Papers by Keyword: Biocompatibility

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Authors: Anke Bernstein, Renate Gildenhaar, Georg Berger, Hermann O. Mayr
Abstract: Bioactive ceramics such as β-tricalcium phosphate (β-TCP) promote and enhance biological fixation. Ceramics with a porous interconnected structure are suited for facilitation of bony ingrowth. An interconnected pore system with pore diameters in excess of 100 µm is required for cell penetration, tissue ingrowth, vascularization and nutrient delivery to the centre of the regenerating tissue. Human osteoblasts were cultured on the surface of a ceramic. In an in-vivo study, β-TCP samples with a porous interconnected structure were implanted into the femur of sheep and then investigated 6 weeks after operation. Histological analysis was performed on the area surrounding the implant. An indentation test was performed to complete failure of the bone/ceramic compound. Linear load, peak load and stiffness were recorded. All cylinders were found to be biocompatible and osteoconductive. Bone was more abundant in the outer ring than in the rest of the cylinder. The ceramic/bone compound was of low mechanical grade.
Authors: Ho Yeon Song, Young Hee Kim, Jyoti M. Anirban, In Seon Byun, Kyung A Kwak, Byong Taek Lee
Abstract: Calcium phosphate ceramics such as hydroxy apatite (HA), β-tricalcium phosphate (β-TCP) and bicalcium phosphate (BCP) have been used as a bone graft biomaterial because of their good biocompatibility and similarity of chemical composition to natural bones. To increase the mechanical and osteoconductive properties, the granules and spongy type porous bone graft substitutes were prepared by fibrous monolithic process and polyurethane foam replica methods, respectively. The pore sizes obtained using these approaches ranged between 100-600 µm. The cytotoxicity, cellular proliferation, differentiation and ECM deposition on the bone graft substitutes were observed by SEM and confocal microscopy. Moreover, the scaffolds were implanted in the rabbit femur. New bone formation and biodegradation of bone graft were observed through follow-up X-ray, micro-CT analysis and histological findings. After several months (2, 3, 6, 12 and 24 months) of implantation, new bone formation and ingrowths were observed in defect sites of the animal by CaP ceramics and 2 to 3 times higher bone ingrowths were confirmed than that of the normal trabecular bones in terms of total bone volume (BV).
Authors: Sha Luo, Qing Qing Zhang, Yan Chang Zhang, Chao Li, Xiao Qing Xu, Tie Tao Zhou
Abstract: Magnesium alloys have a good application prospect in the fields of bone implants and cardiovascular stents due to their excellent properties, such as close density and elastic modulus to those of nature bone, high specific strength and rigidity, biodegradation and biocompatibility. In this paper, the feasibility of the use of the forged Mg-Li-X alloys (Mg-Li-Al-Zn-Ca-Sr) as biodegradable metals was investigated by immersion tests in the Hanks solution and skin-tissue implantation tests. The methods of SEM-EDS and XRD were used to research the corrosion morphology and corrosion products of the forged Mg-Li-X alloys after the in-vitro and in-vivo tests. At last, the in-vitro cytotoxicity was investigated by the MTT tests on L929 cells. Results showed that corrosion mechanism of the forged Mg-Li alloys was pitting and the surfaces were covered by Mg (OH)2,CaCO3 and Ca (H2PO4)2 . During the 5 weeks implantation period, the rats survived from the operation, which indicates that the elements and the compounds formed are non-toxic to the rats. The forged Mg-Li alloy showed Grade 0~1 cytotoxicity, which manifests the forged Mg-Li alloy has good biocompatibility and eligible toxicity for implant applications.
Authors: Xiao Jie Lian, Xu Mei Wang, Fu Zhai Cui
Abstract: In the present study, a new antibacterial bone graft substitute has been developed for repairing bone defects and inhibiting related infections at the same time. Calcium sulphate hemihydrate (CSH) was introduced into nanohydroxyapatite/collagen (nHAC) to prepare a self-setting in situ bone repair materials. The nHAC/CSH was used as a carrier of vancomycin (VCM) for anti-infection and the treatment of osteomyelitis. The VCM/nHAC/CSH composite was a porous scaffold with porosity of 38.8% and the compressive mechanical strength was about 4.8 MPa. The final setting time was about 15~20 min. The inhibition ratio of VCM/nHAC/CSH was more than 99.8% and the distinct inhibition zone of 18 mm was formed in Staphylococcus aureus bacterium incubation dish with VCM/nHAC/CSH disc in the center of agar matrix for 16 hours of incubation. After incubating 17 days at 37 in vitro, the concentration of vancomycin in elution fluild was around 12 μg/mL. Therefore, the VCM/nHAC/CSH bone substitute presents ideal self-setting antibacterial, cytocompatibility, sustained release properties and has great potential applications for the treatment of bone defect-related infection in orthopedic surgeries.
Authors: W. Han, Yue Dan Wang, Y.F. Zheng
Abstract: Nano TiO2 material is an extensively used and adequately studied material and has a close contact with human in various fields, such as dope, dye, ceramic, cosmetic and medicine. Therefore, it’s very important to study the biocompatibility and biosafety of nano TiO2 materials. In the present study, various nano TiO2 materials with different dimension and crystal structures were confected to suspensions with varied concentrations and evaluated in cell model (mouse fibrocyte) after autoclaving sterilization. After 24h, 48h and 72h of cell culture experiments, MTT assay was used to examine the cell proliferation behavior and the flow cytometry was used to examine the cell apoptosis behavior. The present results of cell experiment showed that nano TiO2 materials had no effect on cell proliferation and apoptosis in a certain range of time and concentration. MTT assay indicated the relative cell proliferation rate in all nano TiO2 material groups were above 92% and the toxicity grade were 0 or 1 class.
Authors: Paul Rosemann, Susanne Bender, Andreas Heyn, Jürgen Schmidt
Abstract: As bio-absorbable implant material the magnesium alloy Mg-1Ca is able to degrade in-vivo. The mechanical properties of this alloy are similar to those of human bone; both Mg and Ca are essential elements in human body. The main problem is the high corrosion rate of this alloy. Two coating systems based on plasma-chemical oxidation and an organic dip coating are applied onto MgCa1.0 magnesium alloy in order to slow down the corrosion rate. The corrosion behaviour of the coated alloys was investigated with electrochemical noise measurements. The influence of hydrogen evolution and increasing pH-value on the cytotoxicity was examined. The results of these investigations suggest that a combination of both coating systems leads to promising degradation properties.
Authors: Yun Cang Li, Cynthia Wong, Jian Yu Xiong, Peter D. Hodgson, Cui E Wen
Abstract: Interest in using titanium (Ti) alloys as load-bearing implant materials has increased due to their high strength to weight ratio, lower elastic modulus, and superior biocompatibility and enhanced corrosion resistance compared to conventional metals such as stainless steel and Co-Cr alloys. In the present study, the in vitro cytotoxicity of five binary titanium alloys, Ti15Ta, Ti15Nb, Ti15Zr, Ti15Sn and Ti15Mo, was assessed using human osteosarcoma cell line, SaOS-2 cells. The Cell proliferation and viability were determined, and cell adhesion and morphology on the surfaces of the binary Ti alloys after cell culture were observed by SEM. Results indicated that the Ti binary alloys of Ti15Ta, Ti15Nb and Ti15Zr exhibited the same level of excellent biocompatibility; Ti15Sn alloy exhibited a moderate biocompatibility while Ti15Mo alloy exhibited a moderate cytotoxicity. The SaOS-2 osteoblast-like cells had flattened and spread across the surfaces of the Ti15Ta, Ti15Nb, Ti15Zr and Ti15Sn groups; however, the cell shapes on the Ti15Mo alloy was shrinking and unhealthy. These results indicated that the Mo contents should be limited to a certain level in the design and development of new Ti alloys for implant material applications.
Authors: Luis Jesús Villarreal-Gómez, Ricardo Vera-Graziano, Maria Raquel Vega-Rios, Jose Luis Pineda-Camacho, Paris Astrid Mier-Maldonado, Horacio Almanza-Reyes, Jose Manuel Cornejo Bravo
Abstract: It is important to develop scaffolds that resemble the extracellular matrix, thereby facilitating tissue regeneration. The objective of this work is to evaluate the biocompatibility of scaffolds of poly (L-lactide) with pure and grafted hydroxyapatite, at various concentrations of reinforcement, in Wistar Rat tissues, to evaluate the potential application on hard tissue regeneration. The biocompatibility tests were carried out in vivo in Wistar rats by implanting the material into the subcutaneous tissue and muscle from 1 to 14 weeks and evaluating the surrounding tissue stained with hematoxylin-eosin. All variants of scaffolds provoked an inflammatory response from mild to moderate, without showing necrosis. These results show that even if there is recognition of the implanted materials by the immune system, it does not provoke a violent response that damages the surrounding tissue, implying that the materials to be implanted for use in hard tissue can cause a mild reaction and tolerable long term effect that does not prevent their later use in hard tissue regeneration.
Authors: Wei Han, Yue Dan Wang, Yu Feng Zheng
Abstract: TiO2 nanomaterials with different dimensions(zero and one), sizes(20nm, 50nm and 100nm in diameter) and crystal structures(100% rutile, 100% anatase and combination of 20% rutile and 80% anatase) were confected to suspensions and ointment with varied concentrations and evaluated in animal model (Balb-c mouse). These mouse were divided into various groups randomly, with suspension intraperitoneally injected or ointment transdermally daubed. Heart, lung, liver and kidney were collected and prepared to HE sample after one week. Spectrophotometry was applied to study total antioxide capability and catalase activity of blood and tissues. It has been shown that all TiO2 nanomaterial groups had no effect on lives’ morphology and oxidative stress, with no obvious histopathological changes observed in heart, lung, liver and kidney, and these tissues presented no vacuolar degeneration, necrosis edema, engorgement and inflammation.
Authors: Sybele Saska, N.S. Nunes, Emelly Aveiro, Cristina A.C. Pavan, S.H. Santagneli, J.A.D.B. Campos, Ana Maria M. Gaspar, Sidney José Lima Ribeiro, Younes Messaddeq
Abstract: Bioceramics with different Ca/P ratio were prepared from a mechanical mixture of NaPO3, CaCO3, Ca(OH)2 and phosphate buffer solution and implanted in rats subcutaneous tissues. The cements were characterized by Thermogravimetric analysis (TG-TDA), X-ray diffraction and 31P-NMR. The implant sites were excised after 1, 4 and 16 weeks, fixed, dehydrated, included in paraffin wax for serial cutting and examined under the light transmitted microscope. They were biocompatible and biodegradable when implanted in rat subcutaneous. None of the materials induced ectopic osteogenesis. According to the results, the studied materials seem to be able for manufacturing reabsorbable bone implants.
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