Designing Portable & Wearable Medical Technology

A fourteen year old Caucasian girl reads her blood sugar level by placing her reader next to her pump in her arm as she is about to leave for school.

A girl reads her blood sugar level with the help of a medical wearable device

By Eric Smith, Printed Circuit Solutions Business Development Manager, and Rob Irwin, Printed Circuit Advanced Development Engineering Manager

Recent advances in medical technology, along with the expansion of 5G technology, have established a new standard for wearable medical devices, according to a 2021 Research and Markets report. Medical professionals and patients alike expect the devices to be both highly effective and able to withstand daily usage. Meeting these criteria is critical to ensuring that a product is safe, usable and practical—and requires thoughtful design and highly reliable components.

To make wearables comfortable and effective, designers must balance human interaction factors and comfort needs with features and function. This balance is achieved by a combination of innovative human-centered design and the optimization of components and materials that enable a cutting-edge solution.

Understanding the Ideal Design

PCS Wearables

Wearable Device Measuring Heart Rate

Developing wearables with both form and function in mind is a necessary approach to on-body device design, as discussed in a previous Molex blog. The first step in designing a successful product is picturing the perfect end result. Even if the initial approach is purely aspirational, outlining what the ideal product looks like and the components and capabilities required can help spark innovation.

What does a best-in-class wearable device look like? It might be a device that uses capabilities most people are comfortable with, such as touch-sensor technology with appropriate sensitivity. If it’s a worn device, such as an electrocardiogram (ECG) monitor, then a discreet profile built with lightweight and comfortable materials will likely be prioritized. If it’s a platform with multiple settings, such as a cancer drug-delivery device, the user interface should operate simply and intuitively. Indeed, the more complex the product, the higher the potential to create confusion or frustration for the user.

Similarly, a wearable medical device with a capacitive touch interface should mask the complexity or number of settings and intuitively offer only relevant options. For example, the interface might only reveal buttons or keys that need to be pressed based on the current need, and once an option is selected, the appropriate buttons should be displayed for the next step, and so on.

To provide a productive user experience, designers and architects must focus on an optimized solution that anticipates key use challenges and identifies how those can be masked or overcome.

Solving Design Challenges

PCS Wearables

Molex Medical Wearable Circuits

Designing a medical device that is both wearable and functional involves addressing various challenges, depending on how the device is used. For example, a device made for round-the-clock functionality, such as a blood glucose monitor or an insulin pump, will have a different design from one that is used for a limited time in a clinical setting.

Achieving Durability 

For the sake of comparison, let’s review the design challenges of a wearable glucose monitor versus an insulin pump. First, these devices must be able to withstand constant use in any environment, whether the user is in the shower, on an airplane or playing sports. And monitors and pumps should be able to endure a variety of conditions, from the sun’s UV rays to both intentional and unintentional chemical exposure. As a result, designers of wearables must focus on utilizing materials that can withstand the rigors of daily use in everyday life. 

Balancing Form Factor and Weight with Ruggedness

The thickness and weight of the device is a critical variable that must be considered as well. A lighter-weight glucose monitor will encourage patient use, while a lower-profile device is less likely to be bumped or get in the user’s way during day-to-day activities.  

Choosing Appropriate Materials for Required Performance 

Designers of medical wearables used in clinical settings don’t have to be as concerned about the rigors of everyday living, but they still must be mindful of key considerations such as the types of connectors and cables used for diagnostic and therapeutic devices in clinical settings.

Products like electrodes may either be used to sense body signals or to apply voltages on the skin. The function required by the electrode dictates how it’s designed and what materials are used. For example, sensing electrodes require low impedance and highly conductive hydrogels, but stimulation electrodes often don’t require the same signal integrity and can, therefore, use lower-cost materials. The length of time the electrode needs to remain on the body also dictates the type of materials and adhesives used in its construction.

Medical Interface Solutions

When designers partner with experienced engineers or manufacturers leveraging a wide breadth of component options, an ideal form factor for the wearable device can more often be achieved by using state-of-the art components and technology. 

Medical wearable devices are being created by medical OEMs that have designed in Molex technology at the component level. The entire medical ecosystem continues to rely on companies like Molex to assist in the creation of innovative designs while using the optimal form factors for the unique functional requirements. The broad array of flexible and high-performing printed circuit solutions from Molex is combined with extensive manufacturing capabilities and engineering support to further enable the adoption of medical devices that prioritize the user experience.

Learn more about how Molex helps its customers design and deploy the next generation of medical wearables, thereby Creating Connections for Life.