There is no single, specific treatment for a wound. Because they vary in type, severity, and location, each wound dressing must be designed and constructed to help heal that wound — whether it’s a cut, burn, sore, etc. — as well as prevent infection and reduce pain.
Similarly, the adhesives used for wound dressings must also be selected based on how each wound dressing is built and the environment in which it will perform.
An adhesive in a wound dressing product has two main goals: stick to human skin and be removed from that same skin. Sounds simple, but there’s a lot more involved that challenges flexible material converters.
Earlier this year, we covered the basics of wound dressings: what they are, pretreating a wound, and an extensive wound dressing selection chart. If you want to learn more about medical adhesive tape — types, applications, and finding the right converter — read this article.
Today’s blog post will focus on wound dressing adhesives; specifically, their purpose, importance, and challenges. Plus, these four critical considerations that converters use when selecting a wound dressing adhesive:
- The Application
- The Skin Type
- The Location
- The Length of Wear
Before we dive in, one basic aspect of wound dressings to keep in mind is that there are two main types: general purpose and specific purpose. General-purpose bandages, wraps, etc. are designed to handle a wide variety of common wounds.
Then there are specific purpose wound dressings; custom kits that medical professionals (doctors, surgeons, etc.) use during or as a result of surgical procedures on specific parts of the body. These uses require unique construction of the wound dressings themselves and specific grade adhesives, which leads into our first critical consideration: the application.
1. The Application
The wound dressing application drives everything. Consider these two very different examples. Inserting an intravenous (IV) catheter may require both a covering and a seal to prevent infection over several days. A small gash may need just a simple dressing to close the wound while holding an antibacterial medication in place; with replacement often to occur.
These two applications differ in size, complexity, function, placement … and adhesives! The entire application is different, although both are definitely “wound dressings.”
In general, wound dressings form a window around a square or circle containing a breathable wound dressing or a seal. Material selection (and the wound dressing’s construction) heavily depends on whether the application is breathable — designed to let oxygen in and allow moisture to evaporate from it — or if it’s designed to create a negative pressure seal.
Negative pressure wound therapy uses suction to create a seal that helps prevent infection, slowly drawing bacteria and other bodily fluids into a collection chamber. A battery or electric-powered pump applies suction through foam or gauze and achieves an airtight, waterproof seal. Some advanced wound dressings also pull samples, transferring fluids from the patient into devices for collection.
An adhesive needs the holding power to handle the suction and any activity of the patient throughout the duration of wear. Some adhesives are designed primarily to perform a certain function under certain environmental conditions. Of course, one type of adhesive may be applied in several different applications. It all depends on what the application needs.
2. The Skin Type
It’s no surprise that an infant’s skin differs from the skin of an adult or an elderly person. The adhesive must match the durability of the skin to adhere securely yet still prevent damage to the skin or cause the patient pain upon removal.
Most wound dressings are designed to be removed at regular intervals and replaced. This makes selecting an adhesive that much more important, especially on sensitive skin.
Silicone adhesives are soft and work well on sensitive skin applications because they stick well but are also easy to remove. Acrylic adhesives have slightly more aggressive adhesion, and rubber adhesives are the strongest and stay on the longest.
Although commonly used in food formulations as a thickening and gelling agent, hydrocolloids are used in the most advanced medical-grade adhesives. Within a hydrocolloid, particle molecules bind to water and to each other, suspending the liquid flow and solidifying it into a gel. This gel-like adhesive provides non-breathable adhesion to skin, trapping moisture under the surface and promoting healing in wound care products.
Very versatile and environmentally sensitive, a hydrogel is a polymer material that absorbs a large amount of fluid and is also conductive, so sensors can be built into the wound dressing itself. Although not an adhesive, hydrogel is used within wound dressings because it is both viscous and elastic (viscoelastic), adding comfort to sensitive skin.
Of course, all adhesives must meet ISO 10993-5:2009 standards for biological evaluation of medical devices, ensuring that human skin of all types is protected.
3. The Location
The wound dressing’s location on the body greatly determines what material is used and what type of adhesive is needed. For example, the human arm’s many bends and movements require the dressing to be conformable. So, a bandage for an elbow should use a medical adhesive transfer tape. Why? Because when a transfer tape is put on spandex, for instance, it remains stretchy.
Using a double-sided medical tape, for instance, on that same spandex removes its ability to stretch and conform. However, a wound on the chest (a relatively flat surface) remains much more stable.
Knowing that a product needs to be ultra-conformable prompts the use of specific adhesives, but the backing substrate doesn’t necessarily drive what adhesive is used. Adhering to polyurethane or non-woven backing can be done using just about any adhesive option.
4. The Length of Wear
Some wounds require immediate intervention and will soon need additional medical attention. An adhesive for this application is very temporary, only staying in place for an hour or two.
Other wounds need nothing more than time to heal, which can take a few days.
Still, other wounds require medical devices to be placed within them, and adhesives for these need to keep that wound dressing in place for up to 14 days.
For these longer-term applications, the adhesion level drops as skin cells naturally degrade and fluff off over that 2-week time period. However, if used for a 1-hour application, that same adhesive would be extremely painful to remove, no matter what skin type.
Mentioned earlier as an option for sensitive skin, hydrocolloids are designed to be applied for up to 14 days because, as time elapses, they physically absorb fluffed off skin cells which get absorbed into the adhesive.
When considering a wound dressing adhesive, in general, the 80/20 rule applies: 80 percent of the applications require a very similar adhesive, while 20 percent require unique or specialized adhesives.
Truth be told, a successful wound dressing relies more on construction than it does on the adhesive used. That’s why choosing the right flexible material converting partner is so important.
An experienced converter understands that the air’s moisture level can lead to bacteria growth that changes adhesion in medical products applied to human skin. Having ISO cleanroom certification prevents these particles in the air. Sterilization capabilities are also a universal must-have for wound dressings, although methods vary widely — from heat to steam to gas to radiation — with each affecting the adhesive in a different way.
When you partner with a 3M Preferred Converter of 3M Medical Materials and Technologies, you're assured of partnering with engineers who work to design adhesive components and products while navigating the FDA approval process. Their access to cutting edge materials, experience with high-end products, reasonable pricing, and overall industry leadership helps deliver the right solution for any wound dressing need.
Here at Strouse, our Sample Express rapid prototype delivery system puts samples in the hands of engineers and designers who can get a sample die-cut and weigh the performance/cost issues to determine the best adhesive for any particular wound dressing.