Component Selection Considerations for Sensor-Driven Medical Devices

Ignoring these factors can significantly impact market viability.

Darren Gilmer, Senior Engineering Manager of Product Development, Intricon, Senior Engineering Manager, Product Development

February 16, 2024

7 Min Read
Image courtesy of Intricon

Companies introducing new sensor-driven technology into the biosensor market must make careful, strategic decisions during the design phase if their products are to compete with established players. Often lost in the excitement of burgeoning product ideas is the need for component compatibility, but this is a critical consideration that significantly impacts market viability.

Choosing components for sensor-driven medical devices is challenging. They must be compatible with each other as well as demanding environments — especially in wearables and implantables — and with assembly processes for scalable manufacturing.

Contract development and manufacturing organizations (CDMOs) routinely consider component compatibility during the design phase, as they understand how incompatible components can derail production, force recalls, threaten profitability, and even put lives at risk. Those pitfalls can be avoided with a Design for Manufacturing (DFM) approach.

The following discussion details four component selection considerations that companies should address during the design phase to lower costs, reduce risks, and accelerate timelines for sensor-driven medical devices.

1. End of life monitoring in design and production

Obsolescence is a major concern for biosensor and microelectronic device manufacturing. Unlike consumer electronics, which often consider planned obsolescence a feature, medical devices must reliably perform for years in demanding environments. If even one component on the bill of materials reaches its end of life (EOL), it could disrupt the entire supply chain.

Consider a real-world scenario in which a component has reached its end of life and is no longer available:

  • Without the component, manufacturing halts, and OEMs can’t meet market demand.

  • Patients may not have access to the life improving and potentially lifesaving biosensors device.

  • Unable to find replacements or alternates, the OEM could even go out of business.

OEMs must proactively plan for sustainability with the understanding that some components will inevitably be discontinued and require replacement.

Proper monitoring and early notification for EOL components is critical to avoid devastating supply chain disruptions that could delay product timelines by months. For example, an integrated circuit (IC) could have a six-month validation cycle plus three months of regulatory activities, requiring a nine-month lead time. Once you identify a replacement component, you must build prototypes, perform any required testing, build validation units, revalidate it, and address regulatory issues before the supply chain is disrupted.

If there are no replacement options available, you’ll need to redesign the device to achieve the same functionality. For example, a printed circuit board assembly (PCBA) might require a redesign due to a discontinued package size. The original gull wing might have been a 12-legged component, but that package size is EOL, and its replacement is a 12-pin ball grid array package that doesn’t fit the PCB or flex pad layout. Since the new component doesn’t fit the board’s form factor, the board layout must be redesigned to accept the new package size — a lengthy process that extends timelines.

All this underscores the need to not only have a plan for development in the face of obsolescence, but also to address inevitable costs. EOL surveillance is critical, and OEMs must be prepared to act immediately once an EOL alert is issued. Recommended steps include:

  • Notify the customer and make them aware of any potential supply chain disruptions

  • Develop a plan for addressing the EOL component (including any redesigns)

  • Identify the EOL timeline and availably of EOL component in distribution

  • Determine the quantity sourcing should purchase, above and beyond current safety stock quantities, allowing continued use of EOL components for as long as required

  • Negotiate with the original manufacturer to see if they will continue production

  • Evaluate alternate components to use once the EOL component is no longer available

  • Revalidate with the replacement component

It’s crucial to choose a manufacturing partner that not only has a formal surveillance process but also a process in place to alert you and manage EOL. Without a good partner and management process, startups and small to mid-sized businesses are at risk, since they don’t have the same buying power as large manufacturers. It’s not enough to simply subscribe to EOL alerts. Your partner should have an organizational solution for managing obsolescence and a proactive plan for when a component reaches EOL. This also applies to any materials used in the manufacturing of a sensor-driven medical device.

2. Biocompatibility and environmental conditions

Biocompatibility is vital for performance and safety, as sensor-driven medical devices need to function for years without failures that could require premature removal or even cause life-threatening situations. Implantable and wearable device components and materials, then, should be:

  • Safe for subcutaneous applications

  • Compliant with ISO 10993 biocompatibility standards

  • Corrosion-resistant to prevent adverse reactions when exposed to tissues, blood, and other body fluids

Ultimately, it is the designer’s responsibility to ensure their devices are biocompatible, though some CDMOs offer consulting or testing services to help select compatible components and materials.

Environmental conditions are another important consideration. Components and materials might perform differently at various temperatures, humidity levels, and altitudes, so it’s important to consider where in the world the device will be used and ensure its components will perform reliably in those environments.

Production environment impacts cost and manufacturability, so it’s a key consideration for material selection. For example, an adhesive that relies on moisture at atmospheric conditions to cure could create significant process variability between seasons and locations. It will cure differently in hot and humid conditions — such as in summer or Costa Rica — than it will in cool and dry conditions — such as in winter or Minnesota. Some components and materials might require controlled storage conditions and controlled environments or clean rooms for manufacturing to maintain ideal production environments.  If this is not addressed properly, it could lead to process variability, high scrap costs, and potential field failure.

Exercise due diligence when choosing components and materials for medical products to ensure manufacturers qualify and stand behind their products and the usage application. This applies to every component in your device; for electronic assemblies, that includes everything from the PCB or flex fabrication materials, adhesives, and encapsulants to the SMT chip components, capacitors, resistors, and ICs.

3. Regulatory considerations

Prioritize regulatory considerations during the design phase to ensure components and materials comply with international regulations such as RoHS and REACH. Though the onus is on the designer to meet regulatory requirements, it’s a good idea to work alongside a reliable partner with proven, repeatable delivery processes. Be sure to verify ISO certificates and perform due diligence that could include on-site audits when evaluating potential suppliers and manufacturing partners.

Biocompatibility considerations should be addressed early on during the component selection process. Seek materials that have already been vetted and validated for biocompatibility to reduce the likelihood of adverse reactions, avoid costly redesigns, and increase the chances of regulatory approval.

Other considerations include:

  • Ensuring components are not affected by conflict material concerns, which could disrupt the supply chain

  • Verifying no use of animal tissues or latex materials (note that it can sometimes prove challenging to obtain such information from manufacturers)

  • Considering the market you’re serving, including geographical location and materials or substances that are banned or have limits

You should also anticipate obsolescence as part of your regulatory considerations. When a component reaches EOL, it could prompt a design change that requires a note to file or even a new FDA submission — a potentially costly process that delays production. Again, establish a plan for handling obsolescence at the outset and choose components and materials accordingly.

4. Beware counterfeits

People might not be aware that when manufacturers have extra components, they can sell them to brokers for resale – but when you deal with the resale market, there’s always a risk of counterfeit components.

Counterfeit components are dangerous to patients and manufacturers as they:

  • Likely do not go undergo proper testing

  • Can fail and cause patient inconvenience, injuries, or even death

  • Can force costly recalls and severely damage a manufacturer’s reputation

If you’re buying components from a broker, mitigate risk by having them analyzed to verify authenticity. If your brokerage doesn’t offer a test service, send your parts to a trusted test lab that does. There are specialized analysis labs that can perform X-rays, probes, functional testing, and other procedures to confirm authenticity.

Keep in mind that a qualified manufacturing partner can help you address component selection considerations and avoid pitfalls that could derail production, force recalls, threaten profitability, or put patient lives at risk. When selecting a contract manufacturer or CDMO partner, ensure that they take responsibility for the production lifecycle of your device — and that doesn’t stop when they win your business. Choose a dedicated partner that prioritizes accountability and protects its customers with the ability to produce your device over its entire lifecycle.

Darren Gilmer is senior engineering manager, product development, and Craig Sandbulte is vice president, corporate quality assurance and regulatory affairs, at Intricon. For four decades, Intricon has improved and extended people’s lives by developing and manufacturing sensor-driven micromedical devices. Intricon partners with medical device companies, providing unique microelectronic expertise including miniature molding through final assembly and regulatory guidance, supply chain optimization, and scalable production, exclusively for the medical market. Intricon brings the world’s smallest, smartest new and next generation devices to life.

About the Author(s)

Darren Gilmer, Senior Engineering Manager of Product Development, Intricon

Senior Engineering Manager, Product Development, Intricon

Darren Gilmer is senior engineering manager, product development at Intricon.

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