Cell survival in the scaffold was determined by vitality assay. Scanning electron microscopy (SEM) visualized cell ultramorphology and direct interaction of hMSCs and pACs with the bioglass surface. Cell proliferation was detected by CyQuant assay. Subsequently, the production of sulphated glycosaminoglycans (sGAGs) typical for chondrogenic differentiation was depicted by Alcian blue staining and quantified by dimethylmethylene blue assay assay. Quantitative real-time polymerase chain reaction (QPCR) revealed gene expression of cartilage-specific aggrecan, Sox9, collagen type II and dedifferentiation-associated collagen type I. To demonstrate the ECM-protein synthesis of the cells, the production of collagen type II and type I was determined by immunolabelling. The bioactive glass scaffold remained stable over the whole observation time and allowed the survival of hMSCs and pACs for 35 days in culture. The SEM analyses revealed an intimate cell-biomaterial interaction for both cell types showing cell spreading, formation of numerous filopodia and ECM deposition. Both cell types revealed initial proliferation, decreasing after 14 days and becoming elevated again after 21 days. hMSCs formed cell clusters, whereas pACs showed an even distribution. Both cell types filled more and more the pores of the scaffold. The relative gene expression of cartilage-specific markers could be proven for hMSCs and pACs. Cell associated sGAGs deposition could be demonstrated by Alcian blue staining and sGAGs were elevated in the beginning and end of the culturing period. While the production of collagen type II could be observed with both cell types, the synthesis of aggrecan could not be detected in scaffolds seeded with hMSCs. hMSCs and pACs adhered, spread and survived on the novel bioactive glass scaffolds and exhibited a chondrocytic phenotype

Introduction and Objective. Bone is a tissue which continually regenerates and also having the ability to heal after injuries however, healing of large defects requires intensive surgical treatment. Bioactive glasses are unique materials that can be utilized in both bone and skin regeneration and repair. They are degradable in physiological fluids and have osteoconductive, osteoinductive and osteostimulative properties. Osteoinductive growth factors such as Bone Morphogenetic Proteins (BMP), Vascular Endothelial Growth Factor (VEGF), Epidermal Growth Factor (EGF), Transforming Growth Factor (TGF) are well known to stimulate new bone formation and regeneration. Unfortunately, the synthesis of these factors is not cost- effective and, the broad application of growth factors is limited by their poor stability in the scaffolds. Instead, it is wise to incorporate osteoinductive nanomaterials such as graphene nanoplatelets into the structures of synthetic scaffolds. In this study, borate-based 13-93B3 bioactive glass scaffolds were prepared by polymer foam replication method and they were coated with graphene-containing poly (ε-caprolactone) layer to support the bone repair and regeneration. Materials and Methods. Effects of graphene concentration (1, 3, 5, 10 wt%) on the healing of rat segmental femur defects were investigated in vivo using male Sprague–Dawley rats. Fabricated porous bioactive glass scaffolds were coated by graphene- containing polycaprolactone solution using dip coating method. The prepared 0, 1, 3, 5 and 10 wt% graphene nanoparticle-containing PCL-coated composite scaffolds were designated as BG, 1G-P-BG, 3G-P-BG, 5G-P-BG and 10G-P-BG, for each group (n: 4) respectively. Histopathological and immunohistochemical (bone morphogenetic protein, BMP-2; smooth muscle actin, SMA and alkaline phosphatase, ALP) examinations were made after 4 and 8 weeks of implantation. Results. Results showed that after 8-weeks of implantation both cartilage and bone formation were observed in all animal groups. After 4 and 8 weeks of implantation the both osteoblast and osteoclast numbers were significantly higher in the group 4 compared to the control group. Bone formation was significant starting from 1 wt% graphene-coated bioactive glass implanted group and highest amount of bone formation was obtained in group containing 10 wt% graphene (p<0.001). Newly formed vessels expressed this marker and increased vascularization was observed in 8- weeks period compared to the 4-weeks period. In addition, an increase in new vessel formation were observed in graphene-coated scaffold implanted groups compared to the control group. While cartilage tissue was observed in control group, bone formation percentages were significant in graphene-coated scaffold implanted groups. Highest amount of bone formation occurred in group 4 (10 % wt G-C). Conclusions. Additionally, the presence of graphene nanoplatelets enhanced the BMP-2, SMA and ALP levels compared to the bare bioactive glass scaffolds. It was concluded that pristine graphene-coated bioactive glass scaffolds improve osteointegration and bone formation in rat femur defect when compared to bare bioglass scaffolds

Aim. Biomaterial-associated infections (BAI) present a formidable clinical challenge. Bioactive glasses (BG) have proven highly successful in diverse clinical applications, especially in dentistry and orthopaedics. In this study, we aimed to determine the effect of three commonly used BG composition and particle sizes on cell and bacterial attachment and growth. Our focus is on understanding the changes in pH and osmotic pressure in the surrounding environment during glass degradation. Method. First, three different melt-derived glasses were characterized by analyzing particle size and glass network structure using Raman and NMR. The different glasses were then tested in vitro by seeding 4x 10. 4. cells/well (SaOS Cell line) in a 48 well plate. After a pre-incubation period of 72 hours, the different BGs and particle sizes were added to the cells and the pH value, ion release and live/dead staining was measured every hour. The effect of BG against bacteria (S. epidermidis) was analyzed after 24 and 72 hours of treatment by using XTT viability assay and CFU counting by plating out the treated aliquot agar to estimate the viable bacteria cells. Results. All three BG compositions tested showed a significant increase in pH, which was highest in BG composition 45S5 with a value of 11 compared to the other BG compositions 10 and 9 in S53P4 and 13-93 respectively. This strong increase in the pH in all BG samples tested results in a strongly reduced cell viability rate of more than 75% compared to the untreated control and 6-fold reduction in bacterial viability compared to the untreated control. The live/ dead assay also showed an increased cell viability with increasing glass particle size (i. e smallest glass particle < 25% viable cell and largest glass particle> 65% viable cell). The ion release concentration over 50 h showed an increase in sodium ions to 0.25 mol/L, calcium to 0.003 mol/L and a decrease in phosphorus. Conclusions. These results show that the composition of the bioactive glass and the choice of particle size have a major influence on subsequent applications. In addition to the different compositions of the BG, particle size and additional medium change also influence the pH and ion release, and therefore also on cells or bacteria viability. The sizes of the bioactive glass particle are inversely proportional to it. Further tests are necessary to develop custom design BG compositions, which simultaneously stimulate osteoblasts proliferation and prevent microbial adhesion

Osteomyelitis is an infectious process in bone occasionally leading to bone destruction. Traditionally a two-stage operation is performed using PMMA + antibiotic beads or a spacer. In the second operation the void filler is removed and the defect is filled with autologous bone. Bioactive glass (BAG) S53P4 is an antibacterial biodegradable bone substitute. This feature is based on an increase in pH and the osmotic pressure around the BAG, a phenomenon which has been shown to kill both planktonic bacteria and bacteria in biofilm in-vitro. We analyzed retrospectively our early results of osteomyelitis patients treated with BAG from the patient's clinical history. The diagnosis was stated in addition to bacterial samples by MRI, CT and plain radiographs or by a combination of these. Between 2007–2013 we applied BAG as a void-filler in 20 cases (15 male and 5 female) of osteomyelitis in the lower (19) or the upper (1) limb in one-stage procedure. The patients had been suffering from symptoms of osteomyelitis a mean 3,5 months (0,25–24,00) and had a history of mean 3,5 (1–11) earlier operations. Osteomyelitis was estimated to be healed when the enclosed systemic antibiotic treatment and clinical controls were carried out and the patient didn't have symptoms of a persisting disease. The average postoperative follow up was 7,8 (3,0–59,0) months. Fifteen (75%) of the patients healed. One patient run out of controls, but was symptom free during his last visit. In four cases we had to remove the bioactive glass because of continuous secretion. In three cases the debridement was incomplete and one had a poor soft tissue cover and a candida infection. Adjuvant systemic antibiotic treatment was prescribed postoperatively 7,3 (4–19) weeks. Bioactive glass is an effective void filling material in the treatment of osteomyelitis. Proper debridement and a soft tissue cover should be performed. Main reason for that the five patients did not heal is, that this procedure is new and we were looking for the right indications and techniques

Chronic osteomyelitis is historically treated in a two stage fashion with antibiotic-loaded polymethylmethacrylate (PMMA) as local antibacterial therapy. However, two-stage surgeries are associated with high morbidity, long hospitalization and high treatment costs. In recent years new biomaterials were developed that allow to change this treatment algorithm. S53P4 bioactive glass is such a novel biodegradable antibacterial bone graft substitute that enables a one-stage surgery in local treatment of chronic osteomyelitis. This study aimed to explore the eradication of infection and bone healing capacities of S53P4 bioactive glass in clinical practice. In this prospective longitudinal outcome study, clinical applicability of S53P4 bioactive glass in treatment of patients with chronic osteomyelitis was assessed. All patients with clinically, haematologically and radiologically evident chronic osteomyelitis were included. All patients were treated with an extensive debridement surgery, S53P4 bioactive glass implantation and systemic antibiotic administration. Primary endpoint of this study is eradication of infection. During follow-up eradication was analysed based on clinical outcomes, blood samples (inflammatory parameters) and radiological outcomes. The secondary endpoint, bone healing, is assessed using conventional radiographic images of the treated region. Between 2011 and 2016, 25 patients were included in this study, with a mean follow-up of 23 months (range 4 – 57). Hospital stay was short with a mean of 18 days (range 4 – 40) and patients required an average of 1,4 surgeries (range 1 – 4). The inflammatory parameter C-reactive protein (CRP) showed a normalization after a mean duration of 46 days (range 0 – 211). At the end of follow-up haematological and clinical outcomes showed eradication of infection in 24 (96%) of all patients. Radiologically none of all patients showed persisting signs of infection and bone healing was observed in 22 (88%) patients based on changes on conventional radiographic images. One patient had a persistent infection without any bone healing, this patient had an infected non-union prior to surgery. There were two other patients with an initial infected non-union fracture which was not consolidated at last follow-up, although they had successful infection treatment. Another patient had a femoral fracture after surgery that needed additional surgery which did not interfere with eradication of infection. Four (16%) of all patients had initial wound healing problems related to compromised skin and/or soft tissue prior to surgery. Based on the results of our clinical experience, S53P4 bioactive glass can successfully be used in a one-stage procedure for treatment of chronic osteomyelitis. Eradication of infection was successful in almost all patients and so far no patients required a second surgery due to infection recurrence. Bone healing (incorporation of the bioactive glass) was seen in all patients except for the patients with an initial infected non-union fracture. As a consequence of these results, we changed our institutional protocol for treatment of chronic osteomyelitis to a one-stage approach instead of a two-step approach

Aims: In a recent study, chemical microroughening of bioactive glass surface was shown to promote attachment of osteoblastic cells and osseointegration of porous bioactive glass implant. The current in vivostudy employed molecular biologic techniques to clarify the osteogenic effects of smooth and microrough glass surfaces. Methods:Using a rat model, a portion of the medullary canal in the proximal tibia was evacuated and filled with microroughened or smooth bioactive glass microspheres. The primary bone healing response and subsequent remodelling were analysed at 1, 2, and 8 weeks, respectively. The expression of various genes for the bone matrix components (type I collagen, osteocalcin, osteopontin, osteonectin) and proteolytic enzymes (cathepsin K, MMP-9) were determined by Northern analysis. Results: The microroughened bioactive glass microspheres were found to induce higher mRNA levels for osteopontin and lower levels for osteonectin at 2 weeks after operation when compared to smooth control micropheres. At 8 weeks, the MMP-9 expression levels were significantly higher with microroughened bioactive glass microspheres. Conclusion: Microroughening of the bioactive glass surface triggered temporal changes in the expression of specific genes

Aims: Bioactive glasses are a family of silica-based synthetic biomaterials, which form chemical bonding with the surrounding bone. The limiting biologic factors of the bonding process are poorly understood. The hypothesis of the current study was that there are species-specific differences in the incorporation of bioactive glasses due to anatomic and physiologic factors. Methods: Conical porous implants made of sintered bioactive glass or titanium microspheres (Ø 250–300 μm) were surgically implanted bilaterally into the cortex of tibias or femurs in sheep, dog and rabbit. Implant incorporation was evaluated by means of push-out testing, pQCT, his-tomorphometry, BEI-SEM, and EDXA. The comparison was made at 12 weeks. A total of 176 implants were analysed. Results: Between the three species, there were significant differences in the extent of new bone ingrowth and in the mechanical strength of implant fixation. The rabbit showed the highest amount of bone ingrowth into both bioactive glass and titanium implants. Also the shear strength of the implants was superior in the rabbit compared with the dog and the sheep. Histological pattern of new bone ingrowth into bioactive glass structures was similar in the dog and in the rabbit. In contrast, the ingrowth of new bone failed into bioactive glass implants in the sheep. Conclusions: Based on these results, the sheep represents a divergent model for bone healing studies of bioactive glass. Long bones of the sheep contain yellow (fat) marrow and we assume that the poor healing response reflects the deficiency of marrow-derived osteoprogenitor cells

The bone infection osteomyelitis (typically Staphylococcus aureus) requires a multistep treatment process including: surgical debridement, long-term systemic high-dose antibiotics, and often bone grafting. With antibiotic resistance becoming increasingly concerning, alternative approaches are urgently needed. Herein, we develop a one-step treatment for osteomyelitis that combines local, controlled release of non-antibiotic antibacterials (copper) within a proven regenerative scaffold. To maximise efficacy we utilised bioactive glass – an established material with immense osteogenic capacity – as a copper ion delivery reservoir. Copper ions have also been shown to stimulate angiogenesis and induce MSC differentiation down an osteogenic lineage. To eliminate grafting requirements, the copper-doped BG was incorporated into our previously developed collagen scaffolds to produce multifunctional antibacterial, osteogenic, and angiogenic scaffolds. Scaffolds were fabricated by freeze-drying a co-suspension of collagen and bioactive glass particles (+/− copper doping, referred to as CuBG and BG, respectively) at a range of different concentrations (0–300% w/w bioactive glass/collagen). Scaffolds demonstrated a 2.7-fold increase in compressive modulus (300% CuBG vs. 0%; p≤0.01), whilst maintaining >98% porosity. The 300% CuBG scaffolds showed significant antibacterial activity against Staphylococcus aureus (p≤0.001). In terms of osteogenesis, both 100% and 300% CuBG scaffolds increased cell-mediated calcium deposition on the scaffolds at day 14 and 28 (p≤0.05 and p≤0.001), as confirmed by alizarin red staining. 100% CuBG scaffolds significantly enhanced angiogenesis by increased tubule formation (p≤0.01) and VEGF protein production (p≤0.001) (all ≥n=3). In summary, this single-stage, off-the-shelf treatment for osteomyelitis shows potential to minimise bone grafting and antibiotic dependence, while reducing hospital stays and costs

Introduction. Articular cartilage has a low self-regeneration capacity. Cartilage defects have to be treated to minimize the risk of the onset of osteoarthritis. Bioactive glass (BG) is a promising source for cartilage tissue engineering. Until now, conventional BGs (like BG1393) have been used, mostly for bone regeneration, as they are able to form a hydroxyapatite layer and are therefore, less suited for cartilage reconstruction. The aim of this study is to study the effect of 3D printed hydrogel scaffolds supplemented with spheres of the BG CAR12N to improve the chondrogenesis of mesenchymal stem cells (MSCs). Method. Based on our new glass composition (CAR12N), small BG spheres (25-40 µm) were produced and mixed with hydrogel and primary human (h) MSCs. Grid printed scaffolds were cultivated up to 21 days in expansion or chondrogenic differentiation medium. Macroscopical images of the scaffolds were taken to observe surface changes. Vitality, DNA and sulfated glycosaminoglycan (GAG) content was semiquantitatively measured as well as extracellular matrix gene transcription. Result. It was possible to print grid shaped hydrogel scaffolds with BG spheres and hMSCs. No significant changes in scaffold shape, surface or pore size were detected after 21 days in culture. The BG spheres were homogeneously distributed inside the grids. Vitality was significantly higher in grids with CAR12N spheres in comparison to those without. The DNA content remained constant over three weeks, but was higher in the sphere containing scaffolds than in those without BG spheres. GAG content in the grids increased not only with additional cultivation time but especially in grids with BG spheres in chondrogenic medium. Aggrecan and type II collagen gene expression was significantly higher grids cultured in the chondrogenic differentiation medium. Conclusion. This developed 3D model, is very interesting to study the effect of BG on hMSCs and to understand the influence of leaking ions on chondrogenesis

Aims: We wanted to compare bioactive glass granules with autogenous bone in operative treatment of lateral condyle fractures. Methods: 25 patients, 12 females and 13 males, (from 36 to 69 years) were operated at our institute for lateral condyle fracture. The patients were randomized into autogenous bone (AB) and bioactive glass (BG) group. There were no statistical difference between the two groups with regard to genre, patient age, type of fracture or comminution and depression of the joint surface. The study protocol was approved by the local hospital ethical committee and written consent of the patients was achieved. A routine AO operation protocol was used in all patients. Prior to operation plain x-ray þlms and three-dimensional computed tomography (3D CT) was performed in order to reveal the anatomy of the fracture. The postoperative follow-up included 3D CT, plain þlms and clinical examination after the operation and at 6 weeks, 3, 6, 12 and 36 months. Results: The mean preoperative articular depression in the BG group was 9 mm (±4 mm) and in the AB group 7mm (±2 mm). Postoperatively the articular surface remained 2 mm (± 3 mm) depressed in both groups. Threafter the articular height remained unchanged. As evaluated by CT and plain þlms the bioactive glass granules were incorporated with the surrounding bone at 3 months. No adverse reactions due to bioactive glass were observed. The clinical results were equal in both groups. Conclusions: The clinical and radiological results using bioactive glass were as good as those when autogenous bone was used

The regenerative capacity of hyaline cartilage is greatly limited. To prevent the onset of osteoarthritis, cartilage defects have to be properly treated. Cartilage, tissue engineered by mean of bioactive glass (BG) scaffolds presents a promising approach. Until now, conventional BGs have been used mostly for bone regeneration, as they are able to form a hydroxyapatite (HA) layer and are therefore, less suited for cartilage reconstruction. The aim of this study is to compare two BGs based on a novel BG composition tailored specifically for cartilage (CAR12N) and patented by us with conventional BG (BG1393) with a similar topology. The highly porous scaffolds consisting of 100% BG (CAR12N, CAR12N with low Ca2+/Mg2+ and BG1393) were characterized and dynamically seeded with primary porcine articular chondrocytes (pACs) or primary human mesenchymal stem cells (hMSCs) for up to 21 days. Subsequently, cell viability, DNA and glycosaminoglycan contents, cartilage-specific gene and protein expression were evaluated. The manufacturing process led to a comparable high (over 80%) porosity in all scaffold variants. Ion release and pH profiles confirmed bioactivity for them. After both, 7 and 21 days, more than 60% of the total surfaces of all three glass scaffold variants was densely colonized by cells with a vitality rate of more than 80%. The GAG content was significantly higher in BG1393 colonized with pACs. In general, the GAG content was higher in pAC colonized scaffolds in comparison to those seeded with hMSCs. The gene expression of cartilage-specific collagen type II, aggrecan, SOX9 and FOXO1 could be detected in all scaffold variants, irrespectively whether seeded with pACs or hMSCs. Cartilage-specific ECM components could also be detected at the protein level. In conclusion, all three BGs allow the maintenance of the chondrogenic phenotype or chondrogenic differentiation of hMSCs and thus, they present a high potential for cartilage regeneration

The rationale for a degradable bioactive glass coating is to lead the bone to appose gradually to the metal without the release of non-degradable particles. Two formulations of bioactive glasses, already described in the literature, have been studied: bg A and bg F. A non-bioactive glass (glass H) was sprayed as a control. Glass-coated Ti6Al4V cylinders were implanted in the femoral canal of New Zealand White rabbits. Samples were analysed by back scattered electron microscopy (BSEM) and electron dispersive analysis (EDX). Bone was in tight apposition with the coating. As time progressed, images were found where bone showed features of physiological remodelling (newly formed bone filling areas of bone resorption) close to the coating. At the interface the apposition was so tight that it was not possible to discern a clear demarcation, even at higher magnification (more than 2500x). There was a gradual degradation during time and at 10 months bone was found apposed directly to the metal in more than half of the samples. In contrast, the non-bioactive glass coating showed complete integrity at any time examined and a clear demarcation with the coating was evident. Two peculiar features of the behaviour of bioactive glass coatings in vivo are: (a) degradation during time; and (b) promotion of a tight apposition with the newly formed bone

Introduction: New biological approaches to reconstruction of major bone deficiency such as the use of bone substitutes and growth factors are being developed. This paper reports on the adverse response to the Bioglass in comparison to allograft alone. Aim: To compare the biological response to femoral impaction grafting and a cemented femoral stem when using allograft bone versus allograft bone plus a synthetic bone graft substitute, Bioactive glass. Methods: Eighteen merino wethers underwent a left cemented hemi-arthroplasty and were randomised to have impaction allografting of the femur using either allograft alone (allograft group) or a 50:50 mix of allograft and Bioactive glass (Bioglass group). After sacrifice at 12 weeks, histological analysis of the femora at the levels of the proximal, mid and distal femoral stem and distal to the stem was undertaken. Results: In the allograft group, there was a consistent response with bone graft incorporation being greatest in the proximal femur and occurring progressively less, more distally. Mineralised bone apposition in the graft occurred post-operatively after eight weeks. In contrast, in the Bioglass group, the response was inconsistent. Bone graft incorporation was either minimal, or there was partial or complete resorption of the bone graft with replacement by particulate-laden fibrous tissue and resorption of endocortical bone. Inflammation of the capsule tissue was noted in some cases. Conclusion: In comparison to allograft alone, the use of Bioglass to supplement allograft for use in impaction grafting in ovine hip arthroplasty gave inferior results

The treatment of chronic osteomyelitis often includes surgical debridement and filling the resultant void with antibiotic-loaded polymethylmethacrylate cement, bone grafts or bone substitutes. Recently, the use of bioactive glass to treat bone defects in infections has been reported in a limited series of patients. However, no direct comparison between this biomaterial and antibiotic-loaded bone substitute has been performed. . In this retrospective study, we compared the safety and efficacy of surgical debridement and local application of the bioactive glass S53P4 in a series of 27 patients affected by chronic osteomyelitis of the long bones (Group A) with two other series, treated respectively with an antibiotic-loaded hydroxyapatite and calcium sulphate compound (Group B; n = 27) or a mixture of tricalcium phosphate and an antibiotic-loaded demineralised bone matrix (Group C; n = 22). Systemic antibiotics were also used in all groups. After comparable periods of follow-up, the control of infection was similar in the three groups. In particular, 25 out of 27 (92.6%) patients of Group A, 24 out of 27 (88.9%) in Group B and 19 out of 22 (86.3%) in Group C showed no infection recurrence at means of 21.8 (12 to 36), 22.1 (12 to 36) and 21.5 (12 to 36) months follow-up, respectively, while Group A showed a reduced wound complication rate. Our results show that patients treated with a bioactive glass without local antibiotics achieved similar eradication of infection and less drainage than those treated with two different antibiotic-loaded calcium-based bone substitutes. Cite this article: Bone Joint J 2014; 96-B:845–50

Introduction and Objective. Regeneration of cartilage injuries is greatly limited. Therefore, cartilage injuries are often the starting point for later osteoarthritis. In the past, various bioactive glass (BG) scaffolds have been developed to promote bone healing. Due to the fact that they induce the deposition of hydroxyapatite (HA) -the main component of bone matrix, these BG types are not suitable for chondrogenesis. Hence, a novel BG (Car12N) lacking HA formation, was established. Since BG are generally brittle the combination with polymers is helpful to achieve suitable biomechanic stability. The aim of this interdisciplinary project was to investigate the effects of biodegradable polymer Poly(D,L-lactide-co-glycolide) (PLLA) infiltration into a Car12N scaffold for cartilage tissue engineering. Materials and Methods. BG scaffolds were infiltrated with PLLA using phase separation within a solvent. Pure BG Car12N scaffolds served as control. To assess whether the polymer was homogeneously distributed the polymer to glass ratio and pore contents in the upper, middle and lower third of the scaffolds were examined by light microscopy. For a more precise characterization of the scaffold topology, the glass strut length, the glass strut diameter and the pore circumference were also measured. Leaching tests in 0.1M HCl solution over 8 days were used to allow a gel layer formation on the scaffolds surface. Non-leached and leached scaffolds were subjected to strength testing. Cytotoxicity of the scaffolds with and without polymer was tested according to standards. Scaffolds were colonized with 27.777.8 per cm. 3. primary porcine articular chondrocytes (pACs) or primary human mesenchymal stromal cells (hMSCs), respectively. After cultivation for up to 35 days, the vitality, quantitative DNA and sulfated glycosaminoglycan (sGAG) contents per scaffold were determined. Results. The polymer distribution was not homogeneous in the scaffolds. There were significant differences in glass strut length and pore size. Leaching increased the biomechanical strength. All scaffolds were not cytotoxic. pACs and hMSCs were able to adhere to the scaffold with and without polymer and remained viable during the whole culturing period of 35 d. The DNA content was higher in the pAC colonized scaffolds with polymer than without polymer. The sGAG content was higher in hMSCs seeded scaffolds with polymer than in pACs seeded ones with polymer. Conclusions. Polymer infiltration leads to an increase in mechanical stability of Car12N scaffolds and chondrogenic cells are able to colonize these composites suggesting them as a promising

Aims: The present study examined the effect of ade-novirus-mediated recombinant human BMP-2 (RAd-BMP-2) gene therapy combined with bioactive glass (BG) microspheres in promotion of new bone formation. Methods: Harlan Dawley female rats (n=72) underwent unilateral surgery of right or left tibia in a random order. A round cortical window (. −. 2.8 mm) was drilled into the anteromedial cortex of the proximal tibia. A smaller unicortical hole (. −. 1.0 mm) was drilled 5 mm distally. Bone marrow was removed and the medullary space between the cortical holes was þlled with BG microspheres. Adenoviral vectors RAdBMP-2 carrying the BMP-2 gene or RAdLacZ harbouring the E. coli LacZ reporter gene were injected locally into the medullary spaces. The control defects were þlled with BG microspheres only. Empty control defects were left to heal without any þlling. The rats were killed 4 days, 2 and 8 weeks after surgery and the tibias were harvested for analyses. At each time point, six animals were used for pQCT, radiography, BEI-SEM and histomorphometric analyses. Results: All BG-þlled defects showed a time-related increase of intramedullary new bone. At 8 weeks, there was signiþcantly more new bone in defects treated with BG and RAdBMP-2 gene than in defects left to heal without þlling (p=0.003) (BG + RAdBMP-2: 25.0 ± 6.0% and empty control defects: 12.3 ± 3.8%). Also defects þlled with BG only showed higher new bone formation than empty control defects, but this was not statistically signiþcant (p=0.10) (BG: 19.9 ± 7.3%). Conclusions: The current study showed that local BMP-2 gene therapy enhances new bone formation on bioactive glass microspheres

Aim. We aimed to compare the in vitro antibacterial activity of Bioactive Glass (BAG) S53P4, which is a compound showing local antibacterial activity, to that of antibiotic-loaded polymethylmethacrylate (PMMA) against multidrug resistant bacteria from osteomyelitis (OM) and prosthetic joint infection (PJI) isolates. Method. We studied convenience samples of multidrug resistant (MDR) microorganisms obtained from patients presenting OM and prosthetic joint infection (PJI). Mixtures containing tryptic soy broth (TSB) and inert glass beads (2mm), BAG-S53P4 granules (0.5–0.8mm and <45 mm) and Gentamicin or Vancomycin-loaded PMMA beads were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus (MR-CoNS), Pseudomonas aeruginosa or Klebsiella pneumoniae isolates. Glass beads (2.0mm) were used as a control. Antibacterial activity was evaluated by means of time-kill curve, through seeding the strains on blood agar plates, and subsequently performing colony counts after 24, 48, 72, 96, 120 and 168 hours of incubation. Differences between groups were evaluated by means of two-way analysis of variance (ANOVA) and Bonferroni's t test. Results. Inhibition of bacterial growth started soon after 48 hours of incubation, reached zero CFU/ml between 120 and 168 hours of incubation for both antibiotic-loaded PMMA and BAG S53P4 groups, in comparison with inert glass (p< 0.05). No difference regarding time-kill curves between antibiotic-loaded PMMA and BAG S53P4 was observed. Moreover, despite no difference was observed between both Vancomycin - or Gentamicin-loaded PMMA and BAG groups, there was statistical difference between the effectiveness of all treatments (BAG included) against gram-positive cocci and gram-negative bacilli, the latter of which requiring longer time frames for the cultures to yield no bacterial growth. Conclusions. BAG S53P4 presented antibacterial properties as much as antibiotic-loaded PMMA for MDR bacteria producing OM and PJI, although presenting differences between its effectiveness against different bacterial groups

Hydrogels as scaffolds provide a suitable environment for the cells (biocompatibility, biodegradability). Their biomechanical properties are very important to provide not only direct support to the surrounding tissue but also provide a local microenvironment. There is an interest in composite hydrogels with hydroxylapatite or bioactive glass (BAG) for tuning of their bioactivity and biomechanical properties [1]. Hydrogels were prepared from a polysaccharide gellan gum (GG), dissolved in ultrapure water at 90°C under constant stirring to a final concentration of 2 wt.% GG. Sodium-free BAG (70 wt.% SiO. 2. , 30 wt.% CaO) was synthesized using a sol-gel technique with particles of ∼100 nm, clustered to ∼10 µm large agglomerates [1]. The hydrogel composites were prepared by admixing up to 2–8 wt.% of BAG powder into a solution of GG during sonication, and pouring the hot BAG-GG suspension with following cooling to room temperature. Mechanical properties were evaluated using different protocols in creep (0.1 to 1.2 N), strain sweep (1 to 20 µm) and frequency scan (100 to 0.1 Hz) modes, with specimens immersed in water at 25°C. Maximum load (or deformation) before breaking of scaffold materials is a very important material property but is rarely measured. Here creep experiments at different applied stresses were carried out first. These loads exert more proper stress on the scaffold material that results in deformation, which is not the same as during deformation in relaxation or stress-strain tests [2]. The second set of experiments was made at physiologically relevant conditions (1 Hz frequency and small amplitude-controlled deformation) [3]. Amount of 2% BAG was found to be sufficient to get nearly linear deformation in the whole measured strains region, but at higher concentration stress deviated from linearity at strains exceeding ∼0.5% at 1 Hz. Storage modulus (E') did not significantly change and the loss tangent was found nearly constant (∼0.1) for the whole frequency range, indicating a strong network structure of BAG-doped hydrogel. Additions of 2% BAG give a ten-fold increase in both storage and loss moduli, whereas further increase of BAG content does not show further stiffening. The application of tailored protocols [3] allowed analysis of dynamic, creep and relaxation tests in the same device with same specimens, which might be not possible for other techniques. Creep data would provide valuable information in addition to dynamic modes to predict long-term behaviour of the composite hydrogels. Properly tailored protocols could mimic, for example, articular cartilage or other tissue working conditions and allow evaluation of the side effects like swelling at early stage, which measurements are usually rather cumbersome

Introduction

Bioactive glasses (BGs) promote osteogenic differentiation of bone progenitor cells by releasing therapeutically active ions. The well-described 45S5-BG (in mol%: SiO₂ 46.13; P₂O₅ 2.60; CaO 26.91; Na₂O 24.35) was supplemented with CaF₂ and NaF being added to the batch at nominal 5 (F5-BG) and 25 mol% (F25-BG), respectively. While the effect on physical and chemical properties has already been characterized, the biological properties require further studies. This study investigates the effects of fluoride-supplemented BGs on the osteogenic and angiogenic properties of human bone marrow mesenchymal stromal cells (BMSCs) in vitro.

Background

Bio-Active Glass (BAG) is a promising bone graft substitute for large bone defect reconstruction because of its favourable osteoconductive, antibacterial and angiogenic properties. Potentially, it could also mechanically reinforce the defect, thus making it suitable for load-bearing defects. However, the mechanical properties of the reconstructive layer consisting of BAG/bone allograft mixtures are unknown. The goals of this study therefore were, first, to measure the mechanical properties of different BAG/bone graft mixtures and, second, to investigate to what extent such mixtures could reinforce distal tibial defects using micro-FE analysis and high-resolution CT scans.