The healthcare world today is one that is rapidly changing and ever-evolving. Several dynamics are driving these changes, including an aging population, the increasing prevalence of chronic diseases, and pressure on healthcare providers to deliver high-quality medical care at the lowest cost possible. Factors like these are putting pressure on an already strained healthcare system, fueling the need for medical solutions that are aimed at enhancing efficiencies, reducing costs, and helping improve patient care, the patient experience, and patient satisfaction.
For medical device manufacturers, this means healthcare providers are looking for new, more advanced solutions in every patient setting — from hospital to home — that will help them do their jobs better, and leave their patients feeling satisfied and pleased with their care.
For example, when looking at the medical information technology market, recent advancements in electronic medical records and barcode medication scanning are trending, bringing added convenience to healthcare providers when charting patient information, delivering medication, and more. Technologies like these are not only improving the accuracy of care — such as having instant access to a patient’s most recent medication dosage — but also leave patients feeling better informed about their care and, thus, more satisfied with the care they are receiving.
Similarly, the use of wearable medical sensors in at-home healthcare applications is another recent trend that has been taking off. According to Grand View Research, the global market for wearable medical devices is expected to reach $27.8 billion by 2022. That may seem like a hefty prediction, but consider this: the median age of the U.S. population increased from 35.3 in 2000 to 37.2 in 2010, according to the 2010 U.S. Census Bureau brief. The baby boomer segment continues to age, life expectancies are increasing, and health awareness is increasing. Chronic diseases are soon expected to become the world’s leading cause of death and disability, accounting for nearly 75 percent of deaths by 2020, according to a United Nations Division for Social Policy and Development, Department of Economic and Social Affairs report. Remote patient monitoring is projected to exhibit growth of more than 25 percent in the next seven years. All of these factors create additional demand for wearable medical devices.
With projected growth and opportunity in the wearable medical sensor device manufacturing business, manufacturers, device designers, and converters are aiming to create wearable sensor solutions that will deliver superior performance and added convenience, as well as enhanced patient comfort, to better meet the many needs of healthcare providers today.
Wearable Medical Sensors: A Brief Overview
Wearable medical sensors are worn by a patient and come in many forms. They are designed to monitor and wirelessly transmit physiologic information from a patient to a patient’s physician. The physician can receive the information provided by the wearable medical sensor via their computer, smartphone, or other connected device.
With features that make them easy for patients to use, wearable medical sensors operate in a manner similar to many devices that track fitness levels. For example, they allow long-term, continuous monitoring of physiologic information such as heart rate, blood pressure, blood oxygen saturation, insulin levels, respiration, and more. Additionally, they can also provide an accurate assessment of a patient’s health status.
Wearable medical sensors are most commonly used for at-home applications, although they are also used in various settings where medical monitoring or testing is required. The unique advantages offered by at-home wearable medical sensor technology are appealing to healthcare providers and patients for numerous reasons. For example, sensors designed for use at home can collect and transmit data to physicians that would otherwise be cost-prohibitive when conducted in a clinical setting.
In addition to reducing costs for both providers and patients, innovations in medical devices that can be worn at home can enhance the efficiency of patient health information collection for healthcare providers, and promote usability among patients since wearable devices minimally impact a patient’s daily life and free them from frequent physician visits. And, while there are various types of wearable medical devices out there — from watches to shoe insoles — those that directly adhere to a patient’s skin continue to emerge as one of the more popular choices for healthcare providers and patients.
Multilayer, Direct-to-Skin PSA Solutions
High-quality, skin-friendly pressure-sensitive adhesives (PSAs) have been used in medical device-to-skin applications for decades, and PSA suppliers have been working diligently to create medical-grade adhesives specifically for these applications. In fact, skin-related applications have shaped the way medical-grade adhesives are designed — creating functionally diverse adhesives based on factors such as patient age, gender, ethnicity, physical environment, length of wear, and more. With at-home wearable medical sensor applications that adhere directly to a patient’s skin, variables such as physical movement, sweating, showering, or changes in body heat, for example, are important factors to consider when selecting an adhesive.
So, what does a successful wearable medical sensor PSA look like? In the most basic terms, it’s multilayered and fully customizable. It maintains three of the most important priorities for the growing wearable sensor trend: performance, convenience, and patient comfort.
Medical-grade adhesives for wearable medical sensors often come in varying levels of adhesion — from low or soft adhesion levels, to high- or extra-strength adhesion levels. The right adhesive systems should provide customers with the flexibility to choose the adhesive strength, quick tack, peel strength from skin, shear strength, and removability necessary to meet their customized needs.
To create the right system, one must carefully consider the proper combination of substrate and adhesive to create the desired moisture vapor transition rate (MVTR). If the medical sensor needs to offer high levels of breathability, the adhesive must be highly breathable.
With recent advancements in adhesives technology, some of the most ideal adhesives for wearable medical sensor applications are those that are solvent- and latex-free, and made with 100 percent solids technology. This adhesive technology is known to provide excellent long-term adhesion up to 14 days, as well as ultraclean removability without irritation; therefore, patients don’t have to sacrifice comfort for performance.
And, unlike relatively expensive solvent-coated acrylic adhesives, 100 percent solids-coated acrylic adhesives can be produced much more cost-effectively since the manufacturing process for these adhesives does not require energy-consuming drying ovens or challenging cleanup. Additionally, 100 percent solids adhesives are inert, non-outgassing, nonfluorescing, nonmigratory, and usable in applications requiring very precise deposition control — also making them a confident, cost-effective solution for wearable medical sensors. It is also extremely flexible and can be coated on a wide variety of materials, including foams, films, or fabrics, as single-coated products or double-coated products.
There are several considerations manufacturers, design engineers, and converters should make when pairing the adhesive with an ideal product material. Each material has its own unique characteristics and some are more ideal than others for certain applications. Some of the most common product constructions for wearable device sensors include transparent films or film tapes, foam tapes, and nonwoven tapes. Below are a few important highlights about each of these substrates.
Transparent films or film tapes – Transparent films or film tapes provide a durable, see-through finish for wearable device sensors requiring transparency. Depending on the film construction, films can offer important performance characteristics such as conformability, breathability, good oxygen and moisture vapor exchange, waterproof and fluid-barrier properties, and impermeability to bacteria and viruses. Common film materials include polyurethane, polyethylene, and polyester, and include paper casting sheets and liners, which are well suited to accommodate different converting methods. Films are known as a versatile material and can be coated with varying adhesive coat-weights depending on the level of adhesion and moisture vapor transmission rates necessary for the application.
Foam tapes – Foam tapes are ideal for wearable sensor applications that necessitate sustained skin contact. They are designed to hold tubes and wires in place more comfortably, in addition to providing enhanced stability for sensors. Foam tapes are also known for their excellent adhesion and clean removability.
Nonwoven tapes – Key performance attributes of non-woven tapes include breathability, good oxygen and moisture vapor rate exchange, elasticity, and conformability. Nonwoven tapes are designed to enhance both performance and patient comfort. They are often constructed of materials such as spun-laced polyester or elastic fabric, for example, and are typically recommended for electromedical and bandage-type applications, making them ideal for wearable device sensors.
Selecting the Right PSA
When evaluating a PSA for a wearable sensor application, manufacturers, design engineers, and converters should not only consider the composition of the PSA and how the layers of the PSA best match the specific wearable sensor application, but should also consider the supplier providing the PSA.
Customization is key. With medical-grade adhesives, customization should be one of the most important qualifications for device manufacturers, designers, and converters when choosing a PSA supplier. Medical-grade adhesives are not typically an off-the-shelf product, and an ideal PSA supplier will have product customization at the top of the company’s list of offerings.
To meet the demanding needs of medical-grade adhesive products, a supplier should offer significant flexibility when it comes to custom-matching adhesives to foams, films, fabrics, and more. A progressive supplier can contribute to long-term success with product customization. The best adhesives suppliers are those who are not limited to stock products, but who partner to develop custom solutions appropriate for their customer’s applications.
Manufacturing processes are critical. Some of the most important traits to look for when it comes to direct-to-skin medical adhesives are securement to the skin, MVTR and fluid-barrier abilities, clean and smooth removability, and skin compatibility, among others. Other important qualities include latex-free and hypoallergenic properties.
To achieve these varying medical-grade adhesive properties, adhesive manufacturers will pay close attention to the quality of each individual component used, both before mixing the components and again after mixing. A good supplier will also conduct quality inspections before delivering the mixed components to the coater, throughout the coating process, and once again during the manufacturing slitting stage.
To ensure complete control over the entire manufacturing process, an ideal adhesives manufacturer will have in-house mixing and reactive extrusion and compounding capabilities. They will also follow strict process guidelines, such as current Good Manufacturing Practice (cGMP) guidelines, and ensure their direct-skin-contact PSAs meet outlined International Organization for Standardization (ISO) and Food and Drug Administration (FDA) guidelines.
Abundant Opportunity on the Horizon
The dynamics driving change in the world of healthcare today, coupled with the explosive projected growth of the wearable medical sensor market and the increasing popularity of direct-to-skin wearable sensor products, present endless opportunity for device manufacturers, design engineers, and converters in the wearable medical sensor business. With customized, multilayered PSAs — and a trusted PSA supplier partner at their side — these key medical device players can deliver healthcare providers and their patients high-performing wearable medical sensors that are certain to deliver sought-after product benefits such as convenience and comfort.
This article was written by Janet Page, Marketing Manager at Mactac Performance Adhesives, Stow, OH. For more information, Click Here .