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Biomedical Devices (biomedical + device)
Selected AbstractsSynthesis of Polymerizable Superoxide Dismutase Mimetics to Reduce Reactive Oxygen Species Damage in Transplanted Biomedical Devices,ADVANCED FUNCTIONAL MATERIALS, Issue 20 2008Charles Y. Cheung Abstract A new polymerizable superoxide dismutase (SOD) mimetic metalloporphyrin macromer was synthesized to minimize inflammatory damage associated with tissue transplantation and biomaterial implantation, such as the use of encapsulated pancreatic islets for the treatment of type I diabetes mellitus (TIDM). This functional SOD mimetic, Mn(III) Tetrakis[1-(3-acryloxy-propyl)-4-pyridyl] porphyrin (MnTPPyP-Acryl), was copolymerized and crosslinked with poly(ethylene glycol) diacrylate (PEGDA) to form hydrogel networks that may actively reduce reactive oxygen species (ROS) damage associated with biomaterial implantation. Solution phase activity assays with MnTPPyP-Acryl macromers showed comparable SOD activity to MnTMPyP, a non-polymerizable commercially available SOD mimetic. This work also describes the development of a new, simple, and inexpensive solid phase assay system that was developed to assess the activity of MnTPPyP-Acryl macromers polymerized within PEGDA hydrogels, which has the potential to fulfill an existing void with the biochemical tools available for testing other immobilized ROS antagonists. With this new assay system, hydrogels containing up to 0.25,mol% MnTPPyP-Acryl showed significantly higher levels of SOD activity, whereas control hydrogels polymerized with inactive TPPyP-Acryl macromers showed only background levels of activity. The potential for repeated use of such hydrogel devices to consistently reduce superoxide anion concentrations was demonstrated upon retention of ,100% SOD activity for at least 72,h post-polymerization. These results demonstrate the potential that polymerizable SOD mimetics may have for integration into medical devices for the minimization of inflammatory damage upon transplantation, such as during the delivery of encapsulated pancreatic islets. [source] Recharging the Battery of Implantable Biomedical Devices by LightARTIFICIAL ORGANS, Issue 10 2009Carlos Algora Abstract This article describes a new powering system for implantable medical devices that could significantly increase their lifetime. The idea is based on the substitution of the usual implantable device battery for an electric accumulator (rechargeable battery), which is fed by the electric power generated by a photovoltaic converter inside the implantable device. Light impinges on the photovoltaic device through an optical fiber going from the photovoltaic device to just beneath the patient's epidermis. Light can enter the optical fiber by passing through the skin. A complete power-by-light system has been developed and tested with a real implantable pulse generator for spinal cord stimulation. The feasibility of the proposed system has been evaluated theoretically. For example, after 13 h/week of laser exposure, the lifetime of the implantable device would increase by 50%. Other combinations resulting in lifetime increases of more than 100% are also possible. So, the proposed system is now ready to take a further step forward: in vivo animal testing. [source] Anisotropic Behavior of Radiopaque NiTiPt Hypotube for Biomedical ApplicationsADVANCED ENGINEERING MATERIALS, Issue 11 2009Zhicheng Lin This paper presents the first characterization of anisotropic stress,strain behavior in micron-sized specimens cut directly from hypotubes, the starting material for the manufacture of endovascular stents and other biomedical devices, of a new radiopaque alloy NiTiPt. Experimental results show that NiTiPt hypotube has very different anisotropic characteristics when compared to its NiTi counterpart including higher tensile strength and strain, higher stress,strain nonlinearity, smaller hysteresis loop, and sharper tails during loading,unloading. [source] Inside Front Cover ,Advanced Biomaterials 1/2009ADVANCED ENGINEERING MATERIALS, Issue 3 2009Andrés F. Lasagni The cover picture by Lasagni et. al shows two-dimensional periodic microstructures of polyethylene glycol diacrylate (PEG-DA) fabricated using nanosecond (top) and femtosecond (bellow) multibeam laser interference patterning (MLI). The periodic topography can be varied by simple control of the interference patterns as well as exposure dosages. Such structures with controlled topography are of relevant importance for applications in biomedical devices. [source] Characterization of Ti-Ta Alloys Synthesized by Cold Crucible Levitation Melting,ADVANCED ENGINEERING MATERIALS, Issue 8 2008D.-M. Gordin Ti-Ta alloys are potentially interesting for many applications including chemistry industries, marine environment and biomedical devices. In this study, the Ti-Ta alloys were synthesized by cold crucible levitation melting (CCLM) in the whole range of composition. The different microstructures were characterized by X-ray diffraction and optical microscopy, the ,-transus was detected by electrical resistivity, the mechanical properties were evaluated by compression tests and microhardness measurements and the electrochemical behavior was carried out in Ringer's solution. [source] Design of Multiresponsive Hydrogel Particles and AssembliesADVANCED FUNCTIONAL MATERIALS, Issue 11 2010Grant R. Hendrickson Abstract In the realm of soft nanotechnology, hydrogel micro- and nanoparticles represent a versatile class of responsive materials. Over the last decade, our group has investigated the synthesis and physicochemical properties of a variety of synthetic hydrogel particles. From these efforts, several particle types have emerged with potentially enabling features for biological applications, including nanogels for targeted drug delivery, microlenses for biosensing, and coatings for biomedical devices. For example, core/shell nanogels have been used to encapsulate and deliver small interfering RNA to ovarian cancer cells; nanogels used in this fashion may improve therapeutic outcomes for a variety of macromolecular therapeutics. Microgels arranged as multilayers on implantable biomaterials greatly minimize the host inflammatory response to the material. Furthermore, the triggered release of drugs (i.e., insulin) has been demonstrated from similar assemblies. The goal of this feature article is to highlight developments in the design of responsive microgels and nanogels in the context of our recent efforts and in relation to the community that has grown up around this fascinating class of materials. [source] Multifunctional Nanobiomaterials for Neural InterfacesADVANCED FUNCTIONAL MATERIALS, Issue 4 2009Mohammad Reza Abidian Abstract Neural electrodes are designed to interface with the nervous system and provide control signals for neural prostheses. However, robust and reliable chronic recording and stimulation remains a challenge for neural electrodes. Here, a novel method for the fabrication of soft, low impedance, high charge density, and controlled releasing nanobiomaterials that can be used for the surface modification of neural microelectrodes to stabilize the electrode/tissue interface is reported. The fabrication process includes electrospinning of anti-inflammatory drug-incorporated biodegradable nanofibers, encapsulation of these nanofibers by an alginate hydrogel layer, followed by electrochemical polymerization of conducting polymers around the electrospun drug-loaded nanofibers to form nanotubes and within the alginate hydrogel scaffold to form cloud-like nanostructures. The three-dimensional conducting polymer nanostructures significantly decrease the electrode impedance and increase the charge capacity density. Dexamethasone release profiles show that the alginate hydrogel coating slows down the release of the drug, significantly reducing the burst effect. These multifunctional materials are expected to be of interest for a variety of electrode/tissue interfaces in biomedical devices. [source] Multiple Functionalities of Polyelectrolyte Multilayer Films: New Biomedical ApplicationsADVANCED MATERIALS, Issue 4 2010Thomas Boudou Abstract The design of advanced functional materials with nanometer- and micrometer-scale control over their properties is of considerable interest for both fundamental and applied studies because of the many potential applications for these materials in the fields of biomedical materials, tissue engineering, and regenerative medicine. The layer-by-layer deposition technique introduced in the early 1990s by Decher, Moehwald, and Lvov is a versatile technique, which has attracted an increasing number of researchers in recent years due to its wide range of advantages for biomedical applications: ease of preparation under "mild" conditions compatible with physiological media, capability of incorporating bioactive molecules, extra-cellular matrix components and biopolymers in the films, tunable mechanical properties, and spatio-temporal control over film organization. The last few years have seen a significant increase in reports exploring the possibilities offered by diffusing molecules into films to control their internal structures or design "reservoirs," as well as control their mechanical properties. Such properties, associated with the chemical properties of films, are particularly important for designing biomedical devices that contain bioactive molecules. In this review, we highlight recent work on designing and controlling film properties at the nanometer and micrometer scales with a view to developing new biomaterial coatings, tissue engineered constructs that could mimic in vivo cellular microenvironments, and stem cell "niches." [source] Nanobiomaterials and Nanoanalysis: Opportunities for Improving the Science to Benefit Biomedical Technologies,ADVANCED MATERIALS, Issue 5 2008W. Grainger Abstract Nanomaterials advocated for biomedical applications must exhibit well-controlled surface properties to achieve optimum performance in complex biological or physiological fluids. Dispersed materials with extremely high specific surface areas require as extensive characterization as their macroscale biomaterials analogues. However, current literature is replete with many examples of nanophase materials, most notably nanoparticles, with little emphasis placed on reporting rigorous surface analysis or characterization, or in formal implementation of surface property standards needed to validate structure-property relationships for biomedical applications. Correlations of nanophase surface properties with their stability, toxicity and biodistributions are essential for in vivo applications. Surface contamination is likely, given their processing conditions and interfacial energies. Leaching adventitious adsorbates from high surface area nanomaterials is a possible toxicity mechanism. Polydimethylsiloxane (PDMS), long known as a ubiquitous contaminant in clean room conditions, chemical synthesis and microfabrication, remains a likely culprit in nanosystems fabrication, especially in synthesis, soft lithography and contact molding methods. New standards and expectations for analyzing the interfacial properties of nanoparticles and nano-fabricated technologies are required. Surface science analytical rigor similar to that applied to biomedical devices, nanophases in microelectronics and heterogeneous catalysts should serve as a model for nanomaterials characterization in biomedical technologies. [source] Cover Picture: Multipotent Polymer Coatings Based on Chemical Vapor Deposition Copolymerization (Adv. Mater.ADVANCED MATERIALS, Issue 12 200612/2006) Abstract The cover shows that chemical vapor deposition can be used to prepare copolymer thin films, on varying substrates, that can bind two different ligands with high selectivity. In work reported by Lahann and co-workers on p.,1521, the actual ligand ratios on the surface can be controlled by varying the copolymer composition. This technology may find applications in biomedical devices, high-throughput screening platforms, microfluidic analysis devices, and diagnostic platforms. [source] Biodegradable polymers: An updateISRAEL JOURNAL OF CHEMISTRY, Issue 4 2005Ariella Shikanov The use of polymeric materials for the administration of pharmaceuticals, and as biomedical devices has increased dramatically. This review focuses on synthetic biodegradable polymers of current interest for medical use, based on ester and anhydride bonds. Special attention is given to factors affecting biodegradation, including: polymer structure, morphology, molecular weight, radiation, and chemical treatment, as well as the effects of drugs and plasticizers added to the polymer mass. The toxicity and biocompatibility of the polymers and their current and future applications in medicine are also briefly reviewed. [source] Overview of polymer micro/nanomanufacturing for biomedical applicationsADVANCES IN POLYMER TECHNOLOGY, Issue 4 2008Allen Y. Yi Abstract Micro/nanotechnology is initiated from the electronics industry. In recent years, it has been extended to micro/nanoelectromechanic system for producing miniature devices based on silicon and semiconductor materials. However, the use of these hard materials alone is inappropriate for many biomedical devices. Soft polymeric materials possess many attractive properties such as high toughness and recyclability. Some possess excellent biocompatibility, are biodegradable, and can provide various biofunctionalities. Proper combinations of micro/nanoelectronics, polymers, and biomolecules can lead to new and affordable medical devices. In this paper, we briefly review several cleanroom and noncleanroom techniques related to micro/nanomanufacturing of polymeric materials. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:188,198, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20134 [source] Bacterial adhesion to diamond-like carbon as compared to stainless steelJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Antti Soininen Abstract Recent studies suggest that diamond-like carbon (DLC) coatings are suitable candidates for application on biomedical devices and implants, due to their high hardness, low friction, high wear and corrosion resistance, chemical inertness, smoothness, and tissue and blood compatibility. However, most studies have neglected the potential susceptibility of DLC coatings to bacterial adhesion, which is the first step in the development of implant-related infections. This study compares adhesion of seven bacterial strains, commonly implicated in implant-related infections, to tetrahedral amorphous carbon, with their adhesion to AISI 316L surgical steel. The results show that bacterial adhesion to DLC was similar to the adhesion to commonly used stainless steel. This suggests that DLC coating can be advantageously used on implants made of AISI 316L or other materials without increasing the risk to implant-related infections. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] A fracture-mechanics-based approach to fracture control in biomedical devices manufactured from superelastic Nitinol tubeJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2008S. W. Robertson Abstract Several key fracture-mechanics parameters associated with the onset of subcritical and critical cracking, specifically the fracture toughness, crack-resistance curve, and fatigue threshold, have recently been reported for the superelastic alloy Nitinol, in the product form of the thin-walled tube that is used to manufacture several biomedical devices, most notably endovascular stents. In this study, we use these critical parameters to construct simple decision criteria for assessing the quantitative effect of crack-like defects in such Nitinol devices with respect to their resistance to failure by deformation or fracture. The criteria are based on the (equivalent) crack-initiation fracture toughness and fatigue threshold stress-intensity range, together with the general yield strength and fatigue endurance strength, and are used to construct a basis for design against single-event (overload) failures as well as for time-/cycle-delayed failures associated with fatigue. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008 [source] The Midas Touch: Surface Processing With the UV Excimer LaserLASER TECHNIK JOURNAL, Issue 1 2009Drive Disruptive Innovations, Open Up Growth Markets Very much like the ancient king Midas who as the legend tells was able to transform ordinary material into gold by the touch of his hand, today's excimer lasers are capable of transforming an unspecificmaterial layer into a high value, functional surface by their unique beam properties. Representing today's most cost-effective and dependable pulsed, ultraviolet (UV) laser technology, excimer lasers enable disruptive innovation in various growth industries as diverse as the markets for flat panel displays, automobiles, biomedical devices and alternative energies. It is the combination of two fundamental aspects, namely wavelength and output power, which determines the excimer laser's unique value adding potential in high tech industries which more than ever have to balance product size-efficiency and performance demands with process speed and production costs. This article will try to provide an insight into some key applications of the excimer laser. [source] | |||||||||||||