by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Medical Engineering in the Age of COVID-19

Medical Engineering in the Age of COVID-19

Due to the COVID-19 pandemic, there has been an increase in worldwide demand for thermal scanners, respirators, and ventilators. This has been accompanied by an increased need for medical disposables such as gloves, respirators, medical masks, face shields, single-use syringes, and drapes. As a result, medical engineering and manufacturing both have temporarily shifted their focus and the results are fascinating.

3D printed hand sanitizer clasp

Additive Manufacturing

Shortages of some items have led to innovative design and manufacturing, much of it involving additive manufacturing using polymer materials. For example, Old Dominion University has been 3D printing masks and mask components made from PLA and designed so that they can be easily sterilized and reused. Europe has already seen companies in the 3D printing industry volunteer their equipment and knowledge to aid in manufacturing replacement parts for critical equipment such as oxygen and respirator valves, and many other countries are doing the same thing. 

Ventilator Designs

Many countries, including the United States, are worried about a potentially deadly shortage of ventilators. Various technology firms worldwide such as Nvidia are working to design critical care devices that can be produced both quickly and inexpensively. NASA has been given permission to start production of their emergency use ventilator that can be manufactured and built quickly, with the only drawback being its limited lifespan. 

In addition, ventilator manufacturers such as Medtronic have ramped up production and publicly shared their design specifications for one of their ventilator models so others can help meet this critical need.

Innovation

Engineers all over the world are looking for ways to make the treatment of COVID-19 patients easier and safer for medical personnel. For example, engineers in the Boston area have teamed up local doctors to develop a 3D printed bracket that will hold the tube and respirator hookup together in ventilator patients. The goal is to prevent release of the COVID-19 virus into air when these connections come undone, as they often do. 

Others at Boston University are looking at polymer nasal swabs that will do a better job of collecting mucus for COVID-19 tests, which could increase the reliability of testing and help with testing material shortages. At the Oxford Institute of Biomedical Engineering, engineers are leveraging wearable technology to allow nurses to track the vitals of COVID-19 patients who are not on ventilators and thus must remain mobile to recover.

Conclusion

The COVID-19 pandemic has changed how much of the world lives, and has affected a shift in the focus of many engineers. Trademarks of this shift include the use of additive manufacturing for PPE and replacement parts for life-saving equipment, a fresh look at ventilator designs that emphasizes manufacturability and availability, and the birth of innovative approaches to medical issues related to the pandemic. And, in this midst of this, companies like Advanced EMC are still working hard to make available the right polymer seals and bearings needed for medical equipment. 

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Polymers for Implantable Devices

Polymers for Implantable Devices

Due to the growing demand for implantable devices, there is also a growing demand for approved materials for use in manufacturing these devices. Polymers are an increasingly important material for use in medical implantable devices, with UHMW PE and PEEK being the most popular.

The Implantable Device Market

According to the FDA, implants are defined as devices intended to stay within the body for more than 30 days. Implantable devices are an ever growing market that was already worth $96.6 billion back in 2018 and expected to reach $143.3 Billion by 2024. These implantable devices include joint replacements, deep brain neurostimulators, pacemakers, insulin pumps, gastric stimulators, and more. 

Requirements for Implantable Device Materials

When it comes to materials, the implantable device market is divided into metals, ceramics, polymers, and biologics. For implant materials to be considered safe, they must remain stable in the presence of body fluids, not elicit an adverse response from the host, and, if applicable, meet requirements related to strength, stiffness, and performance. Long-term long-term biostability and biocompatibility are also key, as well as compatibility with medical imaging methods. For load bearing implants such as those used in hip replacements, how a polymer responds to wear can also be critical.

Implantable Polymers

The two most widely used implantable polymers are FDA approved grades of UHMW PE (Ultra-High Molecular Weight Polyethylene) and PEEK (Polyether ether ketone), although there are other polymers in use.

UHMW PE for Implantables

UHMW PE has been in use for orthopedic applications for over 30 years. UHMW PE can be found in joint replacements and spinal disc implants, where properties such as a low coefficient of friction, excellent fatigue resistance, and good impact strength are vital. Its primary drawback is a lack of strength, which is why it is not used in applications that involve significant load bearing. Note that UHMW PE can be machined or molded, but cannot be injection molded.

PEEK for Implantables

Implantable PEEK offers some properties similar to UHMW PE, including good impact strength and a low coefficient of friction. It is also self-lubricating, possesses a high compression strength, and offers good wear resistance. As a matrix material combined with carbon and graphite fibers, it can be customized to offer improved properties related to strength, stiffness, and dimensional stability. Unlike UHMW PE, PEEK is more versatile when it comes to manufacturing: it can be machined, molded, extruded, and even powder coated. One of PEEK’s more recent applications is implantable spinal cages, which requires significant load bearing capacity.

Other Implantable Polymers

Other polymers for implantables include PSU (Polysulfone), which is known for its toughness, dimensional stability, and moldability. PSU can be found in implantable devices such as shunts and access ports. Another polymer is PPSU (Polyphenylsulfone), which combines toughness with transparency and is often used as a coating for wires and leads. Both of these polymers also provide excellent tensile strength and biocompatibility.

Conclusion

Materials for use in implantable devices must be stringent requirements, and for good reason. There are a host of issues, such as biocompatibility, biostability, wear properties, friction, stiffness, and strength, that all depend heavy on the application. However, there are polymers such as UHMW PE and PEEK whose performance and safety have been well established.