For other end uses, such as cardiac monitors worn continuously over a two-week period, the ability to manage sweat and bodily fluids is a much greater priority. Without a highly breathable material, the patient may not be able to tolerate the device, which could lead to serious skin sensitivity and irritation problems. Working together with the device manufacturer, an experienced industrial designer, material manufacturer, and medical specialist converter can suggest both skin-contact and construction materials to manage varying levels of moisture — through allowing vapor transmission or moisture absorption.
There is both art and science involved in choosing the right materials, testing them, and integrating them into a fully functional wearable device. For example, the materials manufacturer, working through the specialist converter, will be able to provide biocompatibility reports and documentation for each material used in a skin-contact adhesive. These will include results for cytotoxicity, irritation, and sensitivity according to market standards (ISO 10993). The material data sheet will specify the adhesion strength and other key performance characteristics. These are critical scientific metrics.
However, there also is a need for a great deal of qualitative analysis. An experienced wearable device converter should be skilled in the art of wear-test experimentation. How long does a material truly adhere under a variety of conditions? Will it stay on the skin for a week with regularly showering? How will it handle intense movement and profuse perspiration from vigorous exercise? How does a patch feel on the skin over time? How do these factors vary depending on patch placement on different parts of the body? How easy is it to remove from the skin? The answers come from years of wear testing and trial runs — of putting oneself in the patient’s skin, so to speak — to see how materials truly perform. And this can be more art than science.
Product development of wearable devices requires strong data to back up claims for biocompatibility, wear time, and moisture management. But it also benefits from the softer skills, such as a refined sense for which design elements will deliver the most effective performance along with aesthetic appeal and comfort. For without a good patient experience, a wearable device isn’t likely to be worn as prescribed, if at all.
- IDTechEx. (2016, July 14). Wearables: The Next Big Thing or Next Big Disappointment?
- Market Data Forecast. (2016, December). Global Wearable Medical Device Market.
- Tractica. (2016). Smart Clothing and Body Sensors.