Components Of Medical Devices Research Articles

Albumin-derived perfluorodecalin-based hybrid systems with developed effective surfaces aimed at biomedical application

The study aims to approach a coating layer based on alginate functionalized with albumin nanocoated oxygenating factor, constituting a safe and even contact surface with epithelial cells in system components for medical devices to support maintaining the human lung cells’ function. The alginate coating layer with incorporated albumin-coated oxygenating element was designed (ALG_Alb-PFD). As an oxygenating factor, perfluorodecalin was applied at three saturation levels with oxygen: 0%, 21%, and 100%. The studies were performed on human adenocarcinoma A549 cell lines derived from human lung epithelial cells cultured in configuration with the designed coatings. Scanning electron microscopy, flow cytometry, and fluorescence microscopy were applied to evaluate cell function and the system morphology. AFM and SEM-EDX characterized the coating layer material. The designed coating ensured the viability of human lung cells cultured on the coating layer during 10 days of culture. An oxygenating factor presence was confirmed by SEM-EDX analysis of the ALG_Alb-PFD. However, no significant discrepancies were noted between the coatings with different saturation levels after 10 days of culture. Moreover, the AFM-analyzed profiles of the coating surface confirmed/indicated the formation of additional elements in the coating due to using an oxygenating element, which increases the effective contact area with cells. The platform based on alginate with the developed surface of contact of oxygenating factor incorporated within the coating layer ensures the sustained growth and morphology of the human lung cells, which can be considered a therapeutic element of system components of medical devices for maintaining human lung cells’ function.

Effect of Gamma and X-ray Irradiation on Polymers Commonly Used in Healthcare Products.

Synthetic organic polymers commonly are used in the construction of healthcare product and medical device components. Medical devices often are sterilized to ensure that they are free from viable microorganisms. A common technique to achieve this is using ionizing radiation, usually gamma. A trend exists in industrial sterilization to supplement gamma with alternative accelerator technologies (e.g., X-ray). In the current work, studies were performed to characterize polymer modifications caused by gamma and X-ray sterilization processes and to assess the comparative equivalency. The studies were developed to evaluate two key process parameters: dose and dose rate. Three commonly used polymers were selected: high-density polyethylene, low-density polyethylene, and polypropylene. Four grades of each family were chosen. The dose assessment involved sample exposures to both gamma and X-ray irradiation at two dose levels (30 and 55 kGy). All other processing conditions, including dose rate, were controlled at standard processing levels akin to each sterilization technology. The dose rate assessment expanded on each dose level by introducing two additional dose rate parameters. Subsequent laboratory testing used techniques to characterize physico-chemical properties of the polymers to ascertain equivalency across test groups. Initial results indicated positive levels of equivalency between gamma and X-ray irradiation.

Development of an Automatic Mobile Measurement Tester for Medical Device Power Supplies

The paper presents the process of constructing and programming an automatic measurement tester that can be operated remotely via the Internet. The proposed innovative tester can be used for rapid and automated verification of compliance of medical device components such as power supplies. The process of writing the program supporting the measurement tester is presented and the principle of its operation is described, along with the method of generating the developed measurement results.

Problematic aspects of customs regulation of imported components of medical devices

In modern conditions of sanctions policy, the issue of import of various categories of goods is subject to special control and attention from the state. This aspect may be due, on the one hand, to the introduction of retaliatory measures related to the prohibitions and restrictions imposed on the import of certain goods, and, on the other hand, to the development of a special approach to customs clearance of products, manifested in the simplification of requirements for the provision of accompanying documents. Of course, such a category of goods as medical devices, being the most important from the point of view of its intended purpose, requires close attention from the state, especially due to the fact that a significant amount of medical devices and their corresponding accessories are imported from third countries. The article discusses in detail the basic requirements for documents that must be accompanied by imported medical devices, examines the key aspects of customs clearance of this category of goods, and highlights problematic issues related to the import of medical device accessories, on the basis of which proposals were formulated for their settlement.

Design of Fine Life Cycle Prediction System for Failure of Medical Equipment

The inquiry process of traditional medical equipment maintenance management is complicated, which seriously affects the efficiency and accuracy of medical equipment maintenance management, and causes a lot of waste of manpower and materials. In order to accurately predict the failure of medical equipment, an accurate prediction system for failure life cycle of medical equipment was designed. The system is divided into four modules: the whole life cycle management module constructs the life cycle data set of medical devices from the three parts of the management in the early stage, the middle and the later stage; the status detection module monitors the main operation data of the medical device components through the normal value of the relevant sensitive data in the whole life cycle management module; the main function of the fault diagnosis module is based on the medical equipment whole life cycle management module. The operation data of equipment is diagnosed by inference machine; the fault prediction module builds a fine prediction system based on least square support vector machine algorithm, and uses AFS ABC algorithm to optimize the model to obtain the optimal model with the regularized parameters and width parameters, and the optimal model is used to predict the medical equipment failure. In order to verify the effectiveness of the design system, comparative experiments are designed to verify. The results show that the designed system can accurately predict the failure of electrocardiogram diagnostic instrument and incubator, and has high support and reliability. Compared with the comparison system, the prediction error of the design system is the smallest and the program running time is the shortest. Therefore, the design system can accurately predict the different failure types and causes of medical devices.

Thick Film PVD-Based Medical Device Components

Abstract Using a physical vapor deposition process to manufacture medical device components reduces post-processing time and improves materials properties. This article addresses metallic sputter deposition technologies for Nitinol medical devices.

Detection of acoustic emission from nanofiber nonwovens under tensile strain – An ultrasonic test setup for critical medical device components

In the biomedical field, nanofiber materials are gaining increasing application. For material characterization of nanofiber fabrics, tensile testing and scanning electron microscopy (SEM) are established standards. However, tensile tests provide information about the entire sample without information about single fibers. Conversely, SEM images examine individual fibers, but cover only a small section near the surface of the sample. To gain information on failure at the fiber level under tensile stress, recording of acoustic emission (AE) is a promising method, but challenging due to weak signal intensity. Using AE recording, beneficial findings can be obtained even on "invisible" material failure without affecting tensile tests. In this work, a technology for recording weak ultrasonic AE of tearing nanofiber nonwovens is presented, which uses a highly sensitive sensor. Functional proof of the method using biodegradable PLLA nonwoven fabrics is provided. The potential benefit is demonstrated by unmasking significant AE intensity in an almost imperceptible bend in the stress-strain curve of a nonwoven fabric. AE recording has not yet been performed on standard tensile tests of unembedded nanofiber material intended for safety-related medical applications. The technology has the potential to enrich the spectrum of testing methods, even those not confined to medical field.

4D prints of flexible dosage forms using thermoplastic polyurethane with hybrid shape memory effect

Thermoplastic polyurethanes are versatile materials due to their flexible and elastic properties. In research, medicine, and pharmacy, they are used in dosage forms, implants or as components of medical devices. To gain a deeper understanding of the influences on unfolding or expanding dosage forms, in this publication, 3D printing was used to produce differently shaped and foldable objects from various technical thermoplastic polyurethane filaments. The shape memory behaviour of the dosage forms was exploited to fold and package them in water-soluble hard gelatin capsules. The unfolding time and dimensional recovery of the 3D printed dosage forms were investigated as a function of material properties and shape. As an example, for the use of flexible dosage forms, 3D models have been designed so that their unfolded size is suitable for possible gastric retention. Depending on the shape and material, different unfolding behaviours could be shown. Over a storage period of 60 days, a time related stress on the 4D printed objects was evaluated, which possibly affects the unfolding process. The results of this work aim to be used to evaluate the behaviour of 3D printed unfolding and expanding dosage forms and how they may be suitable for the development of innovative sustained drug delivery concepts or medicinal devices. The basic principle of a hybrid shape memory effect used here could possibly be applied to other drug delivery strategies besides gastric retention.

March Medical Touts Better Way to Source Medical Device Components

March Medical Touts Better Way to Source Medical Device Components

Physicochemical, Bacteriostatic, and Biological Properties of Starch/Chitosan Polymer Composites Modified by Graphene Oxide, Designed as New Bionanomaterials.

The application of natural polymer matrices as medical device components or food packaging materials has gained a considerable popularity in recent years, this has occurred in response to the increasing plastic pollution hazard. Currently, constant progress is being made in designing two-component or three-component systems that combine natural materials which help to achieve a quality comparable to the purely synthetic counterparts. This study describes a green synthesis preparation of new bionanocomposites consisting of starch/chitosan/graphene oxide (GO), that possess improved biological activities; namely, good tolerability by human cells with concomitant antimicrobial activity. The structural and morphological properties of bionanocomposites were analyzed using the following techniques: dynamic light scattering, scanning and transmission electron microscopy, wettability and free surface energy determination, and Fourier transform infrared spectroscopy. The study confirmed the homogenous distribution of GO layers within the starch/chitosan matrix and their large particle size. The interactions among the components were stronger in thin films. Additionally, differential scanning calorimetry analysis, UV–vis spectroscopy, surface colour measurements, transparency, water content, solubility, and swelling degree of composites were also performed. The mechanical parameters, such as tensile strength and elongation at break (EAB) were measured in order to characterise the functional properties of obtained nanocomposites. The GO additive altered the thermal features of the composites and decreased their brightness. The EAB of composite was improved by the introduction of GO. Importantly, cell-based analyses revealed no toxic effect of the composites on HaCat keratinocytes and HepG2 hepatoma cells, although a pronounced bacteriostatic effect against various strains of pathogenic bacteria was observed. In conclusion, the starch/chitosan/GO nanocomposites reveal numerous useful physicochemical and biological features, which make them a promising alternative for purely synthetic materials.

A shelf-life study of silica- and carbon-based mesoporous materials

Mesoporous silica- and carbon-based materials, including bioactive glasses, have proven potential as components of medical devices and as drug carriers. From an application perspective, knowledge about the shelf-life stability of these materials under various conditions is vital. Here, mesoporous bioactive glasses (MBGs) synthesized by aerosol-assisted spray-drying and by a batch sol–gel method, mesoporous silicas of SBA-15 type, and mesoporous carbons CMK-1 and CMK-3 have been stored under varying conditions, e.g. at different temperature and relative humidity (RH), and in different storage vessels. The results show that the silica-based materials stored in Eppendorfs are sensitive to humidity. Spray dried MBGs decompose within 1 month at a RH >5%, whilst sol–gel MBGs are more stable up to a RH >60%. Changing the storage vessel to sealed glass flasks increases the MBGs lifetime significantly, with no degradation during 2 months of storage at a RH = 75%. SBA-15 stored in Eppendorfs are more stable compared to MBGs, and addition of F- ions added during the synthesis affects the material degradation rate. Mesoporous carbons are stable under all conditions for all time points. This systematic study clearly demonstrates the importance of storage conditions for mesoporous materials which is crucial knowledge for commercialization of these materials.

Temperature dependence of nickel ion release from nitinol medical devices.

Nitinol exhibits unique (thermo)mechanical properties that make it central to the design of many medical devices. However, nitinol nominally contains 50 atomic percent nickel, which if released in sufficient quantities, can lead to adverse health effects. While nickel release from nitinol devices is typically characterized using in vitro immersion tests, these evaluations require lengthy time periods. We have explored elevated temperature as a potential method to expedite this testing. Nickel release was characterized in nitinol materials with surface oxide thickness ranging from 12 to 1564 nm at four different temperatures from 310 to 360 K. We found that for three of the materials with relatively thin oxide layers, ≤ 87 nm nickel release exhibited Arrhenius behavior over the entire temperature range with activation energies of 80 to 85 kJ/mol. Conversely, the fourth ''black-oxide'' material, with a much thicker, complex oxide layer, was not well characterized by an Arrhenius relationship. Power law release profiles were observed in all four materials; however, the exponent from the thin oxide materials was approximately 1/4 compared with 3/4 for the black-oxide material. To illustrate the potential benefit of using elevated temperature to abbreviate nickel release testing, we demonstrated that a > 50 day 310 K release profile could be accurately recovered by testing for less than 1 week at 340 K. However, because the materials explored in this study were limited, additional testing and mechanistic insight are needed to establish a protective temperature scaling that can be applied to all nitinol medical device components.

Leveraging Extraction Testing to Predict Patient Exposure to Polymeric Medical Device Leachables Using Physics-based Models.

Toxicological risk assessment approaches are increasingly being used in lieu of animal testing to address toxicological concerns associated with release of chemical constituents from polymeric medical device components. These approaches currently rely on in vitro extraction testing in aggressive environments to estimate patient exposure to these constituents, but the clinical relevance of the test results is often ambiguous. Physics-based mass transport models can provide a framework to interpret extraction test results to provide more clinically relevant exposure estimates. However, the models require system-specific material properties, such as diffusion (D) and partition coefficients (K), to be established a priori for the extraction conditions. Using systems comprised high-density polyethylene and 4 different additives, we demonstrate that these properties can be quantified through standard extraction testing in hexane and isopropyl alcohol. The values of D and K derived in this manner were consistent with theoretical predictions for these quantities. Based on these results, we discuss both the challenges and benefits to leveraging extraction data to parameterize physics-based exposure models. Our observations suggest that clinically relevant, yet still conservative, exposure dose estimates provided by applying this approach to a single extraction measurement can be more than 100 times lower than would be measured under typical aggressive extraction conditions. However, to apply the framework on a routine basis, limiting values of D and K must be established for device-relevant systems either through the aggregation and analysis of more extensive extraction test data and/or advancements in theoretical and computational modeling efforts to predict these quantities.

Effect of coated and geometrically modified tools on performance of electrochemical micromachining

ABSTRACT Micro-holes are the basic features which are found in various components of medical devices, electronics, and biotechnology devices. The existing machining methods in ECMM for making micro-holes are generally accompanied with higher overcut (OC). Therefore, it is important to suppress OC and improve the machining rate (MR) which predominantly depend on electrode size, electrical parameters, tool electrode insulation, and electrolyte type. Hence, in this research, the suitable tool geometry and coating for the tool electrode is proposed, namely, ceramic, hot melt adhesive (HMA), and hollow wedge, short solid tools, respectively. The effect of electrolyte concentration in g/L, machining voltage in V and duty cycle in % on the OC and MR was studied. The results show that the ceramic tool produces 43.1% lesser OC than normal tool at the parameter combination of 23 g/L, 15 V, and 85% and short solid tool produces 74.3% higher MR for former with same parametric combination. The scanning electron microscope pictures of micro-holes were analyzed to study the effect of tool geometry and its coating. The ceramic and HMA coated tools control the leakages of current and shape modified tools to enhance the flow of current in the inter-electrode gap.

Antibody inhibition of contact factor XII reduces platelet deposition in a model of extracorporeal membrane oxygenator perfusion in nonhuman primates

BackgroundThe contact factor XII (FXII) activates upon contact with a variety of charged surfaces. Activated FXII (FXIIa) activates factor XI, which activates factor IX, resulting in thrombin generation, platelet activation, and fibrin formation. In both in vitro and in vivo rabbit models, components of medical devices, including extracorporeal oxygenators, are known to incite fibrin formation in a FXII‐dependent manner. Since FXII has no known role in hemostasis and its inhibition is therefore likely a safe antithrombotic approach, we investigated whether FXII inhibition also reduces accumulation of platelets in extracorporeal oxygenators. ObjectivesWe aimed to determine the effect of FXII inhibition on platelet deposition in perfused extracorporeal membrane oxygenators in nonhuman primates. MethodsA potent FXII neutralizing monoclonal antibody, 5C12, was administered intravenously to block contact activation in baboons. Extracorporeal membrane oxygenators were temporarily deployed into chronic arteriovenous access shunts. Radiolabeled platelet deposition in oxygenators was quantified in real time using gamma camera imaging. Biochemical assays were performed to characterize the method of action of 5C12. ResultsThe anti‐FXII monoclonal antibody 5C12 recognized both the alpha and beta forms of human and baboon FXII by binding to the protease‐containing domain, and inhibited FXIIa activity. Administration of 5C12 to baboons reduced platelet deposition and fibrin formation in the extracorporeal membrane oxygenators, in both the presence and absence of systemic low‐dose unfractionated heparin. The antiplatelet dose of 5C12 did not cause measurable increases in template bleeding times in baboons. ConclusionsFXII represents a possible therapeutic and safe target for reducing platelet deposition and fibrin formation during medical interventions including extracorporeal membrane oxygenation.

Collodion Remover Can Degrade Plastic-Containing Medical Devices Commonly Used in the Intensive Care Unit

ABSTRACTCollodion remover, a solvent blend used to remove collodion glue after long-term video EEG monitoring, was implicated as a potential causative factor in patient safety events at our institution during which damage to plastic components of medical devices was noted in the intensive care unit. We sought to determine experimentally whether collodion remover could lead to degradation of multiple plastic-containing medical devices commonly used in the intensive care unit to determine whether workflow changes were needed during electrode removal. We exposed devices to collodion remover for brief, intermediate, and prolonged durations. We report that collodion remover is capable of degrading the hard plastic components of multiple medical devices after prolonged exposure; however, intermediate duration exposure was also capable of producing damage to clave connectors used with intravenous and central lines, which could plausibly lead to adverse events given the widespread use of these devices. These data suggest a pathway-based approach to collodion remover use might be beneficial in minimizing the potential impact of this solvent on plastic-containing medical devices.

High dimensional variable selection with clustered data: an application of random multivariate survival forests for detection of outlier medical device components

ABSTRACTIn many medical studies patients are nested or clustered within doctor. With many explanatory variables, variable selection with clustered data can be challenging. We propose a method for variable selection based on random forest that addresses clustered data through stratified binary splits. Our motivating example involves the detection orthopedic device components from a large pool of candidates, where each patient belongs to a surgeon. Simulations compare the performance of survival forests grown using the stratified logrank statistic to conventional and robust logrank statistics, as well as a method to select variables using a threshold value based on a variable's empirical null distribution. The stratified logrank test performs superior to conventional and robust methods when data are generated to have cluster-specific effects, and when cluster sizes are sufficiently large, perform comparably to the splitting alternatives in the absence of cluster-specific effects. Thresholding was effective at distinguishing between important and unimportant variables.

Optimal Design of Sandwich Composite Cradle for Computed Tomography Instrument by Analyzing the Structural Performance and X-ray Transmission Rate.

Carbon fiber-reinforced composite has an excellent X-ray transmission rate as well as specific modulus and strength. The major components of medical devices, X-ray systems, and computed tomography (CT) equipment that require superior X-ray transmission performance also require structural performance for deformation. Therefore, medical components consist of a sandwich composite structure with carbon fiber composites applied as a face material. The X-ray transmission ratios of face material and foam material were measured according to thickness, and the relation equation for thickness and X-ray transmission rate was derived. The X-ray transmission rate for the sandwich composite structure consisting of face and core material was measured and the relationship between the X-ray transmission rate and the dimension for thickness of sandwich cradle was derived. Using the optimization process, the thicknesses of face and core materials for sandwich cradles were determined to minimize the cost of used materials. They also met the criteria that the deflection should not be more than 20 mm, and the X-ray transmission rate of the cradle should be equal to or greater than that of aluminum at 1.5 mm thickness. The sequence pattern of face material was proposed through structural analysis. The face material of the sandwich cradle was manufactured by a resin infusion and vacuum bagging method, followed by inserting the core between the cured faces. Next, the sandwich cradle assembly was completed and re-cured. The sandwich cradle met the criteria that the deflection at the end was 19.04 mm and the X-ray transmission was 78.7% greater than the X-ray transmission of 1.5 mm aluminum.

Compilation of International Standards and Regulatory Guidance Documents for Evaluation of Biomaterials, Medical Devices, and 3-D Printed and Regenerative Medicine Products

The development of biomaterials, medical device components, finished medical products, and 3-D printed and regenerative medicine products is governed by a variety of international and country-specific standards and guidelines. Of greatest importance to planning, executing, and reporting biocompatibility, safety and efficacy studies for most biomaterials and medical components or products are the International Organization for Standardization guidelines, U.S. Pharmacopeial Convention, ASTM International, and Conformité Européenne (European Conformity) marking. The International Medical Device Regulators Forum publishes harmonized standards similar to the International Council for Harmonization. Good Laboratory Practices are applicable and guidance documents for the development of drugs and biologics can also be relevant to biomaterials, medical device components, and medical products and more recently to products produced by 3-D printing or additive manufacturing. Regenerative products may have medical device-based scaffolding and may be treated as biologics, reflecting the cell and tissue components. This compilation of international standards and guidelines provides toxicologic pathologists, toxicologists, bioengineers, and allied professionals with an overview of and source for important regulatory documents that may apply to the nonclinical development of their products.

Improved covalent immobilization of lysozyme on silicone rubber-films grafted with poly(ethylene glycol dimethacrylate-co-glycidylmethacrylate)

Silicone rubber (SR) is widely used in medical and food sectors due to its excellent mechanical properties. Either as component of medical devices or surfaces in contact with food, there is a current demand to endow SR with antimicrobial activity. Although promising, covalent immobilization of lysozyme on SR is not an easy task and the yield of current approaches should be improved in terms of both amount and stability of the enzyme. The goal of this work was to implement an optimized approach to immobilize lysozyme through the formation of multiple bonds on SR-films. The SR-films were first grafted with poly(ethylene glycol dimethacrylate-co-glycidylmethacrylate), poly(EGDMA-co-GMA), by gamma-rays radiation and then chemically modified to provide them with a formyl group, which was later used to immobilize lysozyme. Two synthetic routes were investigated. Properties of grafted SR-films with immobilized lysozyme were characterized by means of attenuated total reflection infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and viscoelasticity. The enzymatic activity of the immobilized lysozyme on the grafted SR-films was studied by following the decrease in absorbance at 450nm using a suspension of lyophilized Micrococcus lysodeikticus. The enzymatic activity of immobilized lysozyme was tested covering a wide range of pH values and temperatures as well as under reuse cycles. The results show that immobilized lysozyme maintains good activity in the 6–11pH range and withstands several reuse cycles.