Papers by Keyword: Ion Release

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Authors: Fei Long Nie, Yan Bo Wang, Shi Cheng Wei, Yu Feng Zheng, Sheng Gang Wang
Abstract: Bulk nanocrystalline 304 stainless steel (nanocrystalline 304ss) discs had been successfully prepared by the commercial microcrystalline 304 stainless steel (microcrystalline 304ss) plate using severe rolling technique. Micro-hardness was measured to reveal the different mechanical behavior after the severe plastic deformation. The electrochemical corrosion resistance and ion release behavior after immersion of the samples were investigated in Hank’s solution for its potential use as implant and orthodontic appliance in body. Furthermore, murine fibroblast cells were indirectly employed to detect cytotoxicity by co-incubation with the extraction from the given materials. Haemocompatibility, consisting of hemolysis test and adhesion of the platelets, was also measured with fresh human whole blood and platelet-rich plasma respectively. Polarization resistance trials indicate that nanocrystalline 304ss is more corrosion resistant in the Hank’s solution, with lower current density and superficial corrosion morphologies. The release values of the biotoxic ions after immersion do not exceed the set limit and turn to be well below the critical value necessary to induce allergy and below daily dietary intake level. Cellular interaction is observed via the proliferated feature of the cell line. Hemolysis and platelet adhesion results elucidates that nanocrystalline 304ss is biological and hematologic compatible.
Authors: Drago Skrtic, S.Y. Lee, Joseph M. Antonucci, D.W. Liu
Abstract: This study explores how a) the resin grafting potential for amorphous calcium phosphate (ACP) and b) particle size of ACP affects physicochemical properties of composites. Copolymers and composites were evaluated for biaxial flexure strength (BFS), degree of vinyl conversion (DC), mineral ion release and water sorption (WS). Milled ACP composites were superior to unmilled ACP composites and exhibited 62 % and 77 % higher BFS values (dry and wet state, respectively). The average DC of copolymers 24 h after curing was 80 %. DC of composites decreased 10.3 % for unmilled Zr-ACP and 4.6 % for milled Zr-ACP when compared to the corresponding copolymers. The WS increased as follows: copolymers < milled Zr-ACP composites < unmilled Zr-ACP composites. The levels of Ca and PO4 released from both types of composites increased with the increasing EBPADMA/TEGDMA ratio in the matrix. They were significantly above the minimum necessary for the redeposition of HAP to occur. No significant consumption of released calcium by the carboxylic groups of methacryloxyethyl phtahalate (MEP) occurred at a mass fraction of 2.6 % of MEP in the resin. Improvements in ACP composite’s physicochemical properties are achieved by fine tuning of the resin and improved ACP’s dispersion within the polymer matrix after ball-milling.
Authors: Joni Korventausta, Ari Rosling, Jenny Andersson, Anna Lind, Mika Linden, Mika Jokinen, Antti Yli-Urpo
Authors: Jian Feng Zhang, Ya Xiong Deng, Zhan Qin Lei, Wei Xie
Abstract: In the past two decade, the Chinese government has paid a huge effort to solve the problem of drinking water in remote rural. As an alterative success case, rainwater harvesting and utility has been the most efficient way to supplying fresh water in rural areas of the Loess Plateau, a typical water resources serious shortage area in China. Focused on improving the quality of the rural village cistern water, study about the characteristics of ion release from building materials during runoff process with five representative materials used for rainwater collection: concrete, red brick, grey tile, red tile and soil was conducted. The ion releasing process and following effect on cistern water quality index, such as hardness, pH, conductivity, has been analyzed. Results revealed that the most release strength of different materials was arriving at 30s following startup. Furthermore, the test of effects of rain acidity on ion release procession showed that the total ion release increased with storm water pH declining, however, the release strength was irrelevance with runoff’s pH. Based on research results, a detailed suggestion was provided to renovate intake construction of cistern for improving the drinking water quality in remote rural areas of Weibei Semi-arid District.
Authors: Siti Hafizah Mohamad, Mohd Al Amin Muhamad Nor
Abstract: The effect addition of Na2O on the solubility properties of phosphate glass of the composition, 45P2O5-18CaO-xNa2O-(34-x)K2O-6Al2O3, where x = 0,5,10,15 and 20 wt. %. has been studied. Glass transition temperature (Tg) of glass samples, weight loss and pH of the immersion solution were measured. The Tg value of the phosphate glass also decreased with the incorporation of Na2O up to 10 wt. % and increased with the incorporation of 15 and 20 wt. %. These results indicates that the solubility and Tg value of phosphate glass were highly influence by the glass composition. The substitution of Na2O to the phosphate glass system with the present of K2O has decrease the solubility of phosphate glass. The released of phosphate and calcium ion seem to decrease with the increasing of Na2O content in the glass composition.
Authors: Min Chul Kim, Kyoung Nam Kim, Kwang Mahn Kim, Seong Ho Choi, Chong Kwan Kim, Racquel Z. LeGeros, Yong Keun Lee
Abstract: The development of phosphate glasses for use in orthopaedic implants has attracted much interest because their chemical and physical properties make them suitable for use as bone-bonding materials. We prepared various compositions of CaO-P2O5-MO or CaO-P2O5-M2O (M: K, Li, Na, Mg, Zn) glasses to measure ion release, solubility and bioactivity. The compositions with (Ca,M)/P molar ratio 0.6 were fixed P2O5 mol% content at 45.45 mol%, and varying MO or M2O mol% at 10, 20 and 30 mol%. Ca2+ ion release properties were investigated in 0.1M potassium acetate with pH 6 at 37oC by immersing 50 mg of powder into 100 ml of acidic buffer solution. The highest and lowest extent of released Ca2+ ion was observed for composition with 10 mol% of K2O and 30 mol% of MgO, respectively. The weight loss in distilled water at 37oC was measured. Solubility increased with decreasing CaO content, but decreased with increasing MgO content. Bioactivity in the simulated body fluid at 37oC was measured.
Authors: Minna Malin, Joni Korventausta, Ville Meretoja, Jukka Seppälä
Abstract: A series of ceramic-polymer scaffolds were studied for bone tissue engineering applications. These applications require bone reactivity as well as suitable scaffold properties and structure. Bioactive glass (BAG) and sol-gel derived silicas were chosen for ceramic components of the scaffolds, and crosslinked poly(ε-caprolactone/D,L-lactide) copolymers with monomer ratios 90/10 and 70/30 were used as polymer matrices. Scaffolds were prepared by photo-curing crosslinkable oligomers in the presence of the ceramic component and porosity producing salt. Scaffolds with 60-80 vol-% continuous phase macroporosity were obtained by using calcium chloride hexahydrate (CaCl2⋅6H2O), and were further tested in simulated body fluid (SBF). The ceramics remained highly reactive during scaffold preparation resulting in in vitro calcium phosphate formation.
Authors: Janusz Szewczenko, Anna Zabuga, Marcin Kaczmarek, Marcin Basiaga, Wojciech Kajzer, Zbigniew Paszenda, Katarzyna Nowińska
Abstract: The influence of bone union activation realized with the use of the low-intensity pulsed ultrasound (LIPUS) on degradation of titanium alloys was presented in the work. Ti6Al4V ELI and Ti6Al7Nb alloy samples of modified surface layer were used in the study. The preliminary surface treatments were: grinding, vibration machining, mechanical polishing, sandblasting and electrochemical polishing. The final procedures of the surface modification were anodization and steam sterilization. The scope of the work included the study of pitting corrosion resistance and concentration of metal ions released to the Ringer’s solution. The study was performed for the undeformed and deformed samples subjected to the influence of ultrasound. The reference samples were the samples kept in the solution and not having the impact of ultrasound. On the basis of the study it was found that the conditions for bone union stimulation by low intensity pulsed ultrasound do not initiate pitting corrosion of the titanium alloy samples, although they increase the mass of ions released from the surface to the solution.
Authors: A.Ansari Hamedani, F. Moztarzadeh, D. Bizari, M. Ashuri, M. Tahriri
Abstract: Bioactive glasses not only can bond to hard tissues of the body, are also able to release ions that have stimulatory effects on cells and so are regarded as promising candidate materials for gene activating purposes in tissue engineering applications. In this research the effect of co-substitution of Magnesium and Zinc for Calcium on bioactivity of binary sol-gel derived glass 70S30C (70 mol. % SiO2, 30 mol. % CaO) was investigated. Calcium phosphates forming ability tests and investigation of glass degradation products in simulated body fluid (SBF) were performed as follows.After sol-gel synthesis of glass powders of comparable and under 38 μm particle size distributions, their state of being amorphous was investigated using X-ray diffraction. Then for in vitro investigation of bioactivity, ion release, pH change and Calcium phosphate formation during immersion of glass powders in SBF at 37 ͦ C up to 2 weeks were studied. Infrared spectroscopy was performed on the reacted glass powders.Results indicate that substitution of Zinc for Calcium suppresses crystalline apatite formation more effectively than substitution of Magnesium for Calcium and help us design modified compositions of magnesium and zinc containing bioactive glasses that can find applications in bone and also cartillage tissue engineering.
Authors: Marius Niculescu, Dan Laptoiu, Florin Miculescu, Iulian Vasile Antoniac
Abstract: Total hip prosthese are widely used in total hip arthroplasty, offering many benefit to patients with different articular diseases like osteoarthritis or after different accidents. Many total hip prosthesis are now available to the orthopaedic surgeons to replace the hip articulation, with different design and with components made by different type of biomaterials: metallic (cobalt-chrome and titanium alloys, zirconium-niobium alloy named oxinium), ceramic (alumina, zirconia), polymers (ultra high weight molecular polyethylene-UHMWPE). Even total hip arthroplasty has a high success rate, implant loosening may occur, with different symptoms that could be attributed to metal allergy. Because the stem components of the total hip prosthesis are made by metallic biomaterials, many papers describe the adverse effects related to the release of metal ions (like cytotoxicity, carcinogenicity and metal allergy). There are different types of metal corrosion: intergranular, pitting, crevice, fatigue, stress, fretting, and galvanic. On the other hand, in many cases (like metal-on-metal prosthesis) appear corrosion and wear between two metallic components. This processes are favourable for the aparition of hypersensitivity-related tissue reactions. Especially some metallic ions (nickel, cobalt, and chromium) presents in stainless steels and cobalt-chromium alloys are most known to be released from prostheses components and give metal allergy. Of course, during the time was developped some solutions in order to improve the performance of the hip prostheses components made by metallic components like coating with thin layers using different biomaterials like porous titanium or hydroxiapatite. The aims of this review article were to explore mainly the relationship between corrosion products and implant-related hypersensitivity, the importance of surface treatment for metallic components, try define the effect of metal ion concentrations, and differentiate between allergy and infection in total hip replacement. The long-term performance of the coated components will be also analyzed and synthetic described based on clinical results. Also, some relevant aspects from our clinical experience and retrieved prosthesis analysis using stereomicroscopy and scanning electron microscopy will be shown in order to support the conclusions.
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