Materials science evolves within a dynamic space, and this is especially true of medical materials, where research is taking this evolution to a whole new level. Advances in medical device design and manufacturing inadvertently have been the driving factor. A case in point is the introduction of 3D and now 4D printing, as well as the boom in digital patient care, all of which have opened the door to innovation in medical materials.

This new focus has paved the way for aggressive material development activities that I find very stimulating. For example, until fairly recently material selection for any manufacturing project, including medical device fabrication, revolved around the mechanical properties of the material. Engineering databases and material characterization property data sources, such as mold flow and NX software, were based entirely on industrial-grade materials with no segregation between medical materials and their industrial-grade alternatives. Properties such as tensile strength, flexural modulus and melt flow, to name a few, were the only design parameters considered to be critical. A new definition of medical device design optimization, including factors such as environmental concerns, product stewardship, biocompatibility, end-of-life management, recycling, reusability, sterilization chemistry and supply chain complexity are all considered essential today.

The recent global push to separate medical-grade polymers, coatings, inks, adhesives and so forth from their industrial-grade counterparts is worth noting, as this is a big technological turning point for the medical industry. I would add that this is, in fact, business vital, since this movement will enable formulation lock down, enabling compliance to current and future regulations. Heightened scrutiny will prevent the selection of materials with substances of very high concern (SVHC). You don’t get a second chance—it is important to choose the right material as the cost for choosing the wrong one could be staggering. 

With end use in mind—for example, short-term, patient-contacting medical device applications—material formulators are evaluating and selecting vegetable-based additives and oils and eliminating animal-based derivatives from their polymer chemistries. These advances would not have occurred without a trigger or a source of demand. One may ask, “what good is technology if there’s no material to support it” or, for that matter, “what good is advancement in material development if there’s no use for it?” These questions go hand in hand.In the same vein, technologies that were limited to consumer markets a few years ago, such as wearables and fitness trackers, are now finding their way into the medical industry. From my vantage point, shifts in customer expectations are spurring the evolution in medical materials, since there is currently little to no difference between medical wearables and their runway counterparts. A patient wearing prescription eye glasses would like to combine the medical benefits with a fashion statement.

Regulatory requirements also are driving changes in materials formulation chemistry, and materials developers are devoting considerable resources to addressing this need. I would note that, even though some materials are now finding their way onto the restricted list—California’s Prop. 65, for example—replacement materials are being developed. Medical tubing is now available in TPU, TPE and silicone, which is quite an achievement. Some manufacturers are even going to the extent of removing ingredients that do not meet current regulations from their legacy material portfolios and replacing them with medical-grade alternatives to meet new requirements in documents such as 21 CFR 74, 21 CFR 73, ISO 10993 and USP Class VI.

Some materials OEMs have escalated technology enhancements and are now offering bovine-free materials and issuing certificates attesting to the environmental sustainability of the vegetable-derived sources for their materials. That is the case with Trinseo and implantable surface modifiers (Stearates) backed by a Kosher certificate of compliance.

Another exciting recent development involves the availability of ultra-high-performance polymers. Currently, there are more than four different sources for polyether ether ketone (PEEK), ultra-high molecular weight polyethylene (UHMWPE) and liquid crystal polymers, all of which used to be single sourced. This profusion of premium material options, including manufacturing capability expansions, will steadily drive down cost and significantly improve the continuity of supply.  

When it comes to new and exciting materials for digital health, the list is endless. This design space is very complex and, therefore, is forcing collaboration and integration with other markets. Regarding material technologies with built-in antimicrobials, premium grades such as PARA, PPSU, UHMWPE, PFA, PEEK, PEI, PAI and PBI are preferred, as they are inert to most hospital cleaning products and sanitizers. Meanwhile, medical device OEMs are exploring new design concepts for consoles and instruments by borrowing ideas from other industries such as consumers goods and heavy industry for their powered handhelds with and without cores. Vendors are now looking at standardization of shrinkage properties of materials across technologies for seamless material substitution opportunities, which is an added value.

Other potential benefits on the horizon include the development of composites with impregnated variable resistance and temperature-sensing capabilities. This was requested of me a few weeks ago by one of my onsite head design engineers, John Hibner. 

Implantable materials manufacturers such as NuSil, Invibio, Lubrizol, Solvay and Advanced Polymers are furthering progress in the development and commercialization of premium and implantable materials, including silicone, PEEK, PLA and PPSU, for wearable applications. Their efforts serve as a backbone for the next generation of patient-care devices within what has been called the “patient care continuum”: Implants with healing aids, sensing aids for cancer identification, vision sensors, radio-opaque tracers, connectivity and the potential encapsulation of medical electronics.

Finally, the seamless integration of virtual manufacturing and state-of-the-art logistics—think Amazon—will take 3D and 4D printing to a whole new level as materials suppliers advance flexibility in the distribution and sale of 3D-printing materials to consumers.

Breakthroughs we are seeing in medical materials today are just the tip of the iceberg of what is coming, since technology continues to drive innovation. The field of smart polymers, for example, is rife for exploration. Uninvestigated technologies such as oxygen-detection materials for touch screens, lubricants that can be reactivated after multiple autoclave cycles and autoclave-resistant lubricants and coatings need attention. Printable pharmaceuticals and swallowables that perform diagnostics and transfer data to remote devices are also an untapped and unmet need.

Jackie Anim is Principal Material Engineer and Subject Matter Expert at Ethicon (Cincinnati, OH), part of the Johnson & Johnson (JNJ) family of companies. She provides leadership and direction in the identification and selection of polymer-based materials for sustaining and new product development involving digital and non-digital medical devices and instruments at Ethicon and other JNJ businesses. 

A certified Six Sigma green belt champion, Anim has more than 24 years of experience in material science and material application engineering. In 2015, she received the JNJ Global Surgery Award for Scientific Excellence for her role in leading the development and implementation of an injection moldable electro-mechanical proprietary material for harmonic powered medical devices.

Anim is a member of the Society of Plastic Engineers and the American Institute of Chemical Engineers. A published author, she holds nine patents involving plastic applications.