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Medical Device Material Selection: Pros and Cons Medical Device Companies Need to Know
Material selection is one of the most challenging—and important—components of medical device development. No matter how strong a concept or dedicated a team, selecting the wrong material can jeopardize a device’s commercialization timeline and likelihood of regulatory approval. Fortunately, the Kapstone team of experts is well-versed in device material selection and manufacturing as well as the testing needed to go with it. Our mission is to inspire, equip, and guide our partners in bringing the highest quality medical devices to market, which includes the material safety and effectiveness.
Today, we’ll discuss the answers to some broad questions your company might have about medical device material selection and identify the pros and cons of working with different materials. If you have further questions, please don’t hesitate to get in touch with the Kapstone team.
Selecting Materials for Prototyping
What factors influence the selection of materials for prototyping?
Every prototyping process is unique and will require a tailored approach to material selection. Fundamentally, though, material selection for a prototype needs to support the purpose of that prototype—in other words, the outcome it’s looking to test. If the aim of a test is to determine whether a device will fit in a particular spot, substitute materials will likely work. As development progresses, however, it becomes more important to build and test with high-fidelity materials.
Many medical devices will need to be tested in practical environments like operating rooms, among other settings. In those environments, where devices will be subject to stringent cleaning requirements, it’s essential to select materials that can withstand them.
Looking more broadly, cost and timing also play a role in prototype material selection. Some materials (like custom machining) are much more expensive than others (like 3D printing), and some are much more difficult to source with limited notice. Kapstone can help your team take a pragmatic approach to material selection, leveraging our global network of suppliers to ensure that you have the right materials available when you need them.
Engineering for Human Factors
How does a human factor approach to engineering inform material selection?
Human factors engineering and testing are becoming increasingly important to global regulatory bodies—and increasingly central to the Kapstone offering. This approach accounts for a device’s practical use in the clinical, surgical, or patient setting, taking human behavior, plausible errors, and biological interactions into account. In essence, human factor engineering allows for the creation of products that are optimized for human use.
Material selection is a fundamental component of human factor engineering. How a device looks, feels, and operates, among other aesthetic and functional concerns, contributes to its ability to achieve an outcome for a patient or clinician. This is particularly true for devices that require sustained or frequent human interaction. For example: consider a device that someone needs to hold in their hand to administer treatment. Constructing that device from a slippery, heavy, or otherwise obtrusive material restricts the user’s ability to administer that treatment, and therefore curtails the product’s efficacy.
Though that example may seem rudimentary, its principle should be applied holistically. Just as prototype material selection needs to support the purpose of a particular test, device material selection needs to support the goals and abilities of that device’s user.
Selecting Materials for the Final Product
What factors influence the selection of materials for your final product?
There may be a variety of implications that factor into the decision, but generally two important aspects that need to be considered when selecting materials for a final medical device are: biocompatibility and strength.
Biocompatibility
Biocompatibility, as is evident in the term itself, refers to a material or device’s compatibility with the tissues of the body. The FDA and other regulatory bodies require different testing and documentation regimens for different types of devices, based on those devices’ contact with the body. A device that only comes into contact with the body’s surface tissue for a limited time is evaluated very differently than a permanent tissue implant—and regulatory agencies also account for all the in-between cases.
Whether a material is biocompatible depends on its prominence and concentration, how the device that contains it will ultimately be used, the duration of its use, and several other factors. Fundamentally, selecting for biocompatibility is a device-specific endeavor. Many base materials have established history for use in medical devices, but the ultimate manufacturing process factors into the device’s biocompatibility. One cannot assume that a stainless steel or resin referencing an appropriate standard makes it safe for use in a medical device; there may be other substances introduced in the manufacturing process. Learn more about assessing biocompatibility from Kapstone here.
Strength
Strength, in this context, refers to a device’s resilience and ability to perform its intended function. Plastics, for example, are often cheap and easy to produce—but may make very poor screws for a bone implant. Conversely, stainless steel, though literally strong, would make a surface implant unwieldy. Again, while these examples may seem simple, their general principles can be applied to even the most complex cases.
In General: Best Practices for Medical Device Material Selection
- Consider the materials used in your final product, but also in its manufacturing. Industrial contamination could impact biocompatibility, safety, and efficacy.
- Wherever possible, utilize materials designed and intended for medical devices.
- Begin to design and test for biocompatibility and strength as early as possible.
- Work with trusted suppliers.
- Account for common material allergies like nickel and latex.
Given that every medical device will have unique material needs, we have intentionally kept this guidance relatively general. Material selection will always depend on the needs of your company, device, and most importantly, the patients and clinicians you are working so hard to serve. If you have further questions, please don’t hesitate to get in touch with the Kapstone team. We’d be happy to lend our expertise and trusted network to your project.
