By Sean Fenske, Editor-in-Chief

It all starts with the material (well, after the idea anyway). Material selection for a medical device project can be a significant factor in its success or failure. Realizing you’ve made the wrong choice later in the development process can add significant time and costs. On the other hand, leveraging the inherent advantages of a material can result in additional benefits with the finished devices that weren’t even imagined at the start.

Fortunately, there are partners who have extensive experience with a variety of materials. Working with them early in the process can help optimize selection of the right material for a specific application. They can share application knowledge and manufacturing expertise to support an OEM with material selection and polymer formulation for a medical device application. In addition, they can provide feedback on specifications and factors such as processability, biocompatibility, and sterilization.

Recently, two companies have been brought together under the DuPont umbrella, providing complementary expertise, offerings, and capabilities. In the following Q&A, two experts share valuable consultation on high-temperature, high-performance materials, such as PEEK. Raghu Vadlamudi, Chief Research and Technology Director for Donatelle, A DuPont Business (acquired in 2024), and Angela Hu, Senior Engineering Manager at Spectrum Plastics Group, A DuPont Business (acquired in 2023), explain when, where, and why to use PEEK for a medical device project.

Sean Fenske: What is PEEK? What are the properties that make it attractive to medical device manufacturers?

Angela Hu: Polyetheretherketone (PEEK) is a high-performance thermoplastic polymer utilized for many industries with critical performance requirements, such as aerospace, automotive, and medical. PEEK is known for its strong balance of engineering properties with high strength, high stiffness, wear resistance, and chemical resistance across a wide temperature range. Additionally, PEEK’s biocompatibility, radiolucency, and melt processability have made it an excellent material of choice for medical device manufacturers that may be looking for versatile engineering properties or for lightweight alternatives to metal.

Raghu Vadlamudi: Additionally, PEEK is biocompatible and meets ISO 10993 and USP Class VI standards, enabling its use in both short- and long-term implantable medical devices. Its radiolucency allows for clear imaging during X-rays and CT scans, as it does not interfere with diagnostic imaging like metallic implants do. Manufacturers can tailor its properties by using carbon or glass fiber-reinforced grades to enhance wear resistance or mechanical strength for specific applications.

Medical device manufacturers favor PEEK as a metal replacement in applications where weight, MRI compatibility, or reactions to metals such as nickel are concerns. It is versatile in manufacturing and can be machined, injection molded, or extruded to produce high-precision parts with complex geometries. With a well-established track record of FDA-cleared devices and long-term stability inside the human body, PEEK is increasingly used in spinal cages, orthopedic anchors, dental implants, and cardiovascular components. These attributes make PEEK an ideal choice for advanced, high-performance medical devices.

Fenske: When molded, what are the specific advantages compared to other materials?

Vadlamudi: PEEK provides better sterilization resistance than many other moldable materials. It withstands gamma irradiation without much property loss or discoloration, making it ideal for implantable devices.

Additionally, PEEK molds very well into complex, thin-walled geometries, allowing for high-precision manufacturing of intricate medical components. Molding of PEEK reduces the need for secondary machining, thereby lowering manufacturing costs and improving throughput.

When compared to metals like titanium or stainless steel, molded PEEK parts are lighter, non-conductive, radiolucent, and MRI-compatible, which provides clinical advantages in patient imaging and device tracking. This combination of performance, processability, and biocompatibility gives molded PEEK a unique position among high-performance materials in the medical device industry.

Hu: As Raghu mentioned, PEEK’s excellent chemical and hydrolysis resistance helps it maintain integrity through sterilization methods involving steam, gamma irradiation, or ethylene oxide gas. Also, PEEK has good flow characteristics, which allows for molding complex and precise features with excellent strength at thin-wall sections. PEEK also machines well for any applications that may require post-molding processes, which offers advantages for design flexibility on intricate designs.

Fenske: Given the miniaturization trend across healthcare, can you speak to the size of the molded components when using PEEK? How small can you go?

Hu: PEEK is a good candidate for small molding components and certainly has the melt processability to achieve micromolding features with tight tolerances. For manufacturability purposes, part design and aspect ratio are important considerations when working with thin-wall sections. Tool design and tool building are critical to achieve micron-level features and to ensure proper fit-up with careful consideration of the thermal expansion of tool steel at the elevated mold temperatures required to process parts. The small components that Spectrum has made have been in the range of 0.004 to 0.05 grams, with features as small as 200 microns.

Flow of any filled grades of PEEK with carbon or glass fiber should be carefully considered for manufacturability to achieve micromolding features. Part design considerations should be made if the diameter of the fibers in the filler is close to the target part design wall thicknesses to ensure proper flow within the tool, as well as promoting uniform distribution of filler fibers.

Vadlamudi: I agree with Angela. PEEK is exceptionally well-suited for miniaturized components in healthcare, and it has become a material of choice for micro-scale molded parts due to its ability to retain mechanical strength, chemical resistance, and dimensional stability even at very small sizes.

Using micro injection molding technology, PEEK components can be molded with feature sizes as small as tens of microns—in some cases, even below 50 microns, depending on the part design and mold quality. Donatelle currently has a part in production with a wall thickness of 37 microns. It’s possible to mold parts weighing less than 0.0001 grams, with extremely tight tolerances—often within a few microns—critical for applications like implantable anchors, surgical clips, microfluidic components, and endoscopic instrument tips.

The flow characteristics of PEEK, especially when processed correctly, allow it to fill very fine cavities in precision molds. Fillers such as carbon or glass fiber can also be incorporated at the micro-scale, though they may require more careful mold design due to reduced flow in tight geometries.

Molding extremely small PEEK parts requires specialized equipment, including:

• High-precision micro injection molding machines with low shot volumes and fine control
• Advanced mold tooling with micron-level cavity detail, often manufactured using EDM or laser micromachining
• Sophisticated metrology, such as CT scanning or optical profilers, for in-process and final inspection

In short, PEEK can be used to produce ultra-small components with high feature fidelity, making it ideal for the miniaturization trend taking place with medical devices. It supports innovation in areas like implantable drug delivery systems, neurostimulators, microcatheters, and other minimally invasive technologies where performance in confined geometries is critical.

Fenske: What medical device applications are typically leveraging PEEK? Why?

Vadlamudi: PEEK is widely leveraged in a broad range of medical device applications, especially in areas requiring high mechanical strength, chemical resistance, biocompatibility, and sterilization durability. Its unique material properties make it a preferred alternative to metals and other polymers in both implantable and non-implantable medical devices. Spinal implants, orthopedic implants, surgical instruments, and neurostimulation devices are just some medical device examples that use PEEK.

Hu: I agree. PEEK has had a long history of use in medical applications such as spinal fusion cages, orthopedic screws, drug delivery devices, and dental implants. PEEK continues to be one of the top choices among materials due to its good balance of engineering properties that can serve many medtech applications. PEEK continues to be a good option for a polymer-based solution for metal alternatives.

Fenske: Do you have any additional comments you’d like to share based on any of the topics we discussed or something you’d like to tell medical device manufacturers?

Hu: It’s an exciting time to be a part of DuPont! We’re innovating, advancing, and growing in healthcare. Our offerings bring together multiple businesses and span the entire healthcare value stream, making us an even more capable partner of choice in healthcare.

Vadlamudi: Together, we’re the global partner of choice for the world’s top healthcare companies, helping customers advance critical healthcare solutions and solve complex challenges with technical expertise and innovation.

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