New reusable medical patch with octopus-shaped suckers that adhere to the skin can track a number of vital signs and perhaps stop the skin irritations, blisters, rips, and tension injuries brought on by conventional adhesive patches.

“The patch is designed for easy removal without causing discomfort or pain, unlike conventional glue-based patches,” says Nazek El-Atab, who led the team that developed it.  “Our goal is to develop a comprehensive, versatile, skin-attachable device that can revolutionize wearable health monitoring and diagnostic technologies.”

Medical professionals frequently use adhesive patches to attach medical equipment to patients. These devices could be used to give essential medications through the skin or to record things like muscle reaction or pulse rate. Many patches rely on chemical adhesives; however, these glues can produce a range of negative effects for the skin, reports Aljawharah Alsharif in KAUST Discovery.

The round suckers that octopuses have on their limbs have inspired KAUST researchers to produce a quick and inexpensive method of producing medical patches that contain "adhesive miniaturized octopus-like suckers" (AMOS). The biocompatible, breathable, flexible patches have an electrode that can track many types of biosignal.

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“Previous bioinspired suction-based adhesives have suffered primarily from limited manufacturing flexibility and versatility due to traditional nano-/microfabrication techniques,” explains Aljawharah A. Alsharif, a Ph.D. student under the supervision of El-Atab.

“Other bio-inspired patches that adhere using suction mechanisms tend to face challenges when it comes to manufacturing: traditional nano-/microfabrication techniques limit the required manufacturing flexibility and versatility to produce them. Typically, these adhesives feature tiny hollows or ridges measured in millionths or even billionths of a meter and so fabricating materials with these finely detailed structures can be expensive. Also, they may only be effective on certain types of skin surface.

According to Alsharif, the AMOS patch uses a quick hybrid 3D printing method to overcome these restrictions. The researchers discovered that stereolithography, a method of 3D printing, might provide the accuracy required to create the AMOS patches. The process involves precisely building up a resin mold with small domes and wavy lines using an ultraviolet laser. Subsequently, they employed that mold to fabricate an AMOS patch using polydimethylsiloxane (PDMS), a biocompatible polymer with a naturally occurring stickiness.

They discovered that patches with 200 micrometer-wide suckers provided the best adherence after testing patches with varied sucker sizes and patterns. In the meantime, the material of the patch is very breathable because of its wiggly grooves, which aid in allowing moisture to escape from the skin. According to Alsharif, "the suckers in the patch create a vacuum when it is lightly pressed on the skin, providing secure adhesion even under various skin conditions such as dry, wet, or hairy surfaces." The same patch can be applied again and again thanks to this technique of adhesion, which makes it helpful for long-term health monitoring.

The researchers fitted the patch with electrodes, attached it to the hairy chest of a male volunteer while he cycled on an exercise bike, and used the device to monitor the subject’s electrocardiogram (ECG) signals. The same patch could also be placed on different parts of the body to record electromyograms (EMG) — which measure muscle response — and electrooculograms (EOG) to monitor eye movements.