Guidance on determining health effect of nanomaterials in medical devices

The European Commission Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) is in the process of finalizing a guidance document to help company to address the use of nanomaterials in medical devices and provides information for risk assessors regarding specific aspects that need to be considered in the safety evaluation of nanomaterials. The document was subject to a public consultation that ended on the 3rd of October.

The use of nanomaterials in medical devices can vary considerably. Examples are the use of free nanomaterials being a medical device and administered to the patient as such (e.g. iron oxide or gold nanomaterials for heat therapy against cancer), free nanomaterials in a paste-like formulation (e.g dental filling composites), free nanomaterials added to a medical device (e.g nanosilver as antibacterial agent in wound dressings), fixed nanomaterials forming a coating on implants to increase biocompatibility (e.g. nano-hydroxyapatite) or to prevent infection (e.g. nano-silver), or embedded nanomaterials to strengthen biomaterials (e.g. carbon nanotubes in a catheter wall).

This Guidance is aimed at providing information to help with safety evaluation and risk assessment on the use of nanomaterials in medical devices that should be considered in conjunction with the ISO 10993-1:2009 standard. The Guidance highlights the need for special considerations in relation to the safety evaluation of nanomaterials, in view of the possible distinct properties, interactions, and/or effects that may differ from conventional forms of the same materials.

For the risk evaluation of the use of nanomaterials in medical devices, a phased approach is recommended based on potential release and characteristics of the nanomaterials.

Non-invasive medical devices containing nanomaterials, with the exception of local reactions at the site of contact, do not in most instances pose an additional risk compared to non-invasive medical devices not containing nanomaterials and may be evaluated using the same methodology.

For invasive medical devices containing nanomaterials, including surface contacting devices in contact with breached skin or mucosa, the same principles for toxicity testing apply as for medical devices not containing nanomaterials. However, the biological effects of nanoparticles that are introduced or formed should be investigated both for local effects at the site of application and at possible distribution organs after migration, especially draining lymph nodes. In the safety evaluation, itself the potential release, accumulation, and persistence of the nanomaterials in the tissues is of utmost importance for the need of further testing. In this context, the possible dissolution/degradation of the nanomaterials also needs to be considered.

All safety evaluations should consider the potential specific physical-chemical properties of these nanomaterials, especially those medical devices that consist of free nanomaterials. The biological effects of nano-particles that are introduced should be investigated both at the site of deposition and at possible target organs for migration, especially draining lymph nodes.