Del R. Lawson, who currently leads new product development and commercialisation efforts in 3M’s medical solutions division and Tony Kaufman who leads new business ventures for 3M’s medical materials and technologies business, discusses what you need to know to avoid medical device adhesive failure.
While there’s no recipe for designing stick-to-skin medical devices, an adhesive is likely to be a key ingredient. Innovations in adhesive and wearable technology have transformed the way doctors and patients are able to make critical medical decisions. They’re mobilising chronic disease management and lending patients the freedom to monitor and manage their health on their own – anytime and anywhere.
Although wearables have simplified the care management process, the engineering that brings these products to life is no easy feat. With so many device and user variables, thoughtful adhesive selection is essential to develop a design capable of achieving the intended purpose and wear time while delivering accurate readings under a variety of circumstances.
But what happens if adhesive selection isn’t given proper consideration? We list three important things to consider.
1. Compatibility with the manufacturing process
It’s important to confirm your chosen adhesive is compatible with the manufacturing process intended to mass produce the final product. Thinking beyond the design phase to manufacturing can help dodge a number of ways adhesives can derail the project. For example, soft adhesives have the potential to gum up equipment during production and converting processes. Other adhesives may be unable to withstand the speed and friction of a specific method or the liner materials could break during production, which may compromise integrity. Should any of these mishaps occur, you could run into problems with assembly line flow and function, such as unscheduled stops for cleaning. Being proactive and engaging an adhesive supplier early in development can help you to bypass potential redesigns, avoid cost overruns and proceed with bringing your device to market.
2. Choosing the right adhesive for the device
Choosing the wrong adhesive can have undesirable effects even after the device is manufactured. When it comes to stick-to-skin products, it’s usually the adhesive’s main job to keep the device adhered to the user’s skin for a specified wear time. If the adhesive fails, the device could prematurely detach and/or provide inaccurate readings. For continuous glucose monitors and other devices that help manage chronic illnesses, prompt and accurate data is critical to users’ health, independence and ability to manage their care at home. In these applications especially, adhesive failure would be simply unacceptable.
For adhesives holding device components together, reliability is one of the main concerns. Components need to stay in place in order to provide results users can trust. Another potential device issue adhesives can cause involves the electronic component layer de-bonding if it’s incompatible with other materials. You need to be sure that the pressure sensitive adhesive you select ensures and maintains a consistent connection.
Not only is it troublesome when device materials fall apart, it can be just as problematic when two incompatible materials combine.
3. Considering the risk of injury to the user
Since human skin is a living, breathing organ that’s constantly regenerating itself, it is different than other substrates, like metal or plastic. In order for it to function normally, skin needs to be able to move, flex and expel moisture. Two of the most common issues to be aware of are allergic reactions and medical adhesive-related skin injuries. Over-designing to create a super sticky product that provides a longer wear time than is intended could lead to undesirable outcomes.
Design and device issues are largely preventable if you select your materials and adhesive carefully.
Three key questions to think about when you start mapping your design and development plan are:
- What are the needs of the substrate and user?
- What environmental factors will the device encounter?
- How long will the device be worn?
In addition to considering these questions, seek the counsel of a material supplier or adhesive expert that has experience with designing, researching, and testing adhesive technology.