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Medical Devices (medical + device)
Kinds of Medical Devices Selected AbstractsPediatric Interventional Cardiology in the United States is Dependent on the Off-label Use of Medical DevicesCONGENITAL HEART DISEASE, Issue 1 2010Jamie S. Sutherell MD ABSTRACT Objective., A substantial unmet medical device need exists in pediatric care. As a result, the off-label use of approved devices is routine in pediatric interventional cardiology, but the extent and nature of this practice has not been previously described. The purpose of this study, therefore, is to evaluate the prevalence and nature of off-label cardiac device use in an active pediatric interventional program in the United States. Study Design., This study is a retrospective review of all interventional cardiac procedures performed at our institution from July 1, 2005 to June 30, 2008. Diagnostic (noninterventional) catheterizations, myocardial biopsies, invasive electrophysiology studies, and studies involving investigational devices were excluded. Interventions performed were compared with the manufacturer's labeled indications for each device. Results., During this 3-year period, 473 patients (median age 4.1 years) underwent 595 transcatheter interventions. An approved device was utilized for an off-label application in 63% of patients, and in 50% of all interventions performed. The most frequent off-label procedures were stent implantations (99% off-label), balloon dilations (78% off-label), and coil embolizations (29% off-label). In contrast, the off-label use of septal and ductal occluders was relatively uncommon. Conclusions., In our routine (noninvestigational) practice of pediatric interventional cardiology, 63% of patients underwent procedures utilizing medical devices for off-label indications. These data underscore the need to enhance cardiac device review and approval processes in the United States to include pediatric applications. [source] Body Computing: How Networked Medical Devices Can Solve Problems Facing Health Care TodayJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2007LESLIE A. SAXON M.D. No abstract is available for this article. [source] Electronic Security Systems and Active Implantable Medical DevicesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2002WERNER IRNICH IRNICH, W.: Electronic Security Systems and Active Implantable Medical Devices. How do active implantable medical devices react in the presence of strong magnetic fields in the frequency range between extremely low frequency (ELF) to radiofrequency (RF) as they are emitted by electronic security systems (ESS)? There are three different sorts of ESSs: electronic article surveillance (EAS) devices, metal detector (MDS) devices, and radiofrequency identification (RFID) systems. Common to all is the production of magnetic fields. There is an abundance of literature concerning interference by ESS gates with respect to if there is an influence possible and if such an influence can bear a risk for the AIMD wearers. However, there has been no attempt to study the physical mechanism nor to develop a model of how and under which conditions magnetic fields can influence pacemakers and defibrillators and how they could be disarmed by technological means. It is too often assumed that interference of AIMD with ESS is inevitable. Exogenous signals of similar intensity and rhythm to heart signals can be misinterpreted and, thus, confuse the implant. Important for the interference coupling mechanism is the differentiation between a "unipolar" and a "bipolar" system. With respect to magnetic fields, the left side implanted pacemaker is the most unfavorable case as the lead forms approximately a semicircular area of maximum 225 cm2 into which a voltage can be induced. This assumption yields an interference coupling model that can be expressed by simple mathematics. The worst-case conditions for induced interference voltages are a coupling area of 225 cm2 that is representative for a large human, a homogeneous magnetic field perpendicular to the area formed by the lead, and a unipolar ventricular pacemaker system that is implanted on the left side of the thorax and has the highest interference sensitivity. In bipolar systems the fields must be 17 times larger when compared to a unipolar system to have the same effect. The magnetic field for interfering with ICDs must be 1.7 stronger than that of the most sensitive unipolar pacemaker. The lowest interference thresholds measured over the last 10 years in the low frequency range (16 2/3 Hz,24 kHz) together with thresholds > 24 kHz that were supplied by the CETECOM study are listed. Both sets of data together with the coupling model, allow for judging which fields of ESSs could influence AIMDs. From measurements at gate antennas, it is possible to derive a "maximum allowed field" curve over the whole frequency range, below which no interference will occur. Comparison of data from literature with these maximum allowed fields confirm the correctness of the calculations. Thus, it is possible to predict interference situations in gates if the magnetic field is known. If all future pacemakers were to have the immunity against interference of the better 50% of today's pacemakers, the magnetic field ceiling values could be at least four times higher. The same is true if the ventricular sensitivity is routinely set at 7 mV. Pacemaker manufacturers should consider filter improvement with modern technology, but gate manufacturers should not claim the privilege of being out of bounds. [source] A Novel Low Temperature Transcutaneous Energy Transfer System Suitable for High Power Implantable Medical Devices: Performance and Validation in SheepARTIFICIAL ORGANS, Issue 5 2010Thushari D. Dissanayake Abstract Transcutaneous energy transfer (TET) systems use magnetic fields to transfer power across the skin without direct electrical connectivity. This offers the prospect of lifetime operation and overcomes risk of infection associated with wires passing through the skin. Previous attempts at this technology have not proved suitable due to poor efficiency, large size, or tissue damage. We have developed a novel approach utilizing frequency control that allows for wide tolerance in the alignment between internal and external coils for coupling variations of 10 to 20 mm, and relatively small size (50 mm diameter, 5 mm thickness). Using a sheep experimental model, the secondary coil was implanted under the skin in six sheep, and the system was operated to deliver a stable power output to a 15 W load continuously over 4 weeks. The maximum surface temperature of the secondary coil increased by a mean value of 3.4 ± 0.4°C (±SEM). The highest absolute mean temperature was 38.3°C. The mean temperature rise 20 mm from the secondary coil was 0.8 ± 0.1°C. The efficiency of the system exceeded 80% across a wide range of coil orientations. Histological analysis revealed no evidence of tissue necrosis or damage after four weeks of operation. We conclude that this technology is able to offer robust transfer of power to implantable devices without excess heating causing tissue damage. [source] Institutional Review Board Approval for Clinical Application of New Medical Devices Rather Than Government AgencyARTIFICIAL ORGANS, Issue 12 2004Ph.D. Emeritus Editor in Chief, Yukihiko Nosé M.D. No abstract is available for this article. [source] Human exposure to phthalates via consumer productsINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2006TED SCHETTLER Summary Phthalate exposures in the general population and in subpopulations are ubiquitous and widely variable. Many consumer products contain specific members of this family of chemicals, including building materials, household furnishings, clothing, cosmetics, pharmaceuticals, nutritional supplements, medical devices, dentures, children's toys, glow sticks, modelling clay, food packaging, automobiles, lubricants, waxes, cleaning materials and insecticides. Consumer products containing phthalates can result in human exposures through direct contact and use, indirectly through leaching into other products, or general environmental contamination. Historically, the diet has been considered the major source of phthalate exposure in the general population, but all sources, pathways, and their relative contributions to human exposures are not well understood. Medical devices containing di-(2-ethylhexyl) phthalate are a source of significant exposure in a susceptible subpopulation of individuals. Cosmetics, personal care products, pharmaceuticals, nutritional supplements, herbal remedies and insecticides, may result in significant but poorly quantified human exposures to dibutyl phthalate, diethyl phthalate, or dimethyl phthalate. Oven baking of polymer clays may cause short-term, high-level inhalation exposures to higher molecular weight phthalates. [source] Optimization of a novel headspace,solid-phase microextraction,gas chromatographic method by means of a Doehlert uniform shell design for the analysis of trace level ethylene oxide residuals in sterilized medical devicesBIOMEDICAL CHROMATOGRAPHY, Issue 6 2009Michael P. DiCicco Abstract Medical devices sterilized by ethylene oxide (EtO) retain trace quantities of EtO residuals, which may irritate patients' tissue. Reliably quantifying trace level EtO residuals in small medical devices requires an extremely sensitive analytical method. In this research, a Doehlert uniform shell design was utilized in obtaining a response surface to optimize a novel headspace,solid-phase microextraction,gas chromatographic (HS-SPME-GC) method developed for analyzing trace levels of EtO residuals in sterilized medical devices, by evaluating sterilized, polymer-coated, drug-eluting cardiovascular stents. The effects of four independent experimental variables (HS-SPME desorption time, extraction temperature, GC inlet temperature and extraction time) on GC peak area response of EtO were investigated simultaneously and the most influential experimental variables determined were extraction temperature and GC inlet temperature, with the fitted model showing no evidence of lack-of-fit. The optimized HS-SPME-GC method demonstrated overall good linearity/linear range, accuracy, repeatability, reproducibility, absolute recovery and high sensitivity. This novel method was successfully applied to analysis of trace levels of EtO residuals in sterilized/aerated cardiovascular stents of various lengths and internal diameter, where, upon heating, trace EtO residuals fully volatilized into HS for extraction, thereby nullifying matrix effects. As an alternative, this novel HS-SPME-GC method can offer higher sensitivity compared with conventional headspace analyzer-based sampling. Copyright © 2009 John Wiley & Sons, Ltd. [source] Management Strategies for Stage-D Patients with Acute Heart FailureCLINICAL CARDIOLOGY, Issue 7 2008David Feldman M.D., Ph.D. Abstract Heart Failure (HF) accounted for 3.4 million ambulatory visits in 2000. Current guidelines from the American Heart Association/American College of Cardiology, the Heart Failure Society of America, and the International Society for Heart & Lung Transplantation recommend aggressive pharmacologic interventions for patients with HF. This may include a combination of diuretics, Angiotensin Converting Enzyme inhibitors, ,-blockers, angiotensin receptor blockers, aldosterone antagonists, and digoxin. Nitrates and hydralazine are also indicated as part of standard therapy in addition to ,-blockers and Angiotensin Converting Enzyme inhibitors, especially but not exclusively, for African Americans with left ventricular (LV) systolic dysfunction. For those with acute decompensated HF, additional treatment options include recombinant human B-type natriuretic peptide, and in the future possible newer agents not yet approved for use in the U.S., such as Levosimendan. Medical devices for use in patients with advanced HF include LV assist devices, cardiac resynchronization therapy, and implantable cardioverter defibrillators. For refractory patients, heart transplantation, the gold-standard surgical intervention for the treatment of refractory HF, may be considered. Newer surgical options such as surgical ventricular restoration may be considered in select patients. Copyright © 2007 Wiley Periodicals, Inc. [source] Near Painless, Nonablative, Immediate Skin Contraction Induced by Low-Fluence Irradiation with New Infrared Device: A Report of 25 PatientsDERMATOLOGIC SURGERY, Issue 5 2006JAVIER RUIZ-ESPARZA MD BACKGROUND Nonablative radiofrequency (NARF) has been the only method for producing noninvasive skin tightening. Nevertheless, significant pain during the procedure is an important downside of this technology. A new nonablative medical device, Titan (Cutera, Inc., Brisbane, CA, USA), capable of fluences much lower than those possible with NARF, was tested as a less painful alternative. OBJECTIVES To produce skin contraction leading to lifting of eyebrows and/or improvement of lower face and neck skin laxity using fluences below pain levels. PATIENTS AND METHODS Twenty-five patients were treated. Standardized photographs were obtained preoperatively, after a few days, a few weeks, and up to 12 months after the procedure. RESULTS Immediate changes were obtained in 22 of 25 patients. Examination of photographs revealed that the initial improvement was maintained throughout the follow-up period. CONCLUSION Immediate true skin contraction persisting through the immediate, intermediate, and long-term follow-up was found in the vast majority of patients in this group. Edema as an artifact simulating immediate improvement was excluded by serial photographs taken during the follow-up period. Skin contraction occurred at low fluences, below the threshold of pain. This, to the best of our knowledge, has not been previously described in the medical literature. [source] Fas/FasL interaction: A novel immune therapy approach with immobilized biologicals,MEDICINAL RESEARCH REVIEWS, Issue 3 2005Martin Scholz Abstract Systemically applied agents to modulate the Fas/FasL system, e.g., by stimulation of Fas on activated leukocytes or tumor cells failed as strategies in immune therapy due to severe toxic effects in the host. Recently, a novel strategy has been developed by using immobilized immune active biologicals in a medical device that may allow immune management without expensive systemic therapy. This review reports on the potential role of Fas/FasL in immune therapy and summarizes current experimental and clinical data with the leukocyte inhibition module (LIM), an immobilized anti-Fas antibody containing device yet used in extracorporeal blood circulation. This proof of principal may stimulate the development of other devices based on the regulation of Fas/FasL or other targets relevant for immune disorders. © 2004 Wiley Periodicals, Inc. [source] Planar inverted-F antennas on implantable medical devices: Meandered type versus spiral typeMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2006Jaehoon Kim Abstract Based on a planar inverted-F antenna (PIFA) configuration, two different shaped (meandered and spiral) antennas are designed using finite-difference time-domain (FDTD) simulations and measurement results. The antennas are installed on an implantable medical device in a biological-tissue simulating model. The impedance-matching and radiation characteristics of two PIFAs are compared in order to observe which shape is more appropriate for wireless communication links of implantable medical devices. Additionally, the effects of the human skin's thickness on the antennas are studied in order to consider medical devices which are implanted in various subcutaneous tissues. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 567,572, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21409 [source] Are Implantable Loop Recorders Useful in Detecting Arrhythmias in Children with Unexplained Syncope?PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2009KHALID N. AL DHAHRI M.B.B.S. Introduction: Syncope and presyncope are symptoms that occur infrequently in children, are unpredictable, and represent a diagnostic challenge to the physician. Conventional diagnostic investigations are often unable to establish a diagnosis, making it difficult to determine patient risk and direct appropriate therapy. The implantable loop recorder (ILR) is a medical device that was created for prolonged monitoring of heart rate and rhythm and has been used in a limited number of pediatric studies in which the cause of the syncope is unknown. Methods: This is a retrospective review of the clinical, surgical, and follow-up data of patients who had ILR devices implanted after conventional testing failed to identify a cause for their symptoms. Results: The diagnostic yield of the ILR device in unmasking the cause for symptoms in our patient cohort was 64%. In our study, manually activated events accounted for 71% of all documented episodes and 68% of the cases involving hemodynamically important arrhythmias or transient rhythm changes. The ILR device can be safely implanted and explanted in children without significant morbidity, in most cases. None of our patients experienced any long-term adverse events associated with placement of the device and all were alive at last follow-up. Conclusions: The use of the ILR device is a useful tool to help unmask arrhythmias as a cause of unexplained syncope in children. Patient selection for who should and should not have an ILR device implanted will continue to influence its diagnostic utility and generate controversy among stakeholders. [source] Prospective evaluation in children of a new medical device intended to insure the correct administration of intrathecal antineoplastic agentsPEDIATRIC BLOOD & CANCER, Issue 1 2003A. Lecomte PharmD No abstract is available for this article. [source] Comparing Accuracy in an Unpaired Post-market Device Study with Incomplete Disease AssessmentBIOMETRICAL JOURNAL, Issue 3 2009Todd A. Alonzo Abstract The sensitivity and specificity of a new medical device are often compared relative to that of an existing device by calculating ratios of sensitivities and specificities. Although it would be ideal for all study subjects to receive the gold standard so true disease status was known for all subjects, it is often not feasible or ethical to obtain disease status for everyone. This paper proposes two unpaired designs where each subject is only administered one of the devices and device results dictate which subjects are to receive disease verification. Estimators of the ratio of accuracy and corresponding confidence intervals are proposed for these designs as well as sample size formulae. Simulation studies are performed to investigate the small sample bias of the estimators and the performance of the variance estimators and sample size formulae. The sample size formulae are applied to the design of a cervical cancer study to compare the accuracy of a new device with the conventional Pap smear. [source] Causes of near misses in critical care of neonates and childrenACTA PAEDIATRICA, Issue 3 2008O Tourgeman-Bashkin Abstract Aim: The primary goal of this study was to examine the nature and causes of medical errors known as almost adverse events (AAEs) and potential adverse events (PAEs) in intensive care units. Methods: Observations were conducted in the Neonatal Intensive Care Unit and in the Pediatric Intensive Care Unit in a large hospital in Israel. The AAEs and PAEs were classified into three main categories: environmental, system and human factors. Data encoding and analysis was based on a Bayesian model previously developed to analyse causes of traffic accidents, and the categories were based on systems and ergonomics approaches. Results: ,Workload' (a system factor) was the main cause of AAEs and ,communication failures' (a human factor) was the second main cause of AAEs. Among the environmental factors, ,failures in medical devices' was the most cited cause of AAEs. Environmental factors accounted for most of PAEs and among them ,form failures' was the most ,AAE'-prone factor. Conclusions: Environmental factors (mainly ,failures in medical device') and system factors (mainly ,workload') accounted for most of AAEs in the intensive care units studied. The systems and the ergonomics approaches to error analysis can be useful in creating a comprehensive error management programme in order to minimize the gap between work demands and individual capabilities. [source] Pediatric Interventional Cardiology in the United States is Dependent on the Off-label Use of Medical DevicesCONGENITAL HEART DISEASE, Issue 1 2010Jamie S. Sutherell MD ABSTRACT Objective., A substantial unmet medical device need exists in pediatric care. As a result, the off-label use of approved devices is routine in pediatric interventional cardiology, but the extent and nature of this practice has not been previously described. The purpose of this study, therefore, is to evaluate the prevalence and nature of off-label cardiac device use in an active pediatric interventional program in the United States. Study Design., This study is a retrospective review of all interventional cardiac procedures performed at our institution from July 1, 2005 to June 30, 2008. Diagnostic (noninterventional) catheterizations, myocardial biopsies, invasive electrophysiology studies, and studies involving investigational devices were excluded. Interventions performed were compared with the manufacturer's labeled indications for each device. Results., During this 3-year period, 473 patients (median age 4.1 years) underwent 595 transcatheter interventions. An approved device was utilized for an off-label application in 63% of patients, and in 50% of all interventions performed. The most frequent off-label procedures were stent implantations (99% off-label), balloon dilations (78% off-label), and coil embolizations (29% off-label). In contrast, the off-label use of septal and ductal occluders was relatively uncommon. Conclusions., In our routine (noninvestigational) practice of pediatric interventional cardiology, 63% of patients underwent procedures utilizing medical devices for off-label indications. These data underscore the need to enhance cardiac device review and approval processes in the United States to include pediatric applications. [source] Classification of Compression Bandages: Practical AspectsDERMATOLOGIC SURGERY, Issue 5 2008HUGO PARTSCH MD BACKGROUND Compression bandages appear to be simple medical devices. However, there is a lack of agreement over their classification and confusion over the use of important terms such as elastic, inelastic, and stiffness. OBJECTIVES The objectives were to propose terms to describe both simple and complex compression bandage systems and to offer classification based on in vivo measurements of subbandage pressure and stiffness. METHODS A consensus meeting of experts including members from medical professions and from companies producing compression products discussed a proposal that was sent out beforehand and agreed on by the authors after correction. RESULTS Pressure, layers, components, and elastic properties (P-LA-C-E) are the important characteristics of compression bandages. Based on simple in vivo measurements, pressure ranges and elastic properties of different bandage systems can be described. Descriptions of composite bandages should also report the number of layers of bandage material applied to the leg and the components that have been used to create the final bandage system. CONCLUSION Future descriptions of compression bandages should include the subbandage pressure range measured in the medial gaiter area, the number of layers, and a specification of the bandage components and of the elastic property (stiffness) of the final bandage. [source] Phase Reversion-Induced Nanograined/Ultrafine-Grained Structures in Austenitic Stainless Steel and their Significance in Modulating Cellular Response: Biochemical and Morphological Study with Fibroblasts,ADVANCED ENGINEERING MATERIALS, Issue 12 2009R. Devesh Kumar Misra Materials science, engineering, and biological sciences have been combined to improve the tissue compatibility of medical devices. In this regard, nano/ultrafine structuring of austenitic stainless steel obtained using an innovative approach of "phase-reversion" has been evaluated for modulation of cellular activity. The biochemical and morphology study with fibroblasts point toward the improvement of tissue compatibility on comparison with coarse-grained structures, strengthening the foundation of nanostructured materials for bio-medical applications. [source] Highly Porous Nano- and Microstructured Films Loaded with Bioactive Agents for Biomedical Applications: Structure,Release Profile EffectsADVANCED ENGINEERING MATERIALS, Issue 8 2009Adi Rachelson The current study focuses on the nanostructuring of our new drug-eluting porous films and its effect on the drug release profile of both hydrophilic and hydrophobic drugs. Nanostructuring was obtained using both the dispersion and the condensation methods of emulsion processing. These new highly porous nanostructured films can be used as basic elements of various drug-eluting medical devices. [source] Towards predictive modelling of the electrophysiology of the heartEXPERIMENTAL PHYSIOLOGY, Issue 5 2009Edward Vigmond The simulation of cardiac electrical function is an example of a successful integrative multiscale modelling approach that is directly relevant to human disease. Today we stand at the threshold of a new era, in which anatomically detailed, tomographically reconstructed models are being developed that integrate from the ion channel to the electromechanical interactions in the intact heart. Such models hold high promise for interpretation of clinical and physiological measurements, for improving the basic understanding of the mechanisms of dysfunction in disease, such as arrhythmias, myocardial ischaemia and heart failure, and for the development and performance optimization of medical devices. The goal of this article is to present an overview of current state-of-art advances towards predictive computational modelling of the heart as developed recently by the authors of this article. We first outline the methodology for constructing electrophysiological models of the heart. We then provide three examples that demonstrate the use of these models, focusing specifically on the mechanisms for arrhythmogenesis and defibrillation in the heart. These include: (1) uncovering the role of ventricular structure in defibrillation; (2) examining the contribution of Purkinje fibres to the failure of the shock; and (3) using magnetic resonance imaging reconstructed heart models to investigate the re-entrant circuits formed in the presence of an infarct scar. [source] Bio-inspired Photoelectric Conversion Based on Smart-Gating NanochannelsADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Liping Wen Abstract Inspired by the light-driven, cross-membrane proton pump of biological systems, a photoelectric conversion system based on a smart-gating, proton-driven nanochannel is constructed. In this system, solar energy is the only source of cross-membrane proton motive force that induces a diffusion potential and photocurrent flowing through the external circuit. Although the obtained photoelectric conversion performance is lower than that of conventional solid photovoltaic devices, it is believed that higher efficiencies can be generated by enhancing the protonation capacity of the photo-acid molecules, optimizing the membrane, and synthesizing high-performance photosensitive molecules. This type of facile and environmentally friendly photoelectric conversion has potential applications for future energy demands such as the production of power for in vivo medical devices. [source] Prevention and control of biofilm-based medical-device-related infectionsFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2010Iolanda Francolini Abstract Biofilms play a pivotal role in healthcare-associated infections, especially those related to the implant of medical devices, such as intravascular catheters, urinary catheters and orthopaedic implants. This paper reviews the most successful approaches for the control and prevention of these infections as well as promising perspectives for the development of novel devices refractory to microbial adhesion, colonization and biofilm formation. [source] Antioxidant Activity of Degradable Polymer Poly(trolox ester) to Suppress Oxidative Stress Injury in the CellsADVANCED FUNCTIONAL MATERIALS, Issue 1 2010Paritosh P. Wattamwar Abstract Oxidative stress is a pathological condition that has been implicated as a central player in a variety of diseases, including vascular and neurodegenerative diseases. More recently, oxidative stress has also been shown to be involved in the biological incompatibility of many materials, especially at the nanoscale. As such, there is a critical need for new biomaterials that can inhibit this response, improving the compatibility of medical devices. In this work, trolox, a synthetic antioxidant and water-soluble analogue of Vitamin E, is polymerized to form an oxidation active polymer as a new class of biomaterial. Synthesized poly(trolox ester) polymers were formulated into nanoparticles using a single emulsion technique, and their size was controlled by changing the polymer concentration in the organic solvent. Nanoparticle cytotoxicity, protective effects against cellular oxidative stress, and degradation kinetics were all evaluated. Poly(trolox ester) nanoparticles were found to have little to no cytotoxicity and were capable of suppressing cellular oxidative stress induced by cobalt nanoparticles. In vitro degradation studies of poly(trolox ester) nanoparticles indicate that the antioxidant activity of nanoparticles was derived from its enzymatic degradation to release active antioxidants. [source] Novel Brush Polymers with Phosphorylcholine Bristle Ends: Synthesis, Structure, Properties, and BiocompatibilityADVANCED FUNCTIONAL MATERIALS, Issue 10 2009Gahee Kim Abstract New brush polymers with various numbers of bristle ends incorporating phosphorylcholine (PC) moieties are synthesized. The polymers are thermally stable up to 175,°C and form good-quality films with conventional spin-, roll-, and dip-coating, and subsequent drying processes. Interestingly, all these brush polymers, as a PC-containing polymer, demonstrate a stable molecular multi-bilayer structure in thin films that arise due to the efficient self-assembly of the bristles for temperatures <55,°C and PC-rich surfaces, and therefore successfully mimic natural cell-membrane surfaces. These brush-polymer films exhibit excellent water wettability and water sorption whilst retaining the remarkable molecular multi-bilayer structure, and thus have hydrophilic surfaces. These novel multi-bilayer structured films repel fibrinogen molecules and platelets from their surfaces but also have bactericidal effects on bacteria. Moreover, the brush-polymer films are found to provide comfortable surface environments for the successful anchoring and growth of HEp-2 cells, and to exhibit excellent biocompatibility in mice. These newly developed brush polymers are suitable for use in biomedical applications including medical devices and biosensors that require biocompatibility and the reduced possibility of post-operative infection. [source] Synthesis 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] Electrogelation for Protein AdhesivesADVANCED MATERIALS, Issue 6 2010Gary G. Leisk Novel electrochemical behavior of silk protein to generate an adhesive electrogel is reported. The biomimetic system demonstrates reversible adhesive properties (see image) and functions on both hydrated and dry surfaces. Further, the system utilizes all-biocompatible components and functions in an all-aqueous process at ambient conditions. Potential applications in medical devices and in environmentally compatible material systems are described. [source] Human exposure to phthalates via consumer productsINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2006TED SCHETTLER Summary Phthalate exposures in the general population and in subpopulations are ubiquitous and widely variable. Many consumer products contain specific members of this family of chemicals, including building materials, household furnishings, clothing, cosmetics, pharmaceuticals, nutritional supplements, medical devices, dentures, children's toys, glow sticks, modelling clay, food packaging, automobiles, lubricants, waxes, cleaning materials and insecticides. Consumer products containing phthalates can result in human exposures through direct contact and use, indirectly through leaching into other products, or general environmental contamination. Historically, the diet has been considered the major source of phthalate exposure in the general population, but all sources, pathways, and their relative contributions to human exposures are not well understood. Medical devices containing di-(2-ethylhexyl) phthalate are a source of significant exposure in a susceptible subpopulation of individuals. Cosmetics, personal care products, pharmaceuticals, nutritional supplements, herbal remedies and insecticides, may result in significant but poorly quantified human exposures to dibutyl phthalate, diethyl phthalate, or dimethyl phthalate. Oven baking of polymer clays may cause short-term, high-level inhalation exposures to higher molecular weight phthalates. [source] Polymers Move in Response to LightADVANCED MATERIALS, Issue 11 2006Y. Jiang Abstract Significant advances have recently been made in the development of functional polymers that are able to undergo light-induced shape changes. The main challenge in the development of such polymer systems is the conversion of photoinduced effects at the molecular level to macroscopic movement of working pieces. This article highlights some selected polymer architectures and their tailored functionalization processes. Examples include the contraction and bending of azobenzene-containing liquid-crystal elastomers and volume changes in gels. We focus especially on light-induced shape-memory polymers. These materials can be deformed and temporarily fixed in a new shape. They only recover their original, permanent shape when irradiated with light of appropriate wavelengths. Using light as a trigger for the shape-memory effect will extend the applications of shape-memory polymers, especially in the field of medical devices where triggers other than heat are highly desirable. [source] Nickel hypersensitivity: a clinical review and call to actionINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2 2010Sarah E. Schram MD Nickel sensitivity is common and increasing in prevalence. This review discusses nickel sensitivity and its association with body piercing and other environmental factors, occupational relevance, and potential implications for implantable metal medical devices. In addition, current European legislation that limits the release of nickel from jewelry is highlighted and an argument for similar legislation elsewhere is presented. [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] | |||||||||||||||||||||||||||||||||||||||||||