The potential of electron beam irradiation for simultaneous surface modification and bioresorption control of PLLA for medical device applications

Bioresorbable polymers have been widely investigated as materials exhibiting significant potential for successful application in the medical fields of bone fixation devices and drug delivery. Further to the ability to control degradation, surface engineering of polymers has been highlighted as a key method central to their development. Previous work has demonstrated the ability of electron beam (e-beam) technology to control the degradation profiles and bioresorption of a number of commercially relevant bioresorbable polymers (poly-l-lactic acid (PLLA), L-lactide/ DL-lactide co-polymer (PLDL) and poly(lactic-co-glycolic acid) (PLGA). This work investigates the further potential of e-beam technology to impart added biofunctionality through the manipulation of polymer (PLLA) surface properties. A Dynamatron Continuous DC e-beam unit (Synergy Health, UK), with beam energies of 0.5, 0.75, and 1.5 MeV, was used for the irradiation of PLLA samples with delivered surface doses of 150 or 500 kGy at each energy level. The chosen conditions reflect the need to achieve a specific surface modification for the control of surface degradation as demonstrated in previous work. Surface characterization was then performed using contact angle analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and atomic force microscopy.
Results demonstrated a significant increase in surface wettability post e-beam treatment. In correlation with this, XPS data showed the introduction of oxygen-containing functional groups to the surface of PLLA. Raman spectroscopy indicated chain scission in the near surface region of PLLA. E-beam irradiation did not seem to affect the surface roughness of PLLA as a direct consequence of the treatment. In conclusion electron beam surface modification has been found to modify both the surface-to-bulk bioresorption profile and the surface hydrophilicity. Both could provide benefits in relation to the performance of implantable medical devices.

Fibre laser joining of highly dissimilar materials: Commercially pure Ti and PET hybrid joint for medical device applications

Laser transmission joining (LTJ) is growing in importance, and has the potential to become a niche technique for the fabrication of hybrid plastic-metal joints for medical device applications. The possibility of directly joining plastics to metals by LTJ has been demonstrated by a number of recent studies. However, a reliable and quantitative method for defining the contact area between the plastic and metal, facilitating calculation of the mechanical shear stress of the hybrid joints, is still lacking. A new method, based on image analysis using ImageJ, is proposed here to quantify the contact area at the joint interface. The effect of discolouration on the mechanical performance of the hybrid joints is also reported for the first time. Biocompatible polyethylene terephthalate (PET) and commercially pure titanium (Ti) were selected as materials for laser joining using a 200 W CW fibre laser system. The effect of laser power, scanning speed and stand-off distance between the nozzle tip and top surface of the plastic were studied and analysed by Taguchi L9 orthogonal array and ANOVA respectively. The surface morphology, structure and elemental composition on the PET and Ti surfaces after shearing/peeling apart were characterized by SEM, EDX, XRD and XPS.

Laser-fabricated PET-Ti Hybrid Joints for Medical Device Applications

Currently, micro-joining of plastic parts to metal parts in medical devices is achieved by using medical adhesives, For example, pacemakers, defibrillators and neurological stimulators are designed using silicone adhesive to seal the joint between the polyurethane connector module and the titanium can [1]. Nevertheless, the use of adhesive is problematic because it requires a long time to cure and has high tendency to produce leachable products which might be harmful to the human body. An alternative for directly joining plastics to metal without adhesive is therefore required. Laser transmission joining (LTJ) is growing in importance, and has the potential to gain the niche in micro-fabrication of plastics-metal hybrid joints for medical device applications. The possibility of directly joining plastics to metal by LTJ technique have been demonstrated by a number of studies in recent literature [2]. The widely-accepted understanding of LTJ between plastics and metal is that generation and rapid expansion of micro-bubbles at the plastics-metal interface exert high local pressure to press the melted plastics towards the metal surface features during the laser processing [2]. This subsequently creates the plastics-metal hybrid joint by the mechanisms of mechanical interlocking as well as chemical and physical bonds between the plastics and metal surfaces. Although the micro-bubbles can help promote the mechanical interlocking effect to increase the joint strength, the creation of bubble is a random and complex process depending on the complicated interactions between the laser intensity, thermal degradation properties of plastics, surface temperature and topographical features of metal. In an ideal situation, it is desirable to create the hybrid plastics-metal joint without bubbles. However, the mechanical performance of the hybrid plastics-metal joint without bubbles is still unknown, and systematic comparison between the hybrid joints with and without bubbles is lacking in literature. This becomes the objective of this study. In this work, the laser process parameters were carefully chosen from a preliminary study, such that different hybrid joints: with and without bubbles can be produced and compared. Biocompatible PET and commercially pure Ti were selected as materials for laser joining.

La normativa tecnica sul software medical device: analisi del rischio ed impatto sulle aziende sanitarie

Quadro normativo sui Dispositivi Medici e la sua evoluzione (2007/47,UNI CEI EN ISO 14971). Software DM: processo di certificazione,gestione di reti IT medicali, ruoli e responsabilità (CEI 80001-1). Casi d'uso: Linee guida: MEDDEV e linee guida svedesi più relativi esempi applicabili alle aziende sanitarie.

Effects of congressional modernization laws on public access to innovative medical device technologies

The Federal Food and Drug Administration (FDA) and the Centers for Medicare and Medicaid (CMS) play key roles in making Class III, medical devices available to the public, and they are required by law to meet statutory deadlines for applications under review. Historically, both agencies have failed to meet their respective statutory requirements. Since these failures affect patient access and may adversely impact public health, Congress has enacted several “modernization” laws. However, the effectiveness of these modernization laws has not been adequately studied or established for Class III medical devices. ^ The aim of this research study was, therefore, to analyze how these modernization laws may have affected public access to medical devices. Two questions were addressed: (1) How have the FDA modernization laws affected the time to approval for medical device premarket approval applications (PMAs)? (2) How has the CMS modernization law affected the time to approval for national coverage decisions (NCDs)? The data for this research study were collected from publicly available databases for the period January 1, 1995, through December 31, 2008. These dates were selected to ensure that a sufficient period of time was captured to measure pre- and post-modernization effects on time to approval. All records containing original PMAs were obtained from the FDA database, and all records containing NCDs were obtained from the CMS database. Source documents, including FDA premarket approval letters and CMS national coverage decision memoranda, were reviewed to obtain additional data not found in the search results. Analyses were conducted to determine the effects of the pre- and post-modernization laws on time to approval. Secondary analyses of FDA subcategories were conducted to uncover any causal factors that might explain differences in time to approval and to compare with the primary trends. The primary analysis showed that the FDA modernization laws of 1997 and 2002 initially reduced PMA time to approval; after the 2002 modernization law, the time to approval began increasing and continued to increase through December 2008. The non-combined, subcategory approval trends were similar to the primary analysis trends. The combined, subcategory analysis showed no clear trends with the exception of non-implantable devices, for which time to approval trended down after 1997. The CMS modernization law of 2003 reduced NCD time to approval, a trend that continued through December 2008. This study also showed that approximately 86% of PMA devices do not receive NCDs. ^ As a result of this research study, recommendations are offered to help resolve statutory non-compliance and access issues, as follows: (1) Authorities should examine underlying causal factors for the observed trends; (2) Process improvements should be made to better coordinate FDA and CMS activities to include sharing data, reducing duplication, and establishing clear criteria for “safe and effective” and “reasonable and necessary”; (3) A common identifier should be established to allow tracking and trending of applications between FDA and CMS databases; (4) Statutory requirements may need to be revised; and (5) An investigation should be undertaken to determine why NCDs are not issued for the majority of PMAs. Any process improvements should be made without creating additional safety risks and adversely impacting public health. Finally, additional studies are needed to fully characterize and better understand the trends identified in this research study.^

Tools for compliance for the medical device and in vitrol diagnostic product industries.

Mode of access: Internet.

Medical device amendments of 1975 : hearings before the Subcommittee on Health and the Environment of the Committee on Interstate and Foreign Commerce, House of Representatives, Ninety-fourth Congress, first session, on H.R. 5545 ... H.R. 974 ... S. 510 ....

Hearings held July 28-31, 1975.

Indwelling catheters and medical implants with FXIIIa inhibitors:a novel approach to the treatment of catheter and medical device-related infections

Central venous catheters (CVCs) are being utilized with increasing frequency in intensive care and general medical wards. In spite of the extensive experience gained in their application, CVCs are related to the long-term risks of catheter sheath formation, infection, and thrombosis (of the catheter or vessel itself) during catheterization. Such CVC-related-complications are associated with increased morbidity, mortality, duration of hospitalization, and medical care cost [1]. The present study incorporates a novel group of Factor XIIIa (FXIIIa, plasma transglutaminase) inhibitors into a lubricious silicone elastomer in order to generate an optimized drug delivery system whereby a secondary sustained drug release profile occurs following an initial burst release for catheters and other medical devices. We propose that the incorporation of FXIIIa inhibitors into catheters, stents, and other medical implant devices would reduce the incidence of catheter sheath formation, thrombotic occlusion, and associated staphylococcal infection. This technique could be used as a local delivery system for extended release with an immediate onset of action for other poorly aqueous soluble compounds. © 2012 Elsevier B.V. All rights reserved.

Working with the public sector:SME medical device innovation and pre-procurement

Healthcare providers are under ever increasing pressure to deliver more technologically advanced care without increasing costs. Innovation is essential (Darzi, 2008), and for this healthcare providers rely on innovation within commercial companies. SMEs have an important part to play in this sector (NHS Supply Chain Parliamentary Brief, 2013). Collaboration between SME suppliers and the NHS for innovation forms the focus of this paper. We examine the academic literature on interorganizational innovation including academic insights from the areas of forward commitment procurement (Environmental Innovation Advisory Group, 2003-2008), pre-commercial procurement (Bos & Corvers, 2007), innovation and SMEs. We then explore practice, first from a policy and business sector perspective. Second, we present evidence from fifteen cases of interorganizational innovation projects involving SMEs and UK healthcare providers. Our findings show much effort is being put into creating opportunities for more interorganizational innovation of medical devices. Working across organizational boundaries presents added complexity to the innovation environment and process, and the challenge of developing high-quality cross-boundary group interaction.

Capturing User Requirements in Medical Device Development: The Role of Ergonomics

Measuring and fulfilling user requirements during medical device development will result in successful products that improve patient safety, improve device effectiveness and reduce product recalls and modifications. Medical device users are an extremely heterogeneous group and for any one device the users may include patients, their carers as well as various healthcare professionals. There are a number of factors that make capturing user requirements for medical device development challenging including the ethical and research governance involved with studying users as well as the inevitable time and financial constraints. Most ergonomics research methods have been developed in response to such practical constraints and a number of these have potential for medical device development. Some are suitable for specific points in the device cycle such as contextual inquiry and ethnography, others, such as usability tests and focus groups may be used throughout development. When designing user research there are a number of factors that may affect the quality of data collected including the sample of users studied, the use of proxies instead of real end-users and the context in which the research is performed. As different methods are effective in identifying different types of data, ideally more than one method should be used at each point in development, however financial and time factors may often constrain this.

Design-phase-specific selection of user research methods

For increasing the usability of a medical device the usability engineering standards IEC 60601-1-6 and IEC 62366 suggest incorporating user information in the design and development process. However, practice shows that integrating user information and the related investigation of users, called user research, is difficult in the field of medical devices. In particular, identifying the most appropriate user research methods is a difficult process. This difficulty results from the complexity of the medical device industry, especially with respect to regulations and standards, the characteristics of this market and the broad range of potential user research methods available from various research disciplines. Against this background, this study aimed at guiding designers and engineers in selecting effective user research methods according to their stage in the design process. Two approaches are described which reduce the complexity of method selection by summarizing the high number of methods into homogenous method classes. These approaches are closely connected to the medical device industry characteristic design phases and therefore provide the possibility of selecting design-phase- specific user research methods. In the first approach potential user research methods are classified after their characteristics in the design process. The second approach suggests a method summarization according to their similarity in the data collection techniques and provides an additional linkage to design phase characteristics. Both approaches have been tested in practice and the results show that both approaches facilitate user research method selection. © 2009 Springer-Verlag.