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Reliability of biomedical devices (REMED)

Objective

Specific Objectives

Subproject 1: Functional Materials and Surfaces
Research on innovative surface engineering processes and surface analysis
- to control the biochemical interaction of materials with living tissue and
- to measure potential risks associated to surface contamination coming from industrial processes.
The activities will focus on characterisation of surfaces and control of biomaterials interfaces.

Subproject 2: Performance Testing
- To conduct research in order to support the harmonisation of test methodologies for medical devices under clinically relevant conditions in support of Directive 93/42/EEC and related directives (e.g. 94/27/EC and 99/45/EC);
- To develop testing methods and qualification procedures for the monitoring of emission of health-unfriendly chemical compounds during production and/or us of medical devices and consumer products;
- To support the harmonisation of European databases on implant reliability.
Planned Deliverables

The project will contribute to codes and standards to implement the Directives 93/42EEC and 90/385/EEC. In addition, it is highly relevant for the JRC alert function to the policy makers.

As a result of the research:
- Guidelines for improvement of reliability and safety of biomedical devices;
- European networks;
- Workshops;
- Patents;
- Reports and journal publication;
- Testing techniques and facilities.

This will be achieved in the framework of European networks involving experts from industries, standardisation bodies, hospitals and research institutes.

Summary of deliverables made by: 31/12/2001
Subproject 1: Functional Materials and Surfaces

WP1 Deposition of carbon thin films - improvement of biocompatibility of medical devices: Carbon thin films have been deposited with a Microwave Assisted PVD reactor. The reactor has been intensively tested and carbon films with a controllable diamond character have been deposited. Influence of parameter deposition on films properties have been evaluated. Samples will be given to the PROTEC sector for wear tests;

WP2 Bio ceramic thin films - development of osteoinductive ceramics:. Results have demonstrated the clear osteoinductive property of the nacre before spraying and the partial remaining of the properties after spraying. The clear advantage of the coatings over pure Titanium opens a new route of development for biocompatible coatings. WP2 has been completed according to initial schedule and will not be pursued due to lack of staff;

WP3 Surface functionalisation: A biocompatible surface can be obtained by covalent immobilisation of proteins on the medical devices. One method is to graft aldehyde, carboxylic or epoxy moieties on the surface and to covalently bond the antibodies through their amine functions. We have deposited a functional film by plasma polymerisation of acrylic acid vapour using an inductive plasma source. Results show that acrylic functionalities can be maintained during deposition and a thin film of 200 to 1000 nm can be deposited with strong carboxylic character. The programme continues with deposition of Polyethylene Oxide (PeO) like films, but has been reduced due to lack of staff.

Another aspect of the work was the development of a plasma source configuration for treatment of catheters, in which a Transverse Flux plasma source has been tested and patented (JRC Innovation Award 2000). The programme has been interrupted due to lack of staff and will be resumed end of 2001.

Principal achievements: 1 patent granted (Inductively coupled Plasma source with internal Faraday cage), 1 SCA project in cooperation with FPU accepted; 1 NATO linkage grant accepted in collaboration with Russia, 1 Thematic Network on Plasma technologies for Food, Health and Environment accepted, 1 Research contract accepted within SCA project Nanomag.

Subproject 2: Performance Testing

As a follow-up of the suggestions of the 1999 Audit Report to establish together with ECVAM a key reference and consulting body for European biomaterials testing, the collaboration with ECVAM was further intensified. In particular a joint proposal for a Marie Curie Training Site "Research training in biomaterials testing using radiotracers" BIORAD was accepted. An analysis for joint clean room laboratories in the cyclotron-controlled area was made and pending budget allocation will be realised in the first half of 2002. Ongoing joint projects concern the health effects of wear debris (WP1) and metal compounds (WP2).

WP1 Wear Release Methodologies for Orthopedic Implants: A 12-station screening wear test facility based on a novel design was constructed and became operational in 2001. With this three different types of multi-directional screening wear test facilities are available to develop new screening wear test methods e.g. to replace the abandoned ASTM F732 standard for evaluating medical grade polyethylene. Research was dedicated in large part to cross-linked polyethylene also considering the oxidation during storage and long-term clinical use. Thin Layer Activation (TLA) for very sensitive wear monitoring of polymers (as suggested in ISO TR9326) was used for the first time on cross-linked polyethylene. The method proved its high sensitivity and accuracy compared to conventional techniques. Experimental procedures to study the clinical problem of spallation of wear resistant films and coatings were analysed. This action is further exploited in the frame of SCAs and is related to Subproject 1. To assess the cellular response of wear debris, procedures for isolation of wear particles from biological solutions after testing were further developed in collaboration with ECVAM. A further action to test these particles for their long-term health effects is going on with ECVAM;

WP2 Advanced Release Testing Methods for Medical Devices: This activity is linked to related ECVAM activities. It is relevant not only for Medical Device Directive, but also for the Directive 94/27/EC and the new Preparations Directive 99/45/EC. Material release from orthodontic materials is a point of increasing concern. The situation is rather complex in view of the wide range of materials being used in orthodontic applications; the varying clinical conditions during use and the absence of reference test procedures. The activity on the release of dental systems concerned in particular the use of different test conditions, such as test solutions. The use of radiotracers in these studies proved to be very useful, e.g. indicating the temporal instability of various solutions during long-term testing. The use of different components in a single implant may influence local release rates, which were measured by use of radiotracers. The concept was proven. The effect of proteins on the release of implants is also being undertaken in support of an improvement of ISO 10993 (Biological evaluation of medical devices) part 15;

WP3 Databases and Implant Registers: This work package was included in 2001 in view of a growing interest at a European level to set up databases on medical devices and adverse reactions. Various meetings were held with DG SANCO and a proposal for concerted action on adverse reactions to dental materials was proposed.

Output Indicators and Impact

DG contacts (meetings, reports, joint actions)
-Collaboration contracts, networks, SCAs;
-Publications, technical notes, patents reviews;
-Technical achievements;
-Students, scientific visitors, invited seminars.
Summary of the project

The REMED project aims at improving the reliability and safety of biomedical devices in support of EU-policies and the implementation and conception of the following directives:
1) Medical Device Directive 93/42/EEC;
2) New Preparations Directive 99/45/EC;
3) Nickel directive 94/27/EC.

The project addresses the two predominant problems in the application of implants: biocompatibility and long-term reliability. Increased biocompatibility can be obtained by modifying the implants surface biochemistry in such a way that the human body identifies the implanted surface as endogenous. This research is necessary for the selection of fabrication procedures and quality control to ensure optimum acceptance of the implants by the patients and reduction of social and medical costs. Better long-term reliability of implants requires the improvement of existing standards at the European level and the development and validation of testing methods to assess the material and device performance in order to guarantee the safe use and the functionality of the devices to the patient.

The project is subdivided into two sub-projects:
1) functional materials and surfaces;
2) performance testing.

The research activities focus on the principal objectives:
- to perform research in biomedical materials and devices in order to improve their biocompatibility and reliability for use in the human body;
- to develop and validate methods for the characterisation of biomaterials and performance testing of biomedical implants and prostheses;
- to establish and harmonize registers and databases for implants.

Rationale

Ageing of population and increased wealth lead to a steady increase in the use of biomedical components. The failure of prostheses or implanted medical systems in general may expose patients to life-threatening conditions and replacement of implants may cause serious problems. The increasing complexity of biomaterials and devices makes very difficult in the assessment of their reliability and lifetime under the severe service conditions associated with their use.
Standardisation requires the validation and harmonisation of testing and characterisation methods for a wide range of medical devices and the materials of which they are made. A wide range of characterisation and testing methods, which are needed for the project are available at the JRC in combination with expertise in reliability and lifetime assessment.

Funding Scheme

JRC - Joint Research Centre research

Coordinator

Institute for Health and Consumer Protection
Address

Ispra
Italy