A Sticky Situation – The Use of Adhesive Tapes in Diagnostic Tests

Point-of-care (POC) diagnostics are a rapidly growing technology allowing for the effective and efficient delivery of healthcare. The demand for faster analyses and results have led to the development of more sophisticated diagnostic tools; however, the fundamentals of the design and development of such medical devices remains unchanged.

One critical point to consider when developing a POC device is material selection including the adhesive used to laminate the layers that may be incorporated within the design. Adhesive tapes are commonly used in the manufacture of medical devices. They are lightweight, offer an invisible bond and have high performance characteristics that make them an ideal component in a device. Nevertheless, these characteristics and the way the adhesive interacts with other components directly imparts on the performance of the device.

There are many categories of adhesive available (e.g. silicone, acrylate, hydrocolloid, and synthetic based rubber) and within each type there are varying configurations (transfer adhesive, single coated, and double coated). With such a variety on offer, testing of the selected adhesive against the intended substrate becomes imperative to ensure it is fit for purpose.

Typical measurements that are commonly used in the testing of adhesive tapes include:

• Tack – the measure of the adhesive’s ability to adhere quickly to the substrate
• Peel – the measure of the adhesive’s ability to resist removal from the substrate by peeling
• Shear – the measure of the adhesive’s ability to remain in place on the substrate when a shearing force is applied

Adhesive bonds can typically undergo two types of failure; adhesive and cohesive failure. An adhesive failure occurs between the substrate and the adhesive whereas a cohesive failure is an internal failure of the adhesive to adhesive bonding. Any adhesive failures within a device can have detrimental effects on the system’s performance and accuracy/reliability hence the reason material testing is of paramount importance when developing point of care medical devices.

Rigorous design practice, coupled with sound material choices, will pave the way towards successful point of care design with organisations involved in the development of such diagnostic devices are at the forefront of the advancement of better diagnosis, monitoring, and management of diseases.