Today’s smart skin patches can incorporate a broad range of functions, employing hybrid printed electronics to enhance medical sensing capabilities and improve patient outcomes. Along with enormous potential, however, there are also complex design challenges.

The advance of electronics miniaturization is opening new frontiers in Medtech, including in the field of adhesive skin patches. In the past, a skin patch might contain a single wired sensor but today’s smart skin patches incorporate a broader range of functions. Hybrid printed electronics permit a variety of electronic devices and non-invasive sensors to be affixed to a thin and flexible substrate, enabling designers to integrate sensors, microcontrollers, wireless connectivity and batteries into durable and connected devices.

Whether in a clinical or home setting, this enables far more comprehensive patient monitoring. Adding enhanced capabilities to lightweight and flexible skin patches allows patients to go about their day while they or their healthcare provider monitor vital signs or activity non-invasively. There is tremendous potential for this flexibility to improve patient monitoring and make it simpler, more comfortable and more accessible.

Evolving needs

During the Covid-19 pandemic, the need for hospitals and clinics to monitor patients remotely became clear. This c did more than allow doctors to track their patients’ vital signs while maintaining social distancing – it also helped address hospital overcrowding and assisted in alleviating staffing issues. Smart skin patches have emerged as a lightweight, comfortable and portable method of monitoring patients both inside and outside a healthcare facility.

The market for home health monitoring is flourishing as well. With smart skin patches, home users can monitor their heart activity, temperature and muscle health. These devices can also be used for monitoring sleep and brainwave activity, making their low profile and light weight especially helpful. In addition, skin patches are increasingly popular for femtech applications such as pregnancy monitoring.

Smart skin patches all use flexible printed circuit technology and safe skin contacting adhesive but their design architecture varies depending on the application. Each skin patch is customised and, depending on the need, can be disposable or reusable. Disposable and one-time-use skin patches have a flexible substrate, usually polyethylene terephthalate (PET), with the electronics fixed directly to the substrate. In reusable patches, the electronics are mounted inside a removable “puck” housing that mechanically and electrically connects to the substrate. The electronic components are reusable and only the electrodes in contact with the skin are disposable, reducing waste. This can, however, add logistics challenges and costs for the refurbishing process in some cases.

Opportunities and challenges

Designers of monitoring systems can leverage a wide range of smart skin patch feature options and they can include various types of electronic devices, including temperature sensors, chemical sensors, electrodes and even optical sensors. The skin patch can also include a battery, a microcontroller and a radio frequency (RF) antenna to maintain a wireless connection to the network.

These are the physical building blocks of the system, and to achieve a specific purpose designers can mix, match and customise them to meet performance targets. Different combinations of sensors and other devices can work with sophisticated software to non-invasively paint a picture of a patient’s condition or vital signs.

Unfortunately, system reliability requires several different engineering disciplines. Material science, for example, is vital to ensure the substrate can accommodate the expected wear, yet also provide a secure anchor for the electronic components. The type of conductive paste and hydrogel must meet the system’s requirements for manufacturability, shelf life and performance. Electronic components also need to operate reliably during the expected lifetime of the product and robust testing and validation are necessary to ensure product performance and support regulatory compliance.

Concept to production

Creating a smart skin patch means assembling multiple puzzle pieces to create a complete system. Collaborating with a company with decades of experience in this field is crucial. At Molex, several engineering disciplines work together to achieve a unified goal – hybrid printed electronics design, material science, wireless connectivity,  sensor integration, prototyping, testing and validation, production and packaging.

Involving Molex engineers from the earliest stages of the design process helps ensure the product meets performance specifications and manufacturing requirements. In addition to engineering expertise, Molex also offers global manufacturing capabilities to reduce supply chain risks and speed time to market.

The need for smart skin patches to improve patient wellness and outcomes is enormous and continues to grow. The medical expertise and collaborative design approach of Molex, coupled with a diversified supply chain, high-volume production capabilities and regulatory compliance experience enables us to support the full development of customised smart skin patch solutions.

Molex will be exhibiting at the Future of Electronics show taking place in Berlin, Germany, from October 17-18. Full details can be found here.

www.molex.com