Miniscrew implants (MSIs) are widely used to provide absolute anchorage for the orthodontic treatment. However, the application of MSIs is limited by the relatively high failure rate (22.86%). In this study, we wished to investigate the effects of amorphous and crystalline biomimetic calcium phosphate coating on the surfaces of MSIs with or without the incorporated BSA for the osteointegration process with an aim to facilitate the early loading of MSIs. Amorphous and crystalline coatings were prepared on titanium mini-pin implants. Characterizations of coatings were examined by Scanning electron microscopy (SEM), Confocal laser-scanning dual-channel-fluorescence microscopy (CLSM) and Fourier-transform infrared spectroscopy (FTIR). The loading and release kinetics of bovine serum albumin (BSA) were evaluated by Enzyme linked immunosorbent assay (ELISA). Activity of alkaline phosphate (ALP) was measured by using the primary osteoblasts. In vivo, a model of metaphyseal tibial implantation in rats was used (n=6 rats per group). We had 6 different groups: no coating no BSA, no coating but with surface adsorption of BSA and incorporation of BSA in the biomimetic coating in the amorphous and crystalline coatings. Time points were 3 days, 1, 2 and 4 weeks. Histological and histomorphometric analysis were performed and the bone to implant contact (BIC) of each group was compared. In vitro, the incorporation of BSA changed the crystalline coating from sharp plates into curly plates, and the crystalline coating showed slow-release profile. The incorporation of BSA in crystalline coating significantly decreased the activity of ALP in vitro. In vivo study, the earliest significant increase of BIC appeared in crystalline coating group at one week. The crystalline coating can serve as a carrier and slow release system for the bioactive agent and accelerate osteoconductivity at early stage in vivo. The presence of BSA is not favorable for the early establishment of osteointegration

Over the last decades, biodegradable metals emerged as promising materials for various biomedical implant applications, aiming to reduce the use of permanent metallic implants and, therefore, to avoid additional surgeries for implant removal. However, among the important issue to be solved is their fast corrosion - too high to match the healing rate of the bone tissue. The most effective way to improve this characteristic is to coat biodegradable metals with substituted calcium phosphates. Tricalcium phosphate (β-TCP) is a resorbable bioceramic widely used as synthetic bone graft. In order to modulate and enhance its biological performance, the substitution of Ca2+ by various metal ions, such as strontium (Sr2+), magnesium (Mg2+), iron (Fe2+) etc., can be carried out. Among them, copper (Cu2+), manganese (Mn2+), zinc (Zn2+) etc. could add antimicrobial properties against implant-related infections. Double substitutions of TCP containing couples of Cu2+/Sr2+ or Mn2+/Sr2+ ions are considered to be the most perspective based on the results of our study. We established that single phase Ca3−2x(MˊMˊˊ)x(PO4)2 solid solutions are formed only at x ≤ 0.286, where Mˊ and Mˊˊ—divalent metal ions, such as Zn2+, Mg2+, Cu2+, Mn2+, and that in case of double substitutions, the incorporation of Sr2+ ions allows one to extend the limit of solid solution due to the enlargement of the unit cell structure. We also reported that antimicrobial properties depend on the substitution ion occupation of Ca2+ crystal sites in the β-TCP structure. The combination of two different ions in the Ca5 position, on one side, and in the Ca1, Ca2, Ca3, and Ca4 positions, on another side, significantly boosts antimicrobial properties. In the present work, zinc-lithium (Zn-Li) biodegradable alloys were coated with double substituted Mn2+/Sr2+ β-TCP and double substituted Cu2+/ Sr2+ β-TCP, with the scope to promote osteoinductive effect (due to the Sr2+ presence) and to impart antimicrobial properties (thanks to Cu2+ or Mn2+ ions). The Pulsed Laser Deposition (PLD) method was applied as the coating's preparation technique. It was shown that films deposited using PLD present good adhesion strength and hardness and are characterized by a nanostructured background with random microparticles on the surface. For coatings characterization, Fourier Transform Infrared Spectroscopy, X-ray Diffraction, and Scanning Electron Microscopy coupled with Energy Dispersive X-ray and X-ray Photoelectron Spectroscopy were applied. The microbiology tests on the prepared coated Zn-Li alloys were performed with the Gram-positive (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative (Salmonella typhimurium, Escherichia coli) bacteria strains and Candida albicans fungus. The antimicrobial activity tests showed that Mn2+/Sr2+ β-TCP -coated and Cu2+/Sr2+ β-TCP coated Zn-Li alloys were able to inhibit the growth of all five microorganisms. The prepared coatings are promising in improving the degradation behavior and biological properties of Zn-Li alloys, and further studies are necessary before a possible clinical translation

Summary Statement. The problem facing this research is to promote rapid osteointegration of titanium implants and to minimise the risks of infections by the functionalization with different agents, each designed for a specific action. A patented process gives a multifunctional titanium surface. Introduction. A patented process of surface modification is described. It gives a multifunctional surface with a multiscale roughness (micro and nano topography), that is excellent for osteoblast adhesion and differentiation. It has a high degree of hydroxylation, that is relevant for inorganic bioactivity (apatite-HA precipitation) and it is ready for a functionalization with biological factors. A direct grafting of ALP has been obtained. Moreover, the growth of an antibacterial agent within the surface oxide layer can be useful in order to combine the osteoinduction ability to antimicrobial effects. The selection of an inorganic agent (metal nanoparticles) has the advantage to avoid an eventual development of antibiotic resistance by bacteria. Experimental Methods. Ti-cp and Ti6Al4V samples were polished or blasted, etched in diluted hydrofluoric acid (step 1a), oxidised in hydrogen peroxide (step 1b), incubated in Tresyl chloride (step 2a) and Alkaline phosphatase (ALP) enzyme (step 2b) [1, 2]. A water solution, containing a salt of the metal to be added to the surface as an inorganic antibacterial agent, can be introduced during the oxidation in hydrogen peroxide. Surface morphology and chemical composition were investigated by Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) equipped with Energy Dispersive Spectroscopy (EDS). The composition of the outermost surface layer and the chemical state of elements were analyzed by X-Ray Photoelectron Spectroscopy (XPS). The activity of grafted enzyme was studied by an enzymatic activity test. In vitro bioactivity was evaluated by soaking the samples in simulated body fluid and SEM observation to verify hydroxyapatite (HA) precipitation. Antibacterial activity has been determined by inhibition halo test against S aureus. Results and Discussion. A peculiar multi-scale topography, with spongy-like nanometric features, was obtained after the inorganic treatment (step 1a-1b). This morphology can be superimposed on the micro-or macro roughness deriving from acid etching or blasting, by properly optimizing the process parameters. Moreover, the treated surfaces present a high density of hydroxyl groups (XPS data) and they are bioactive (HA precipitation after soaking in SBF for 15 days). Metal (Ag, Cu, Zn) nanoparticles can be grown within the surface oxide layer and they are effective as antimicrobial inorganic agents. The amount of the metal nanoparticles can be tailored in order to have an antibacterial or a bacteriostatic surface. The effective grafting of ALP (step 2a-2b) has been shown by XPS because of the appearance of characteristic peaks in the carbon region. Moreover, it has been observed that ALP maintains its activity after grafting by an enzymatic activity test. ALP grafting improves HA precipitation kinetics. Conclusions. An innovative process was applied to titanium surfaces in order to obtain a better bone integration ability and antibacterial activity. A multi scale surface topography (micro and nano features) was successfully obtained together with an high hydroxylation degree. Modified surfaces are able to induce hydroxyapatite precipitation in vitro and to graft ALP, maintaining its activity and improving bioactivity. Metal nanoparticles embedded in the surface oxide layer have an antibacterial effect

Meniscus has many important functions in the knee joint such as load bearing, shock absorption, joint stability, joint lubrication and proprioception. In the recent years, meniscus injuries have been the focus of orthopaedic surgeons and musculoskeletal tissue engineering applications because of its avascular nature. In this study, we aimed to compare the regeneration capacities of two composite scaffolds in a New Zealand Rabbit meniscal defect model. The first scaffold consists Poly-Lactic Acid (PLA) + chitosan + loofah and the second PLA + Hydroxyapatite (HAp) + loofah. In order to produce these scaffolds; 4% chitosan, 4% PLA and 4% HAp solutions were seperately prepared. The loofah pieces were saturated with these solutions and vacuum-dried for 14 days and sterilized with ethylene oxide. There were several characterizations performed such as Fourier Transform Infrared Spectroscopy (FTIR) for the investigation of chemical structure, Scanning Electron Microscopy (SEM) for morphological analysis, thermogravimetric differential thermal analysis (TGA/DTA) for thermal properties, mechanical compression and swelling ratio analysis. Moreover, in order to investigate biocompatibility of the scaffolds, WST-1 colorimetric assay at days 3, 7, 10, 14 and 21 was conducted. After these biocompatibility analysis, a 1.5-mm cylindrical defect was created in the avascular portion of the anterior horn of the medial meniscus in 14 New Zealand rabbits (2.5–3 kg weight) which were randomly grouped in two. The scaffolds were implanted at the defect site with the help of a freshly prepared fibrin glue. 8 weeks after the operation, the rabbits were sacrificed and their tissues were kept for further mechanical, radiological and histological analysis. In conclusion, we succeeded to produce a new meniscus scaffold. The proliferation ability of PLA + chitosan + loofah scaffold is higher than PLA + HAp + loofah scaffold. However, there was no statistically significant difference among them

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

Total ankle replacement (TAR) has a mean survivorship of 77% at 10 years which is poor compared to other types of joint arthroplasty. Osteolysis and aseptic loosening are commonly cited TAR failure modes, the mechanisms of which are unknown. Retrieval analyses of TAR devices may reveal mechanisms of failure similar or dissimilar to other joint replacements. This study investigated whether TAR explants exhibit similar damage modes to those recognised in other total joint replacements. 22 Ankle Evolution System TARs (Transystème, Nimes, France) were implanted and retrieved by the same surgeon. Mean implantation time was 7.8 yrs (5.3 to 12.1 range). Pain and/or loosening were the indications for revision. Macro photography, an Alicona Infinite microscope and the Hood/Wasielewski scale were used to classify damage modes on the polyethylene insert. Scanning electron microscopy with energy dispersive X-ray spectroscopy was used to determine the composition of third body debris and to image the fixation surface of the tibial components. Mean damage score was 185.4 (± 40.0 SD). Damage modes common to total knee replacements were identified on both the superior and inferior insert surfaces, these included: burnishing, scratching, pitting and abrasion. Titanium particles, hydroxyapatite fragments and bone debris were embedded in the insert surfaces. Fixation surface delamination was identified by the ongrowth of tissue between the cobalt chromium substrate and titanium alloy coating. Damage modes indicative of high levels of wear and deformation were evident. Pitting caused by third body debris was abundant and suggested fixation surface wear and failure

Introduction. Millions of bone graft surgeries have improved the quality of the life of millions, which cost about £ 2.5 billion annually worldwide. Current focus of the researcher is to synthesis of a bioactive bone scaffold which will reduce the cost and number of the bone graft surgeries. Hypothesis To synthesis novel, bioactive, porous, mechanical stable bone scaffold using bio glass and alginate. Methods. Sr releasing glass was made using by melt derived technique. Composite bone scaffold was made using bio-glass and alginate. Freeze dry technique was used to make the porous bone scaffold. Bone scaffold was characterized using XRD, DSC, FTIR, Particle size analyser, SEM, ICP, Mechanical testing, Cell culture with osteoblast and fibroblast and NMR techniques. RESULTS. Fig: Graph showing the FTIR spectra of bone scaffold. Discussion and conclusion. FTIR shows the Si-o-Si bonds of the glass and shifting of the bonding after adding the alginate and during cross linked with Cacl2 and Srcl2. Scanning electron microscopy result shows the average pore size of around 100µm which is desirable for the growth of the cell. Release of desirable Calcium and phosphate ions can be seen from the ICP-OES measurement. Compression test allows deciding that the composite material with alginate and bioactive glass shows much better result than the simple alginate scaffolds. Cell culture showed round cells on the surface of the scaffold. And the NMR shows the interaction between bio glass and alginate. Significance We were able to produce a new novel bone scaffold which can reduce the economical burden of bone grafting

Background. Aseptic loosening remains the primary reason for failure of orthopaedic implants. Therefore a prime focus of Orthopaedic research is to improve osteointegration and outcomes of joint replacements. The topography of a material surface has been shown to alter cell adhesion, proliferation and growth. The use of nanotopography to promote cell adhesion and bone formation is hoped to improve osteointegration and outcomes of implants. We have previously shown that 15nm high features are bioactive. The arrangement of nanofeatures has been shown to be of importance and block-copolymer separation allows nanopillars to be anodised into the titania layer, providing a compromise of control of order and height of nanopillars. Osteoblast/osteoclast stem cell co-cultures are believed to give the most accurate representation of the in vivo environment, allowing assessment of bone remodelling related to biomaterials. Aims. To assess the use of nanotopography on titania substrates when cultured in a human bone marrow derived co-culture method. Hypothesis. Under co-culture conditions 15nm high nanopillars on titania substrate will induce significantly increased levels of osteogenic differentiation, producing a method of enhancing secondary implant fixation. Methods/Design. Bone marrow was aspirated from patients undergoing elective arthroplasty. Co-culture of adherent osteoprogenitors and osteoclast progenitors on polished titania and titania patterned with 15nm nanopillars fabricated by the block copolymer technique was performed. Histochemical staining has been performed to identify and quantify osteoclasts and bone nodule formation. Scanning electron microscopy (SEM) has been conducted to morphologically examine the effect on differentiation of untreated and nanopatterned titania substrates on osteoprogenitors and osteoclasts. Real-Time, quantitative reverse-transcription polymerase chain reaction is currently being utilised to quantify expression of osteoblast, osteoclast and inflammatory response related genes. Results. SEM has shown an increase in bone deposition on titania substrates with 15nm nanopillars. The remaining results of this project will be presented with a discussion of their clinical significance

Bone grafting utilises tissue harvesting from second anatomic location of same patient (autograft) or from a human donor (allograft) to treat bone defects. Limited availability of bone grafts, donor site morbidity and risk of disease transmission led to an alternative strategy for bone grafting as synthetic materials that can promote bone regeneration. Engineered bone grafts are biocompatible and possess sufficient mechanical strength to support fractured bone. Polymer scaffolds lack mechanical stability whereas ceramic scaffolds are stiffer resulting in loosening of implants. Combining polymer and ceramic to form scaffolds can enhance the physical and mechanical properties and can be used for bone tissue engineering. We hypothesised that the nucleation of hydroxyapatite in carboxymethyl cellulose (CMC) matrix would improve scaffold properties physically and mechanically; thus, demonstrating CMC based biomimetic process to synthesise novel CMC/ HA scaffolds with suitable physical, mechanical and biological properties for bone tissue engineering. CMC/ HA scaffolds were synthesized by in situmethod at room temperature (RT) and 60°C and are labelled as CHRT and CH60 respectively, keeping the molar ratio of Ca/P as constant ∼1.6. The nucleation of hydroxyapatite (HA) from calcium chloride (CaCl. 2. ) and sodium dihydrogen phosphate (NaH. 2. PO. 4. ) was initiated inside carboxymethyl cellulose (CMC). CaCl. 2. solution was introduced gently in aqueous solution of CMC, thereafter; NaH. 2. PO. 4. solution was added dropwise and the mixture was stirred vigorously, kept overnight for aging at RT to obtain milky white slurry. The slurry was washed with distilled water to neutralize, cast into moulds and dried in hot air oven for 72 h to obtain scaffolds. Scanning electron microscopy (SEM) was performed to determine the surface topography of the scaffolds. Mechanical properties were tested with Universal Testing Machine (UTM) and cytotoxicity was performed by MTT assay using fibroblast cells (NIH 3T3). SEM images shows that HA aggregates like beads and knitted orderly over CMC backbone. There is an increase in HA agglomerates and decrease in bead size with increase in synthesis temperature from RT to 60°C. Scaffolds synthesized at 60°C show enhanced mechanical properties. Compressive strength of CHRT and CH60 are 0.68 MPa and 0.9 MPa respectively and compressive moduli of CHRT and CH60 are 33 MPa and 69 MPa respectively. MTT assay confirmed proliferation of fibroblast cells, hence; proved the non-toxic nature of the scaffolds. MTT assay reveals the cell viability (cell exoskeleton) on the scaffolds after 24 h incubation. In this study, CMC/ HA scaffolds were synthesised by in situmethod at RT and 60°C. Enhanced mechanical properties and cytocompatibility reveal the potentiality of the scaffolds for bone tissue engineering purposes

Among plant derived molecules, polyphenols have antioxidant, anticancer and antibacterial ability [1,2]. Moreover, they can stimulate osteoblast differentiation and promote apoptosis of tumoral cells [3–4]. It's thus possible combine the properties of these molecules with those of bioactive materials trough surface functionalization. A silica-based bioactive glass and chemically treated bioactive Ti6Al4V were used as substrates while gallic acid and polyphenols extracted from green tea or red grape skin as biomolecules for functionalization. The surface functionalization procedure was optimized in order to maximize the grafting and investigated by means of the Folin&Ciocalteu method and X-Ray Photoelectron Spectroscopy (XPS) analyses. The in vitrobioactivity was studied by means of Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared Spectroscopy (FTIR) after soaking in simulated body fluid (SBF). Surface charge and isoelectric point were investigated by means of zeta potential measurements. Free radical scavenging activity evaluation was performed in order to investigate the antioxidant ability of glass samples. Finally, the functionalization selective killing activity towards osteosarcoma cells was in vitroassayed by the metabolic 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) test and compared with non-tumoral control bone cells. The presence of polyphenols on the surfaces was confirmed by XPS analyses by the appearance of characteristic peaks (C-O and C=O bonds) in the carbon and oxygen regions. The Folin&Ciocalteu test demonstrated the presence and activity of polyphenols on all the substrates and evidenced a clear relation between surface reactivity and grafting ability. The bioactivity tests showed the deposition of hydroxyapatite on the functionalized samples and an influence of biomolecules on its amount and shape for glasses. Zeta potential measurements evidenced a shift of the isoelectric point of glass samples after functionalization. A certain antioxidant activity of bare glass has been evidenced and it is improved by the grafting of tea polyphenols. Accordingly, MTT results confirmed polyphenols selective killer activity towards osteosarcoma cells whose viability was significantly decreased in comparison with safe bone cells. XPS analyses, zeta potential measurements and Folin&Ciocalteu tests showed the presence and the activity of the polyphenols on the surfaces. Bioactivity tests highlighted an improvement of the deposition of hydroxyapatite on the surface of the functionalized glass samples. Certain antioxidant ability has been evidenced for glass samples and was further improved by tea polyphenols. Moreover, a selective toxic activity towards tumor cells was in vitropreliminary confirmed. In conclusions polyphenols were successfully grafted to the surface of glass and Ti6Al4V samples maintaining their activity. Polyphenols improve in vitro bioactivity, antioxidant and anticancer ability of glass. The surface functionalization seems to be a good way to combine the properties of bioactive materials for bone contact applications with those of polyphenols

Osteogenesis is key to fracture healing and osteointegration of implanted material. Modification of surfaces on a nanoscale has been shown to affect cell interaction with the material and can lead to preferential osteogenesis. We hypothesised that osteogenesis could be induced in a heterogeneous population of osteoprogenitor cells by circular nanopits on a material surface. Furthermore, we intended to assess any correlation between nanopit depth and osteoinductive potential. The desired topographies were embossed onto polycaprolactone (PCL) discs using pre-fabricated nickel shims. All pits had a diameter of 30μm and investigated pit depths were 80nm, 220nm and 333nm. Scanning electron microscopy confirmed successful embossing and planar controls were shown to be flat. A bone marrow aspirate was obtained from the femoral neck of a healthy adult undergoing a hip replacement. After establishing a culture, cells were seeded onto the PCL discs, suspended in basal media and incubated. Samples were fixed and stained after three and 28 days. Cells were stained for the adhesion molecule vinculin after three days. Lowest concentrations of vinculin were seen in the planar control group. Osteoprogenitor cells on the shallowest pits, 80nm, had larger and brighter adhesion complexes. After 28 days, osteocalcin and osteopontin expression were used as markers of cell differentiation into an osteoblastic phenotype. 220nm deep pits consistently produced cells with the highest concentrations of osteopontin (p = 0.017) with a similar trend of osteocalcin expression. Cells on all topographies had higher expression levels than the planar controls. We demonstrated stimulation of osteogenesis in a heterogeneous population of osteoprogenitor cells. This cell mix is similar to that present in fracture healing and after reaming for intramedullary devices or uncemented implants. All nanopit depths gave promising results with an optimum depth of 220nm after 28 days

Introduction. The objective of this study was to identify fat emboli in the arterioles of the femoral bone marrow by Scanning Electron Microscopy (SEM) after glucocorticoid administration. Methods. Female adult rabbits weighing 3.5 to 4.0 kg received a single injection of prednisolone at a dose of 4 mg/kg body weight. The day after injection was designated as day 1. Control rabbits were injected with only physiological saline and euthanized on day 14. The femoral bone marrow was obtained on days 5, 8, and 14, and processed for SEM. Aortic blood serum was passed through a filter, and the filter was processed for SEM. Some SEM specimens were embedded in a plastic resin and sectioned for correspondence of SEM-photomicroscopy or SEM-TEM. Results. In the controls, small fat globules were present in sinusoids and venules, but were absent from the arterioles. On day 5, fat globules were found in the lumina of both sinusoids and arterioles. Complete arteriolar occlusion was not found. On day 8, fat globules were often encountered in the venous and arteriolar lumina. Some small arterioles were completely occluded by fat emboli. On day 14, fat globules were present in the arterioles and some small and large arterioles were completely occluded. Blood drawn from the aorta contained fat globules in both the controls and rabbits injected with prednisolone. Conclusion. A small amount of prednisolone induced the presence of fat globules in arterioles as early as day 5, complete occlusion of small arterioles on day 8, and occlusion of large arterioles on day 14. The source of fat globules and the mechanism of arteriolar occlusion were discussed

Summary. Properties of human amniotic membrane are particularly interesting. To use it as an Advanced Therapeutic Medicinal Product in bone surgery, we are evaluating its association with a potentially osteoinductive scaffold. Introduction. The human Amniotic Membrane (hAM) is known to have a good potential to help the regeneration of tissues. It has been used for 100 years in many medical disciplines because of its properties: a membrane containing stem cells and growth factors, with low immunogenicity and anti-microbial, anti-inflammatory, anti-fibrotic and analgesic properties. Moreover, previous published data showed the possibility of in vitro osteodifferenciation of the whole tissue. We aim to use hAM as an Advanced Therapeutic Medicinal Product for bone repair to treat large defects or pseudarthrosis. So we are studying the association of hAM with nanofiber jet sprayed polycaprolactone (PCL) scaffolds and the possibility to induce its osteodifferenciation. Materials and Methods. HAM from cesarean delivery were provided by a local bank of tissue. A biodegradable microfiber PCL scaffold (∼500 μm thick) was produced using a novel jet spraying technique and provided by Biomedical Tissues society (Nantes, France). We cultured hAM in contact with PCL scaffolds either in MSCs expansion medium or in MSCs osteogenic medium. Then we grafted these montages in an ectopic murin model (in subcutaneous implantation) and we explanted grafted tissues after 1, 2, 4 and 8 weeks. Osteogenic potential was evaluated by immunological studies immediately after in vitro cell studies and after explantations from the mice. Control studies were performed with human mesenchymal stromal cells (hMSCs) seeded on PCL scaffold in MSCs osteogenic medium and cultured with/ without dynamic culture, via an orbital rotator at 150 rpm for 28 days. Cell viability, proliferation and osteoblastic differentiation were evaluated at different times of culture until 28 days. Results. To date, in vitro studies showed a macroscopic mineralization of hAM cultured in MSCs osteogenic medium. Osteogenic potential evaluated by immunological investigations are currently underway. Control studies showed that:. - PCL jet sprayed scaffolds supported proliferation and maintained viability of hMSCs. - Scanning electron microscopy analysis and confocal imaging showed cell attachment with a spread cell morphology after just 1.5 hours. Cells attached along the PCL nanofibres.?. - Entire scaffold depth was infiltrated with cells at days 7 and 28, as seen by DAPI and hematoxylin and eosin staining. - Minimal collagen deposition was evident after 7 days but was observed in significant amounts after 28 days. Static conditions had the greatest collagen matrix production. - Alkaline phosphatse gene expression increased in dynamic conditions compared to 2D cultures. Osteocalcin gene expression increased on PCL scaffolds compared to 2D plastic. - Dynamic loading did not appear necessary for proliferation, infiltration or collagen production. Discussion. The association of the hAM with an osteoinductive scaffold could have 2 benefits:. - The handling of the hAM. - The osteodifferentiation of the hAM without the employment of chemical products (osteoinductive supplements that would need to be use with a “good manufacturing products” validation). These preliminary data showed that PCL scaffolds presented osteoinduction properties. The association of hAM with PCL scaffolds seems to be a good compromise answering both our needs

Objectives

The Attune total knee arthroplasty (TKA) has been used in over 600 000 patients worldwide. Registry data show good clinical outcome; however, concerns over the cement-tibial interface have been reported. We used retrieval analysis to give further insight into this controversial topic.

Conventional amputation prostheses rely on the attachment of the socket to the stump, which may lead to soft-tissue complications. Intraosseous transcutaneous amputation prostheses (ITAPs) allow direct loading of the skeleton, but their success is limited by infection resulting from breaching of the skin at the interface with the implant. Keratinocytes provide the skin’s primary barrier function, while hemidesmosomes mediate their attachment to natural ITAP analogues. Keratinocytes must attach directly to the surface of the implant. We have assessed the proliferation, morphology and attachment of keratinocytes to four titaniumalloy surfaces in order to determine the optimal topography in vitro. We used immunolocalisation of adhesion complex components, scanning electron microscopy and transmission electron microscopy to assess cell parameters.

We have shown that the proliferation, morphology and attachment of keratinocytes are affected by the surface topography of the biomaterials used to support their growth. Smoother surfaces improved adhesion. We postulate that a smooth topography at the point of epithelium-ITAP contact could increase attachment in vivo, producing an effective barrier of infection.

Ovine articular chondrocytes were isolated from cartilage biopsy and culture expanded in vitro. Approximately 30 million cells per ml of cultured chondrocytes were incorporated with autologous plasma-derived fibrin to form a three-dimensional construct. Full-thickness punch hole defects were created in the lateral and medial femoral condyles. The defects were implanted with either an autologous ‘chondrocyte-fibrin’ construct (ACFC), autologous chondrocytes (ACI) or fibrin blanks (AF) as controls. Animals were killed after 12 weeks. The gross appearance of the treated defects was inspected and photographed. The repaired tissues were studied histologically and by scanning electron microscopy analysis.

All defects were assessed using the International Cartilage Repair Society (ICRS) classification. Those treated with ACFC, ACI and AF exhibited median scores which correspond to a nearly-normal appearance. On the basis of the modified O’Driscoll histological scoring scale, ACFC implantation significantly enhanced cartilage repair compared to ACI and AF. Using scanning electron microscopy, ACFC and ACI showed characteristic organisation of chondrocytes and matrices, which were relatively similar to the surrounding adjacent cartilage.

Implantation of ACFC resulted in superior hyaline-like cartilage regeneration when compared with ACI. If this result is applicable to humans, a better outcome would be obtained than by using conventional ACI.

Objectives

We have observed clinical cases where bone is formed in the overlaying muscle covering surgically created bone defects treated with a hydroxyapatite/calcium sulphate biomaterial. Our objective was to investigate the osteoinductive potential of the biomaterial and to determine if growth factors secreted from local bone cells induce osteoblastic differentiation of muscle cells.

Objectives

There is increasing application of bone morphogenetic proteins (BMPs) owing to their role in promoting fracture healing and bone fusion. However, an optimal delivery system has yet to be identified. The aims of this study were to synthesise bioactive BMP-2, combine it with a novel α-tricalcium phosphate/poly(D,L-lactide-co-glycolide) (α-TCP/PLGA) nanocomposite and study its release from the composite.

Ciprofloxacin hydrochloride-loaded microspheres were prepared by a spray-drying method using pectin and chitosan. The effects of different polymers and drug ratios were investigated.

The most appropriate carriers were selected by in vitro testing. A rat methicillin-resistant Staphylococcus aureus osteomyelitis model was used to evaluate the effects of the loaded microspheres.

The drug was released rapidly from the pectin carrier but this was more sustained in the chitosan formulation.

Chitosan microspheres loaded with ciprofloxacin hydrochloride were more effective for the treatment of osteomyelitis than equivalent intramuscular antibiotics.

An experimental sheep model was used for impaction allografting of 12 hemiarthroplasty femoral components placed into two equal-sized groups. In group 1, a 50:50 mixture of ApaPore hydroxyapatite bone-graft substitute and allograft was used. In group 2, ApaPore and allograft were mixed in a 90:10 ratio. Both groups were killed at six months. Ground reaction force results demonstrated no significant differences (p > 0.05) between the two groups at 8, 16 and 24 weeks post-operatively, and all animals remained active. The mean bone turnover rates were significantly greater in group 1, at 0.00206 mm/day, compared to group 2 at 0.0013 mm/day (p < 0.05). The results for the area of new bone formation demonstrated no significant differences (p > 0.05) between the two groups. No significant differences were found between the two groups in thickness of the cement mantle (p > 0.05) and percentage ApaPore-bone contact (p > 0.05).

The results of this animal study demonstrated that a mixture of ApaPore allograft in a 90:10 ratio was comparable to using a 50:50 mixture.