Silicone Advances Open Doors for New Wound Care and Wearables Development

Silicone medical adhesives, known for their gentle release from fragile skin, have been the gold standard for many advanced wound care and medical device applications. Their use is widespread, from attaching breathing tubes to vulnerable infants to treating pressure ulcers in elder care. Now, these materials can be considered for a broader range of uses thanks to recent research, development, and manufacturing advances.

Market Forces Spurring Silicone R&D
As healthcare providers face continued pressure to lower costs, they are seeking devices to help them meet both patient care and economic objectives. When it’s possible to do so, healthcare systems are moving care delivery out of hospitals and clinics and closer to the patient, such as through remote and in-home services. This lowers costs, especially when the patient can self-care or receive care from family members or friends rather than professional caregivers. The healthcare industry is examining new medical devices, materials, and strategies to significantly reduce costs in the overall system.

For skin-worn devices such as wound care dressings and diagnostic wearables, extended wear times help meet these goals. Silicones are one of the more expensive types of medical-grade adhesives. If they can be used in devices that last longer, however, their economic value is more compelling. Healthcare institutions can purchase fewer devices if patients need fewer changes, and insurers have lower reimbursement costs when patients require fewer clinic visits and skilled home healthcare providers.

Recent Silicone Advances
Lower Coat Weights
Some new soft silicone adhesive (SSA) materials are made with lower coat weights. In their earliest days, silicones were known for their thick, gel-like consistency. Used in wound-care dressings, SSA skin contact layer materials easily peel away when the dressing is pulled up from the patient’s skin. Today, adhesive materials suppliers are exploring ways to deliver an acceptable level of dressing adhesion with easy, atraumatic removal with a thinner coating of silicone. For example, Avery Dennison Medical offers a new duolaminate/trilaminate medical tape with an SSA coat weight of 100 grams per square meter (GSM). For comparison, many SSA materials have coat weights ranging from 150 GSM to 300 GSM.

Higher Tack Silicones
An adhesive’s tack level is a key variable in determining its hold strength. Good tack strength is required to securely hold relatively heavy devices or to attach devices for extended wear times. Adequate adhesive tack also gives devices some repositionability. The latest silicone R&D has yielded SSA with higher tack for increased skin adhesion while remaining gentle on removal.

Silicones with Greater Breathability
Moisture management is crucial for patient comfort in body-worn medical devices such as wound-care dressings and wearables. Silicones are inherently hydrophobic and have not been the adhesive of choice for device applications involving high exposure to water and perspiration because their adhesion can be limited in these conditions. However, when combined with the right additives, silicone adhesive materials can be more hydrophilic or capable of vapor transmission. Silicones blended with additives offer a simpler moisture management approach than perforation, which also is effective but adds manufacturing complexity and cost.

New Silicone Adhesive Applications
How can patients benefit from these silicone material advances? Following are a few examples of applications.

Wound Care Dressings
The new generation of SSA materials has multiple wound-care applications beyond the typical silicone sweet spot. For example, higher-tack silicones can now be considered to secure dressings for longer wear times. They also have the strength to hold in place super-absorbent wound-care devices, which become heavier during patient use. Both factors contribute toward less frequent dressing changes.

Short-Term Wearable Devices
Wearable devices have been the domain of highly breathable materials, capable of managing moisture while adhering securely to the end user. Device developers are focused on providing patients with the ultimate in comfort, including easy removal. New SSA with built-in moisture management capabilities and better tack offer a solution for wearables that need to be safe, remain secure for a short wear time, and then peel away painlessly.

Electroconductive Monitoring Devices
Silicone adhesives present an alternative to hydrogels for electroconductive monitors, such as those attached to the skin for electrocardiograms and similar studies. SSA-based monitoring pads do not dry out as quickly as water-based pads and thus offer a longer shelf life. This helps healthcare institutions simplify procurement and save costs in the long run.

Personal Protective Equipment (PPE)
Soft silicone gel adhesives are used to create the perimeter seal for strapless N95 filtering facepiece respirators (FFR). These PPE devices, which adhere directly to the face, are an alternative to N95 FFR styles that must press tightly against the face, held on with straps. Those FFR have caused skin trauma for some healthcare providers during the COVID-19 pandemic. When the skin-contact layer contains silicone adhesive, these new self-adhesive N95 FFR offer a soft, airtight hold and can be repositioned.

Putting the Pieces Together
There are exciting, incremental advances in silicone adhesives, but as with many medical device developments, there rarely is a one-size-fits-all solution. Unique patient needs require a carefully nuanced adhesive material solution for the best care experience. What works for one disease or chronic condition might not work for another.

Success requires collaboration between supply chain partners as well as interdisciplinary cooperation within every organization. For example, some of the SSA advances described in this article have required extensive project planning, iteration, compromises, and new approaches between R&D and manufacturing teams. In some cases, adhesives specialists and their raw material suppliers partner to co-develop customized adhesive solutions to meet end customer requirements. Sometimes, manufacturing teams help researchers reverse engineer product concepts to make them more amenable for high-speed production lines. There are also situations where novel solutions emerge only after project teams step away from the original course of action and look at the end goal anew.

By leveraging strengths within their teams and across the supply chain, medical material suppliers are developing innovative silicone adhesives to make a meaningful improvement in patient care.