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Medical Implants (medical + implant)
Selected AbstractsMulti-walled Carbon Nanotube-Reinforced Hydroxyapatite Layers on Ti6Al4V Medical Implants by Electrophoretic Deposition (EPD),ADVANCED ENGINEERING MATERIALS, Issue 1-2 2008C. Kaya Sol-gel synthesised nano-size hydroxyapatite (HA) powders were dispersed in water-based suspensions with the addition of multi-walled carbon nanotubes. Ti6Al4V medical alloys were coated with monolithic and carbon nanotube-reinforced HA using electrophoretic deposition (EPD) in an attempt to control deposit structure and thickness. It was shown that the sintering temperature of the deposited HA layers was significantly lowered by the use of sinter active nano-powders. Moreover the addition of carbon nanotubes increased the bonding strength of the EPD-formed layers to the metallic substrate. The cost-effective EPD technique used in the present work has high industrial potential for coating metallic medical implants with composite bioactive layers. [source] Porous silicon as a cell interface for bone tissue engineeringPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2007Wei Sun Abstract A novel cell interface has been constructed on porous silicon. We have demonstrated that nano- to macro-scale porous architectures have promising osteoconductive potentials. Macroporous silicon (pore opening 1,2 µm) is especially favorable for osteoblast adhesion, growth, protein synthesis and mineralization. An electronic/optoelectronic controllable medical implant with both scaffolding and drug delivery functions may be created for orthopaedic tissue engineering with this material. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Influence of Treatment Conditions on the Chemical Oxidative Activity of H2SO4/H2O2 Mixtures for Modulating the Topography of Titanium,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Fabio Variola Abstract Host-tissue integration of medical implants is governed by their surface properties. The capacity to rationally design the surface physico-chemical cues of implantable materials is thus a fundamental prerequisite to confer enhanced biocompatibility. Our previous work demonstrated that different cellular processes are elicited by the nanotexture generated on titanium (cpTi) and Ti6Al4V alloy by chemical oxidation with a H2SO4/H2O2 mixture. Here, we illustrate that by varying the etching parameters such as temperature, concentration, and treatment time, we can create a variety of surface features on titanium which are expected to impact its biological response. The modified submicron and nanotextured surfaces were characterized by scanning electron (SEM) and atomic force (AFM) microscopies. Contact angle measurements revealed the higher hydrophilicity of the modified surfaces compared to untreated samples and Fourier transform infrared spectroscopy (FT-IR) established that the etching generated a TiO2 layer with a thickness in the 40,60,nm range. [source] Multi-walled Carbon Nanotube-Reinforced Hydroxyapatite Layers on Ti6Al4V Medical Implants by Electrophoretic Deposition (EPD),ADVANCED ENGINEERING MATERIALS, Issue 1-2 2008C. Kaya Sol-gel synthesised nano-size hydroxyapatite (HA) powders were dispersed in water-based suspensions with the addition of multi-walled carbon nanotubes. Ti6Al4V medical alloys were coated with monolithic and carbon nanotube-reinforced HA using electrophoretic deposition (EPD) in an attempt to control deposit structure and thickness. It was shown that the sintering temperature of the deposited HA layers was significantly lowered by the use of sinter active nano-powders. Moreover the addition of carbon nanotubes increased the bonding strength of the EPD-formed layers to the metallic substrate. The cost-effective EPD technique used in the present work has high industrial potential for coating metallic medical implants with composite bioactive layers. [source] Penicillium chrysogenum glucose oxidase , a study on its antifungal effectsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2004É. Leiter Abstract Aims:, Purification and characterization of the high molecular mass Candida albicans -killing protein secreted by Penicillium chrysogenum. Methods and Results:, The protein was purified by a combination of ultrafiltration, chromatofocusing and gel filtration. Enzymological characteristics [relative molecular mass (Mr) = 155 000, subunit structure ,2 with Mr,, = 76 000, isoelectric point (pI) = 5·4] were determined using SDS-PAGE and 2D-electrophoresis. N-terminal amino acid sequencing and homology search demonstrated that the antifungal protein was the glucose oxidase (GOX) of the fungus. The enzyme was cytotoxic for a series of bacteria, yeasts and filamentous fungi. Vitamin C (1·0 mg ml,1) prevented oxidative cell injuries triggered by 0·004 U GOX in Emericella nidulans cultures but bovine liver catalase was ineffective even at a GOX : catalase activity ratio of 0·004 : 200 U. A secondary inhibition of growth in E. nidulans cultures by the oxygen-depleting GOX,catalase system was likely to replace the primary inhibition exerted by H2O2. Conclusions:,Penicillium chrysogenum GOX possesses similar enzymological features to those described earlier for other Penicillium GOXs. Its cytotoxicity was dependent on the inherent antioxidant potential of the test micro-organisms. Significance and Impact of the Study:,Penicillium chrysogenum GOX may find future applications in glucose biosensor production, the disinfection of medical implants or in the food industry as an antimicrobial and/or preservative agent. [source] Characterization of the physicochemical, antimicrobial, and drug release properties of thermoresponsive hydrogel copolymers designed for medical device applicationsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008David S. Jones Abstract In this study, a series of hydrogels was synthesized by free radical polymerization, namely poly(2-(hydroxyethyl)methacrylate) (pHEMA), poly(4-(hydroxybutyl)methacrylate) (pHBMA), poly(6-(hydroxyhexyl)methacrylate) (pHHMA), and copolymers composed of N -isopropylacrylamide (NIPAA), methacrylic acid (MA), NIPAA, and the above monomers. The surface, mechanical, and swelling properties (at 20 and 37°C, pH 6) of the polymers were determined using dynamic contact angle analysis, tensile analysis, and thermogravimetry, respectively. The Tg and lower critical solution temperatures (LCST) were determined using modulated DSC and oscillatory rheometry, respectively. Drug loading of the hydrogels with chlorhexidine diacetate was performed by immersion in a drug solution at 20°C ( Role of Orthopedic Implants and Bone Morphology in the Identification of Human RemainsJOURNAL OF FORENSIC SCIENCES, Issue 2 2007Ellie K. Simpson Ph.D. ABSTRACT: When conventional methods of identification, such as visual recognition and dental comparison, cannot be used to identify a deceased person, it becomes necessary to consider alternative methods. The presence of an orthopedic implant in a body may assist identification if ante-mortem medical records are available for comparison. Another method of identification involves comparison of ante-mortem and postmortem radiographs. Eight cases are reported from Forensic Science SA where the presence of orthopedic implants and/or ante-mortem radiographs were used to try to establish identification. In six cases, positive identification was established, and in two cases with upper limb orthopedic implants, the bones remained unidentified. Manufacturers were unable to provide any information about the distribution and use of the implants that could be of use with identification, as there are no requirements in Australia for individual medical implants to be tracked. Such a system has the potential to aid postmortem identification if serial codes were etched onto implants that could then be traced to manufacturers, surgeons, and recipients of these devices. [source] Construction of Polycation-Based Non-Viral DNA Nanoparticles and Polyanion Multilayers via Layer-by-Layer Self-Assembly,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 20 2005Kefeng Ren Abstract Summary: The multilayers of polycation-based non-viral DNA nanoparticles and biodegradable poly(L -glutamic acid) (PGA) were constructed by a layer-by-layer (LbL) technique. Poly(ethyleneimine) (PEI) was used to condense DNA to develop non-viral DNA nanoparticles. AFM, UV-visible spectrometry, and TEM measurements revealed that the PEI-DNA nanoparticles were successfully incorporated into the multilayers. The well-structured, easily processed multilayers with the non-viral DNA nanoparticles may provide a novel approach to precisely control the delivery of DNA, which may have great potential for gene therapy applications in tissue engineering, medical implants, etc. A TEM image of the cross section of a (PGA/PEI-DNA nanoparticle)20 multilayer. [source] Silver nanocluster containing diamond like carbonPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2008F. Schwarz Abstract Applying Diamond Like Carbon (DLC) as medical coating has become well established since large scale plasma processes like Plasma Immersion Ion Implantation and Deposition (PIII&D) are available. Now the focus of research lies on systematic modification of certain biological relevant properties and the most recent field of interest turned to generating antimicrobial behaviour. This is desirable for medical tools as well as for different types of medical implants. Since silver and copper are known to provide a bactericidal effect, one tries to introduce clusters of these noble metals into the carbon matrix. The basic principle of the method presented is to convert a metal containing polymer film into DLC by ion bombardment. In this paper the hydrogenated DLC matrix is characterized and the evolution of the metal particles is studied. By means of film composition (RBS/ERD), bonding structure (Raman spectroscopy) and hardness (nanoindentation), the dependency of these material properties on ion species, energy and fluence is investigated. TEM imaging is used to visualize the film structure. Upon ion irradiation of the polymer films, increased density and considerable loss of hydrogen can be observed, which both are controlled by ion fluence and mass. The crosslinking of the carbon network, caused by hydrogen drive out as well as atomic displacements in collision cascades, results in the formation of a-C:H. The silver particles in the film some ion induced growth, but still remain as nanoclusters in the a-C:H matrix. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]
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