Designing a medical device demands careful consideration, and one of those most important features to consider is sterilization. Having strict hygienic procedures isn’t just the duty of the hospitals, after all; it begins with the manufacturer. Because there’s a concern for contamination with reusable surgical instruments and implants, it’s important to take their unique purposes into account during the material selection and manufacturing process.
 
As medical device manufacturers, we must focus on more than just the bottom line. We have a responsibility to create safe and effective products, not just because it’s FDA-mandated, but because it’s the right thing to do.
 
The following is a list of initial considerations you can take when choosing a medical device manufacturer to prevent problems with contamination risks and sterilization.
 
Material Selection
Having worked with precision plastic machinists the past 27 years, I know firsthand that material selection is a highly crucial aspect of application design. Even high-performance thermoplastics have different chemical and thermal resistances as well as strengths depending on their environment, and not all of them are equally sterilization-compatible. Your manufacturer should be able to explain which material they recommend using and why, and what sterilization methods are most compatible with the chosen polymer or composite material.
 
For example, PEEK is one of the most chemically resistant plastics on the market today. Its reliability as a material and biocompatibility make it popular for a wide variety of applications, including reusable trauma and surgical instruments. This is in part because PEEK performs well and doesn’t lose mechanical properties during steam sterilization, even after 1,000 autoclaving cycles, which are largely considering a fast, reliable and inexpensive method of sterilizing reusable devices. This combination of heat and moisture is highly successful in killing microorganisms.
 
On the other hand, several alternative medical-grade thermoplastics can only withstand a much more limited number of autoclaving cycles. Polyamide (PA) and polycarbonate (PC), for example, can withstand less than 100 cycles. That doesn’t mean these thermoplastics can’t be used in medical applications (on the contrary, both are widely used today in single or limited use devices) but that their preferred sterilization methods are different.
 
Polycarbonate’s clarity and high strength have made it a critical material for applications used in cardiac surgery, renal dialysis, surgical instruments and IV connection components. While it can be sterilized through autoclaving, it can withstand more sterilizations through ethylene oxide (EtO) and irradiation (gamma and electron-beam). Similarly, polyamide medical applications such as medical tubing have good compatibility with the same methods as polycarbonate.
 
There are other factors that go into material selection based on your unique application, but be certain you understand the sterilization compatibility of your polymer, metal or other material—and more importantly, that your manufacturer understands it, too.
 
Strict Hygienic Procedures
This brings us to another point: the actual manufacturing of the device must be done with strict hygienic procedures in place. For example, if you’re working with a shop who works with both metal and plastic materials, be sure that they don’t machine both types of materials in the same facility or machines. Even the tiniest sliver of metal embedded in a plastic part can have widespread ramifications in medical applications. The last thing you’d want is an electrical, contamination or MRI problem in your medical device.
 
Another question is which lubricants and coolants your machinist is using. Metal machining companies typically use oil-based cutting fluids, but these can imbed and contaminate polymer materials resulting in premature failure. Some thermoplastics are especially sensitive to petroleum-based liquids, such as Polyetherimide (PEI): a high-performance thermoplastic commonly used in medical instrumentation. This type of material can degrade or experience delayed stress crazing when in contact with these liquids during the machining process, while other materials are hydroscopic and will absorb the oils.
 
Whether you’re working with metal, plastic or glass, make sure you hire a manufacturer who is familiar working with both your material and your industry. Look for references, testimonials, years of experience and clear examples of similar work they’ve done in the past.
 
Certifications and Standards
I’ve placed the most obvious consideration last: check for industry certifications and standards. This is the most clear and consistent way of ensuring your manufacturer takes the matter of contamination seriously. I’ve outlined a few that you’ll want to look out for specifically and be familiar with in this industry.
 
ISO 13485 is an internationally agreed upon standard for organizations involved in the design, production, installation and servicing of medical devices and related services. It specifies requirements for a quality management system where a company demonstrates it can consistently meet customer and regulatory requirements while providing these products and services. Confirm that your manufacturing partner is certified to the most recent 2016 revision.
 
Finally, you’ll want to check that your manufacturer is registered with the FDA. In medical manufacturing, FDA compliance is non-negotiable, even for contract manufacturers; Don’t forget to look for this at the start, no FDA registration means the business is not serious about providing their OEM partners with FDA registered devices.
 
Conclusion
Both manufacturers and health professionals must be able to work together to prevent contamination in medical devices. These are just a few ways to help ensure you’re working with a manufacturer who understands the risks, requirements and considerations of the medical industry, but educating yourself doesn’t stop here. Thoroughly interview your potential manufacturer, be clear about your application’s end-use and ensure there’s a check for quality assurance every step of the way. The more we work to prevent contamination, the more successful we all will be.
 

---

John MacDonald is the president and CEO of AIP Precision Machining. MacDonald has over 27 years of experience in precision machining polymers and composites for applications within the medical and life sciences, aerospace and defense, specialized industrial and power and energy markets. He received his degrees from Embry-Riddle Aeronautical University and Wentworth Institute of Technology. For more material expertise regarding high-performance thermoplastics like PEEK, RADEL and ULTEM, visit here.