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Materials Impact Medical Device Design Trends

Mon, 06/03/2013 - 2:22pm
Sean Fenske, Editor-in-Chief, MDT

There are an array of factors that impact the design of medical devices, from available components to healthcare trends. In this Roundtable presentation, participants spoke to the way in which healthcare trends are impacting material development and, as a result, how materials are then impacting medical device design.

After exposure to aggressive chemicals used to help reduce healthcare associated infections, Eastman Tritan copolyester retains clarity and integrity and demonstrates excellent environmental stress crack resistance (photo courtesy of Eastman).Medical device designers have to follow the trends in the healthcare industry closely to be sure they are addressing the current needs of both medical professionals and their patients. The suppliers who support those design engineers have to not only follow those same trends, but look ahead to see where they are leading in order to get in front of their customers and offer products to fulfill any future needs. With material suppliers, it’s no different. Today’s engineers need to address a number of issues in the development of their medical devices. These include the fight against healthcare associated infections, addressing the need for sterilization of those devices and the use of cleaning chemicals on them, and the movement of healthcare out of the hospital and into the hands of patients. Material offerings enable design engineers to resolve concerns in all of these areas.

Antimicrobial Materials
One area in which materials can make a huge impact is on the effort to eliminate healthcare associated infections (HAI). Since insurance companies have established rules against reimbursement for HAIs, it is in the hospital’s best interest to prevent them as best as possible. Therefore, devices that can aid in this effort, such as those made with antimicrobial materials, will be preferred over those without that benefit.

“Antimicrobial materials and/or coating have been used in catheters, wound dressings, and other likely infection routes (such as implantable devices) for many years,” explains Scott Fallon, general manager of global specialty products, Innovative Plastics at SABIC. “However, medical device makers are considering the merit of these high performance materials in many more devices today, such as high touch surfaces like bed rails and electronic touch pads due to heightened awareness of the problem of HAIs.”

Gopal Saraiya, global segment leader of medical devices at Eastman Chemical Company, confirms that his company is also addressing this issue with antimicrobial solutions. “Currently, the company is exploring applications that come in direct contact with patients’ skin. Skin-contact applications made with sterile and/or antimicrobial materials can help reduce the flow of pathogens during fluid transfers, during which there is the potential to develop infections.”

The Breastlight examination device from PWB Health Ltd. uses SABIC’s CYCOLOY polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) HC resin to enhance usability in the home, enabling the healthcare industry’s move toward device portability and enhanced aesthetics (photo courtesy of SABIC).The attention being given to HAIs by hospitals and medical professionals will likely increase the insistence by them to have devices that are utilizing antimicrobial materials. Fallon offers insight into what designers might be able to expect from a new wave of such offerings. “Current generations of antimicrobial materials typically focus on migrating an active species (such as silver ions) to the surface in order to achieve desired performance, but next generations of materials will likely contain better engineered surfaces and/or inherently antimicrobial materials and/or coatings.”

Sterilization/Chemical Resistance
Antimicrobial materials are only one method with which to combat the incidence of HAIs in hospitals though. A more “traditional” approach involves the use of cleaning chemicals and/or sterilization techniques. These safety protocols can wreak havoc on medical devices as the chemicals, heat, or radiation can adversely impact material performance, causing an array of issues in the devices.

Aaron Updegrove, marketing manager for Healthcare Markets at Saint-Gobain Performance Plastics explains further. “In the medical industry, sterilization of the finished product, along with repeated sterilization of multi-use devices, such as surgical tools, is a fact of daily life with regards to ensuring patient safety. The industry relies upon three common methods for sterilization: Steam, Chemical and Irradiation (examples include an autoclave, ethylene oxide, or EtO, and gamma irradiation, respectively). The device manufacturing industry has also recognized that materials potentially can react differently to these sterilization methods. For example, thermoplastic components can become brittle after steam sterilization, or polymeric materials may incur a shift in physical properties after exposure to gamma sterilization. As a result, both material and device manufacturers routinely test the impact of different sterilization methods on their products and materials, determining the most appropriate sterilization methods for their devices, or conversely, manufacturing devices from materials that are compatible with commonly accepted sterilization methodologies.”

Updegrove goes on to offer a solution. “Advances in materials can help to overcome traditional limitations. Silicone valves, in particular, can be problematic for medical device designers due to their tendency to re-heal or re-knit after gamma sterilization. This issue speaks to the need for raw material and component suppliers to custom formulate materials that improve performance.”

Saraiya expands on this solution. “With an increased use of aggressive sterilization methods and harsh chemical cleaners, OEMs are turning to materials that are less affected by these disinfectants and sterilization methods. In turn, health facilities are turning to devices made with these materials. Material suppliers need to offer a product that withstands these aggressive systems, and OEMs need to understand the effect sterilization methods and chemicals will have on devices early in the development process in order to select the most appropriate material for the application and environment in which it will be used.”

Home Healthcare
With more medical technology being used directly by patients in their homes, design has to be adjusted to account for the new users’ environment and interaction with the device. While material selection is just one aspect of this, it can be a critical one.

“The increase in home healthcare and patient-directed care has created trends for greater portability, miniaturization, and greater aesthetics—all of which combine to support patient acceptance and compliance with treatment protocols. These trends, in turn, are driving a strong need for high performance engineered thermoplastics that can provide ease of processing and assembly, and superior mechanical properties to address these trends,” explains Fallon.

Saraiya shares this viewpoint. “Materials that exhibit processability and design flexibility should be considered for portable device development. These materials provide good ergonomics and aesthetics to devices, making them user friendly and ideal for in-home use. Additionally, by using materials with high chemical resistance, home healthcare personnel and even patients can use disinfectants and chemicals readily available at home so as not to affect the functionality of the device.”

Conclusion
While materials are simply a single component in addressing these trends in healthcare, they are an important one. As the “building block” of all medical devices, materials have the potential to have a significant impact on device design while also offering a host of additional benefits. Design engineers need to maintain close communication with their material supplier experts in order to ensure they specify the best material for any product they are developing.

Full Responses
To see the full responses of the participants, view these links:

Combating Infections with the Right Materials - Gopal Saraiya, Global Segment Leader—Medical Devices, Eastman Chemical Company

Addressing HAIs and Antimicrobial Materials - Scott Fallon, former GM, Global Specialty Products, SABIC Innovative Plastics

Silicone Offers Options for Medical Device Design - Aaron Updegrove, Marketing Manager, Saint-Gobain Performance Plastics, Healthcare Markets

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