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Conducting Biocompatibility Testing for a Medical Device

Interview with Jeff Geesin, Research Director & Medical Device Consultant

About Jeff Geesin

Jeff Geesin is a biochemist with extensive experience in corporate research and technical expertise in extracellular matrix biology, wound repair and regeneration, tissue engineering/regenerative medicine, and preclinical models of disease for testing therapeutic approaches. He managed project and career development activities for up to 30 technical staff with budget responsibilities up to $15 million, and projects to clinical stage for device and drugs in numerous therapeutic areas including orthopedics, dermal wound repair, women's health and urology, neurology, dermatology, and cardiovascular. Jeff currently works as an independent consultant, providing preclinical strategy development, biology/mechanism of action writing and strategy for planning for regulatory submissions, due diligence of products or technologies, and patent portfolio assessments and strategies. For more information, visit or

1. What is biocompatibility and how would one test a medical device for biocompatibility?

Biocompatibility refers to assessing the contact between components of a medical device and the body; it is the capability of a device to exist in harmony with surrounding tissues without causing unacceptable adverse effects. A device must perform its intended function without eliciting any undesirable local or systemic effects (for example, that it elicits little or no immune response in a given organism, or is able to integrate with a particular cell type or tissue), in the recipient or beneficiary of that technology. Biocompatibility measures aim to ensure the most appropriate beneficial cellular or tissue response in order to optimize the clinically relevant performance of a technology or device. When it comes to a medical device, assessing the local response to the device would generally require a simple implantation study. Complications can arise when the implant cannot be implanted in animals at a similar location than that intended in man. In such situations, best attempts to duplicate the intended use should be employed and a justification for why these adjustments were necessary should be drafted.

2. How would one determine what types of tests need to be conducted on their medical device?

The FDA has established classifications for approximately 1,700 different generic types of devices and grouped them into 16 medical specialties referred to as panels. Each of these generic types of devices is assigned to one of three regulatory classes based on the level of control necessary to assure the safety and effectiveness of the device. The three classes and the requirements which apply to them are: Class I General Controls, Class II General Controls and Special Controls, and Class III General Controls and Premarket Approval. Class I devices are subject to the least regulatory control, while Class II devices are those for which general controls alone are insufficient to assure safety and effectiveness, and existing methods are available to provide such assurances. In addition to complying with general controls, Class II devices are also subject to special controls. A Class III device is one for which insufficient information exists to assure safety and effectiveness solely through the general or special controls sufficient for Class I or Class II devices. Such a device needs premarket approval, a scientific review to ensure the device's safety and effectiveness, in addition to the general controls of Class I. Class III devices are usually those that support or sustain human life, are of substantial importance in preventing impairment of human health, or which present a potential, unreasonable risk of illness or injury.

3. Can you highlight some of the pitfalls in developing new materials and evaluating them for biocompatibility?

To promote more rapid development, it may be more strategic to choose a device material that already has data behind it. People often develop new materials for their device and, with the way the regulatory process is changing, running safety studies to test a new material would add additional delays and expense. A new device material can be a hard sell without proof of any dramatic improvements or benefits over existing technology. I believe that it's wiser in developing new materials to focus on big innovation with real strategic commercial advantage, rather than small changes to existing technology.

4. How would you help a device client who is looking to establish pre-clinical plans, including biocompatibility testing?

I help my clients in a few key areas: I can help them to look at and or develop their strategy, identify needs in the marketplace, and ascertain where technologies would be of best use. I occasionally get involved in assisting with research proposals to help obtain funding, as well as working to identify the required testing and supplier(s) best suited to perform efficacy and safety studies. I can also assist with writing for FDA submissions related to mechanisms of action and biology components. I can also be of help in developing intellectual property strategies to protect investment.

5. What are your thoughts on technical strategies for meeting FDA requirements?

It's important to develop a pre-clinical plan to address at risk issues and potential adverse effects to apply to your clinical plan. I have encountered situations in which a device material hasn't been characterized in depth before the biocompatibility studies are carried out. The FDA requires complete characterization, and if they don't see sufficient data to support this they would require the device maker to re-do its animal studies. I have encountered some device makers who haven't looked at cytotoxicity (for example, assessing problems related to local necrosis) prior to performing animal studies; I recommend running a cytotoxicity study first, to save the wasted time of having to run additional animal studies. I have also seen cases where the implant isn't properly fixed in the implanted animal which makes assessing tissue interaction difficult. Sometimes, samples are not properly trimmed or oriented when imbedded when they are sent for Pathological analysis which makes taking proper measurements difficult. It is also important to ensure sterility before the implantation study, as this can cause confounded tissue responses. When the selection has been narrowed down to a few device prototypes, it would be wise to go ahead and initiate the study as soon as possible, including the most promising candidates. The FDA is asking for human safety trials for almost everything and it's important to be aggressive with your timelines where possible. Streamlining the manufacturing process of your device from the beginning is crucial; if changes are needed after you've initiated your safety studies, you will be required to re-do your studies and you'll be required to re-run your studies with implants produced with your final manufacturing process.

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