The purpose of this study was to evaluate A total of 60 Sprague-Dawley rats (125 g to 149 g) were implanted
subcutaneously with SWCNT/PLAGA composites (10 mg SWCNT and 1gm
PLAGA 12 mm diameter two-dimensional disks), and at two, four, eight
and 12 weeks post-implantation were compared with control (Sham)
and PLAGA (five rats per group/point in time). Rats were observed
for signs of morbidity, overt toxicity, weight gain and food consumption,
while haematology, urinalysis and histopathology were completed
when the animals were killed.Objectives
Methods
Direct metal printed (DMP) porous iron implants possess promising mechanical and corrosion properties for various clinical application. Nevertheless, there is a requirement for better co-relation between in vitro and in vivo corrosion and biocompatibility behaviour of such biomaterials. Our present study evaluates absorption of porous iron implants under both static and dynamic conditions. Furthermore, this study characterizes their cytocompatibility using fibroblastic, osteogenic, endothelial and macrophagic cell types. In vitro degradation was performed statically and dynamically in a custom-built set-up placed under cell culture conditions (37 °C, 5% CO2 and 20% O2) for 28 days. The morphology and composition of the degradation products were analysed by scanning electron microscopy (SEM, JSM-IT100, JEOL). Iron implants before and after immersion were imaged by μCT (Quantum FX, Perkin Elmer, USA).
Biodegradable metals as orthopaedic implant materials receive substantial scientific and clinical interest. Marketed cardiovascular products confirm good biocompatibility of iron. Solid iron biodegrades slowly in vivo and has got supra-physiological mechanical properties as compared to bone and porous implants can be optimized for specific orthopaedic applications. We used Direct Metal Printing (DMP)3 to additively manufacture (AM) scaffolds of pure iron with fine-tuned bone-mimetic mechanical properties and improved degradation behavior to characterize their biocompatibility under static and dynamic 3D culture conditions using a spectrum of different cell types. Atomized iron powder was used to manufacture scaffolds with a repetitive diamond unit cell design on a ProX DMP 320 (Layerwise/3D Systems, Belgium). Mechanical characterization (Instron machine with a 10kN load cell, ISO 13314: 2011), degradation behavior under static and dynamic conditions (37ºC, 5% CO2 and 20% O2) for up of 28 days, with μCT as well as SEM/energy-dispersive X-ray spectroscopy (EDS) (SEM, JSM-IT100, JEOL) monitoring under in vivo-like conditions.
Summary Statement. A novel biomimetic polydioxanone tendon patch with woven and electrospun components is biocompatible, recapitulates native tendon architecture and creates a tissue-healing microenvironment directed by a subpopulation of regenerative macrophages. The woven component provides tensile strength while the tendon heals. Introduction. There is great interest in the use of biomimetic devices to augment tendon repairs. Ideally, implants improve healing without causing adverse local or systemic reactions.
Introduction. Currently, different techniques to evaluate biocompatibility of orthopaedic materials, including two-dimensional (2D) cell culture for metal and ceramic wear debris and floating 2D surfaces or three-dimensional (3D) agarose gels for UHMWPE wear debris, are used. We have developed a single method using 3D agarose gels that is suitable to test the biocompatibility of all three types of wear debris simultaneously. Moreover, stimulation of the cells by wear particles embedded in a 3D gel better mimics the in vivo environment. Materials and Methods. Clinically relevant sterile UHMWPE and CoCr wear particles were generated using methodologies described previously [1,2]. Commercially available nanoscale and micron-sized silicon nitride (Si. 3. N. 4. ) particles (<50 nm and <1 μm, Sigma UK) were sterilised by heat treatment for 4h at 180°C. Agarose-particle suspensions were prepared by mixing warm 2% (w/v) low-melting-point agarose solution with the particles dispersed by sonication in DMEM culture media. The suspensions were then allowed to set at room temperature for 10 min in 96 well culture plates. Sub-confluent L929 murine fibroblasts were cultured on the prepared gels for up to 6 days in 5% (v/v) CO. 2. at 37°C. After incubation, the viability of cells was measured using the ATP-lite assay. The results were expressed as mean ± 95% confidence limits and the data was analysed using one-way ANOVA and Tukey-Kramer post-hoc analysis. Results and Discussion. The gels were observed to ensure uniform distribution of particles and migration of cells into the gel. No significant reduction in viability was observed for nanoscale and micron-sized Si. 3. N. 4. particles at low doses (0.5 μm. 3. per cell) and high doses (50 μm. 3. per cell), or for UHMWPE wear debris at high doses (100 μm. 3. per cell) [Figure1]. Moreover, the viability was significantly reduced for high doses of CoCr wear debris (50 μm. 3. per cell) and the positive control, camptothecin (2 μg.ml. −1. ) at day 6 [Figure1]. These results are consistent with the literature [2,3] and therefore validate our 3D agarose cell culture method for comparing cytotoxicity of polymer, metal and ceramic particles in a single assay, simultaneously. Conclusion.
Summary Statement. Innovative nanocomposite carbon coating doped with Si can significantly improve the osseintegration of orthopaedics implants. Additionally, this kind of coating increases the mechanical resistance of the implants, what is especially important on case of joints (frictional pairs). Introduction. Use of layers of carbon-doped silicon, which leads to the synthesis of layers improving mechanical and biological characteristics, let obtain good strength by volume features. Suitable introduction to the structure of amorphous silicon dioxide layer allow for the production of higher adhesion to metallic substrates and consequently the increased thickness and hardness. The increased thickness of the layer leads to a stronger diffusion barrier to harmful metal ions from the implant material and thus consequently improving the biocompatibility of the implant. Moreover, a silicon beneficial effect on stress relaxation layer formed during the synthesis. This allows for improved biocompatibility, also affects other property obtained in the case of silicon carbide layers, the bacteriastability. This further protects the surface of the implant against the risk of bacterial colonization in both the implantation and subsequent use in the body, and preferably suppressing inflammation and faster healing of surgical wounds. The thus obtained product is much better than the biological and mechanical parameters of currently offered. Patients & Methods. In order to evaluate the fabricated coatings conditions examination of the basic physicochemical and mechanical properties were conducted (AFM, Raman, XPS, nanoindentation technique). The in vitro and in vivo tests were also conducted. As a biological material osteoblast Saos-2 cells and endothelial cells line EA. 926 were used. For the evaluation of proliferation and cytotoxicity a “live/dead” test was used. For testing bactericidal activity of the C/Si coatings, an exponential growth phase of E. coli strain DH5 α was used. Test of bacterial immediate toxicity and bacterial colonization were performed. A model of rabbits and guinea pigs were used to obtained results with reference to irritation, intradermal reactivity, sensitization, local effects after implantation with the histopathological examination, cytotoxicity test. Results. XPS results have shown that the silicon content for each group of samples, both steel and titanium alloy is about 3, 4 and 5 percent. Increasing the concentration of silicon above 5% results in the weakening of the mechanical properties of the layer and lead to delamination of the sterilization process. Addition of silicon in the range of 3–5% does not negatively affect the mechanical and structural properties of the modified surface and from this point of view, all the criterion of strength. Performed studies confirmed very good mechanical properties of C/Si coatings. In vitro studies have indicated the optimal concentration of silicon in the coating, where the material is biocompatible and also has good antibacterial properties.
Stryde® lengthening nail has been recently withdrawn because of concerns about osteolysis and other bone lesions that have been observed early after implantation. The present study analyses the incidence and features of these bone lesions in our patients. This is a retrospective review of a series of patients from two centres specializing in limb reconstruction. Inclusion criteria was a history of surgery with Stryde® lengthening nail with more than one year follow-up available. All postoperative x-rays were and clinical notes were reviewed.Introduction
Materials and Methods
The utilization of silver as an anti-infective agent is a subject of debate within the scientific community, with recurring discussions surrounding its biocompatibility. Presently, galvanic silver coating finds widespread clinical application in mitigating infection risks associated with large joint arthroplasties. While some instances have linked this coating to sporadic cases of localized argyria, these occurrences have not exhibited systematic or functional limitations. To address concerns regarding biocompatibility, a novel approach has been devised for anti-infective implant coatings: encapsulating silver nitrate within a biopolymer reservoir for non-articulating surfaces. This poly-L-lactic acid layer releases silver ions gradually, thereby circumventing biocompatibility concerns. Female C57BL/6 mice were utilized as an experimental model, with 6x2 mm Ti6Al4V discs, coated with or without the biopolymer-protected silver coating, implanted subcutaneously on both sides of the vertebrae. Daily blood samples were collected, and serum was analyzed for C-reactive protein (CRP) and silver concentration. After three days, histopathological analyses were conducted on the surrounding soft tissue pouch.Aim
Method
Bone fractures are highly observed clinical situation in orthopaedic treatments. In some cases, there might be non-union problems. Therefore, recent studies have focused on tissue engineering applications as alternative methods to replace surgical procedures. Various biopolymer based scaffolds are produced using different fabrication techniques for bone tissue engineering applications. In this study, hydroxyapatite (HAp) and loofah containing carboxymethyl chitosan (CMC) scaffolds were prepared. In this regard, first 4 ml of CMC solution, 0.02 g of hydroxyapatite (HAP) and 0.06 g of poly (ethylene glycol) diglycidyl ether (PEGDE) were mixed in an ultrasonic bath until the HAp powders were suspended. Next, 0.04 g of loofah was added to the suspension and with the help of PEGDE as the cross-linking agent, then, the mixture was allowed to cross-link at 40oC overnight. Finally, the three-dimensional, porous and sponge-like scaffolds were obtained after lyophilization (TELSTAR - LyoQuest −85) at 0.1 mbar and −25°C for 2 days. Morphologies, chemical structures and thermal properties of the scaffolds were characterized by scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and thermogravimetric differential thermal analysis (TGA/DTA), respectively. In addition, swelling behavior and mechanical properties of the scaffolds under compression loading were determined. In order to investigate biocompatibility of the scaffolds, WST-1 colorimetric assay at days 0, 1, 3, 5 and 7 was conducted by using human dermal fibroblast. Also, histological and morphological analysis were performed for cell attachment at day 7. In conclusion, the produced scaffolds showed no cytotoxic effect. Therefore, they can be considered as a candidate scaffold for bone tissue regeneration. Further studies will be performed by using bone marrow and periosteum derived mesenchymal stem cells with these scaffolds.
Additive manufacturing has led to numerous innovations in orthopaedic surgery: surgical guides; surface coatings/textures; and custom implants. Most contemporary implants are made from titanium alloy (Ti-6Al-4V). Despite being widely available industrially and clinically, there is little published information on the performance of this 3D printed material for orthopaedic devices with respect to regulatory approval. The aim of this study was to document the mechanical, chemical and biological properties of selective laser sintering (SLS) manufactured specimens following medical device (TOKA®, 3D Metal Printing LTD, UK) submission and review by the UK Medicines and Healthcare Products Regulatory Agency (MHRA). All specimens were additively manufactured in Ti-6Al-4V ELI (Renishaw plc, UK). Mechanical tests were performed according to ISO6892-1, ISO9585 and ISO12107 for tensile (n=10), bending (n=3) and fatigue (n=16) respectively (University of Bath, UK). Appropriate chemical characterisation and biological tests were selected according to recommendations in ISO10993 and conducted by external laboratories (Wickham Labs, UK; Lucideon, UK; Edwards Analytical, UK) in adherence with Good Lab Practise guidelines. A toxicological review was conducted on the findings (Bibra, UK).Abstract
Objectives
Methods
Because of its high strength and allowance for bone integration, Ti-6Al-4V is the most commonly used material for load bearing bone implants. Compared to conventional production methods, 3D printing Ti-6Al-4V introduces advantages as (near-) net-shape manufacturing of complex geometries, and optimization of utilization rate of the material. However, as result of the additively production procedure, microstructure and surface properties differ from those manufactured using conventional techniques. Therefore, the resulting mechanical properties and biocompatibility of the 3D printed Ti-6Al-4V are investigated in this study. First, it was aimed to reveal the tensile properties of the material and verify if these depend on build orientation. Second, it was determined which post process method provides the best osteoconductivity. Tensile specimens were designed and 3D printed using Selective Laser Melting (SLM) technique. Subsequently, specimens were heat treated and tensile properties were determined as described in ASTM E 8M-04. Cell culture discs were manufactured using the same production method. The influence of two different surface treatments (sand-blasting versus polishing) on osteoconductivity was analysed by a 30 day Introduction
Materials and methods
Since 2010, there has been a sharp decline in the use of metal-on-metal joint replacement devices due to adverse responses associated with the release of metal wear particles and ions in patients. Surface engineered coatings offer an innovative solution to this problem by covering metal implant surfaces with biocompatible and wear resistant materials. The present study tests the hypothesis whether surface engineered coatings can reduce the overall biological impact of a device by investigating recently introduced silicon nitride coatings for joint replacements. Biological responses of peripheral blood mononuclear cells (PBMNCs) to Si3N4 model particles, SiNx coating wear particles and CoCr wear particles were evaluated by testing cytotoxicity, inflammatory cytokine release, oxidative stress and genotoxicity. Clinically relevant wear particles were generated from SiNx-on-SiNx and CoCr-on-CoCr bearing combinations using a multidirectional pin-on-plate tribometer. All particles were heat treated at 180°C for 4 h to destroy endotoxin contamination. Whole peripheral blood was collected from healthy donors (ethics approval BIOSCI 10–108, University of Leeds). The PBMNCs were isolated using Lymphoprep (Stemcell) and incubated with particles at various volumetric concentrations (0.5 to 100 µm3 particles/cell) for 24 h in 5% (v/v) CO2 at 37°C. After incubation, cell viability was measured using the ATPlite assay (Perkin Elmer); TNF-alpha release was measured by ELISA (Invitrogen); oxidative stress was measured using H2DCFDA (Abcam); and DNA damage was measured by comet assay (Tevigen). The results were expressed as mean ± 95% confidence limits and the data was analysed using one-way ANOVA and Tukey-Kramer post-hoc analysis. No evidence of cytotoxicity, oxidative stress, TNF-alpha release, or DNA damage was observed for the silicon nitride particles at any of the doses. However, CoCr wear particles caused cytotoxicity, oxidative stress, TNF-alpha release and DNA damage in PBMNCs at high doses (50 µm3 particles per cell). This study has demonstrated the in-vitro biocompatibility of SiNx coatings with primary human monocytic cells. Therefore, surface engineered coatings have potential to significantly reduce the biological impact of metal components in future orthopaedic devices.
We have previously demonstrated that peroxide crosslinked vitamin E-blended UHMWPE maintains its clinically-required wear and mechanical properties [1]. This material can potentially be used as an irradiation-free bearing surface for TJA. However, using organic peroxides in medical devices requires a thorough examination of tissues in contact with the implant. For this study we crosslinked polyethylene using five times the needed concentration of peroxide (2,5-Dimethyl-2,5-di(t-butylperoxy)-hexyne-3 or P130), followed by implantation to determine implant biocompatibility, and pre and post implant peroxide residual contents. The study was performed after institutional approval following ISO standard 10993–6. Study groups: not crosslinked (0.2 (1050) VE), crosslinked (0.2 VE (1050)/5% P130) and crosslinked-high temperature melted (HTM) (0.2 VE (1050)/5% P130). Materials were blended and consolidated, machined (2.5 diameter × 2.5 cm height), sterilized and implanted in the dorsum New Zealand white rabbits. Pre and post implantation FTIR was performed. Two samples were implanted in each rabbit; Introduction
Methods
We implanted nails made of titanium (Ti6Al4V) and of two types of glass ceramic material (RKKP and AP40) into healthy and osteopenic rats. After two months, a histomorphometric analysis was performed and the affinity index calculated. In addition, osteoblasts from normal and osteopenic bone were cultured and the biomaterials were evaluated in vitro. In normal bone the rate of osseointegration was similar for all materials tested (p >
0.5) while in osteopenic bone AP40 did not osseointegrate (p >
0.0005). In vitro, no differences were observed for all biomaterials when cultured in normal bone-derived cells whereas in osteopenic-bone-derived cells there was a significant difference in some of the tested parameters when using AP40. Our findings suggest that osteopenic models may be used in vivo in the preclinical evaluation of orthopaedic biomaterials. We suggest that primary cell cultures from pathological models could be used as an experimental model in vitro.
The osseointegration of implants is related to the early interactions between osteoblastic cells and titanium surfaces. The behavior of osteoblast cells was compared on four different titanium surfaces in vitro and in vivo: machined, blasted, plasma spray and micro-arc oxidation. X-ray diffraction and scanning electron microscope investigations were performed in order to assess the structure and morphology. Biologic and morphologic responses to the osteoblast cell lines (Saos-2) were then examined, using Promega proliferation assay, alkaline phosphatase activity, vβ3 integrin expression and cytoskeleton staining (Rhodamine-Phallodine). The analysis of gene expression for osteocalcin and collagen I was done through RT-PCR. In addition, differential histologic evaluation and interfacial strength at the bone-implant interfaces were then evaluated in the distal femur of four beagle dogs. In conclusion, micro-arc oxidation of titanium appears to exhibit more favorable osteoblast adhesion and stronger interfacial strength than the compared groups in vitro and in vivo as well.
The steric and electrostatic complementarity of natural proteins and other macromolecules are a result of evolutionary processes. The role of such complementarity is well established in protein-protein interactions, accounting for the known protein complexes. To our knowledge, non-biological systems have not been a part of such evolutionary processes. Therefore, it is desirable to design and develop nonbiological surfaces, such as implant devices (e.g. bone growth for non-cemented fixation), that exhibit such complementarity effects with the natural proteins. Cell attachment and spreading in vitro is generally mediated by adhesive proteins such as fibronectin and vitronectin [ The role of surface characteristics, such as topography, has been studied in recent years without the emergence of a comprehensive and consistent model [ We designed and produced ceramic [
Silver is known for its excellent antimicrobial activity, including activity against multiresistant strains. The aim of the current study was to analyze the biocompatibility and potential influence on the fracture healing process a silver-coating technology for locking plates compared to silver-free locking plates in a rabbit model. The implants used in this study were 7-hole titanium locking plates, and plasma electrolytic oxidation (PEO) silver coated equivalents. A total of 24 rabbits were used in this study (12 coated, 12 non-coated). An osteotomy of the midshaft of the humerus was created with an oscillating saw and the humerus stabilized with the 7 hole locking plates with a total of 6 screws. X-rays were taken on day 0, week 2, 4, 6, 8, and 10 for continuous radiographical evaluation of the fracture healing. All animals were euthanized after 10 weeks and further assessment was performed using X-rays, micro-CT, non-destructive four-point bending biomechanical testing and histology. Furthermore, silver concentration was measured in the kidney, liver, spleen and brain.Aim
Methods
Silicon nitride (SiN) is a recently introduced bearing material for THR that has shown potential in its bulk form and as a coating material on cobalt-chromium (CoCr) substrates. Previous studies have shown that SiN has low friction characteristics, low wear rates and high mechanical strength. Moreover, it has been shown to have osseointegration properties. However, there is limited evidence to support its biocompatibility as an implant material. The aim of this study was to investigate the responses of peripheral blood mononuclear cells (PBMNCs) isolated from healthy human volunteers and U937 human histiocytes (U937s) to SiN nanoparticles and CoCr wear particles. SiN nanopowder (<50nm, Sigma UK) and CoCr wear particles (nanoscale, generated in a multidirectional pin-on-plate reciprocator) were heat-treated for 4 h at 180°C and dispersed by sonication for 10 min prior to their use in cell culture experiments. Whole peripheral blood was collected from healthy donors (ethics approval BIOSCI 10–108, University of Leeds). The PBMNCs were isolated using Lymphoprep® as a density gradient medium and incubated for 24 h in 5% (v/v) CO2at 37°C to allow attachment of mononuclear phagocytes. SiN and CoCr particles were then added to the phagocytes at a volume concentration of 50 µm3 particles per cell and cultured for 24 h in RPMI-1640 culture medium in 5% (v/v) CO2 at 37°C. Cells alone were used as a negative control and lipopolysaccharide (LPS; 200ng/ml) was used as a positive control. Cell viability was measured after 24 h by ATPLite assay and tumour necrosis factor alpha (TNF-α) release was measured by sandwich ELISA. U937s were co-cultured with SiN and CoCr particles at doses of 0.05, 0.5, 5 and 50 µm3 particles per cell for 24h in 5% (v/v) CO2 at 37 C. Cells alone were used as a negative control and camptothecin (2 µg/ml) was used as a positive control. Cell viability was measured after 0, 1, 3, 6 and 9 days. Results from cell viability assays and TNF-α response were expressed as mean ±95% confidence limits and the data was analysed using one-way ANOVA and Tukey-Kramer post-hoc analysis.Introduction
Methods