Medical Wearables Rely on Smart Adhesive Selection

    Medical wearables are advancing by leaps and bounds, using advanced electronics to monitor patients and adhesive skin patches to deliver medications transdermally. But the one thing all these devices have in common is the need for adhesives to affix them to skin and to bond components together. Terminologically, the former would be defined as a skin contact layer while the latter is called a tie-layer, and this distinction would have a profound influence on the choice of adhesives.

    Moisture management is another important consideration. Adhesive materials help to keep patients comfortable by dealing with sweat. Moisture vapor transmission through tiny holes in the adhesive represents one strategy, while others keep clamminess at bay through moisture absorption. Materials would also influence the efficacy of adhesives in moisture management. For example, if a porous, breathable adhesive is used to bond materials, it will not function as intended if the materials chosen lack porosity.

 Adhesives manufacturers have developed vapor-transmission adhesive products ranging from acrylic adhesives to single or double-sided tapes. When the device itself does not allow for breathability, a hypercolloid gel layer between the device and the skin-contact adhesive provides a moisture management option. Patient comfort is always important, and when skin is damaged or delicate, silicone-based adhesive gels provide a gentle solution. Whatever the adhesive choice, the device must adhere to skin and yet be able to peel away without discomfort to the wearer.

    Adhesive choices will vary depending on the area of the body where the device will be worn. Areas where the skin is flexible will require adhesives that can flex with the skin, while areas where the skin is flat and tight would not require the same degree of flexibility.

   Finally, biocompatibility is an essential property when choosing adhesives for wearable devices. Extensive tests determine whether adhesives have any toxic effects and whether they may cause skin irritations. Due diligence throughout the value chain and adherence to the highest standards provide the final ingredients that assure us of safe, biocompatible, and comfortable wearable medical devices.