Science and Nature news
Bioinspired skin adhesives are a promising alternative to traditional glue-based patches for sticking medical devices to the skin. Many patches are chemical-based, and the chemicals in their glues can cause a range of side effects for the skin.
Inspired by the infundibulum and circumferential rim of the suckers of octopi, KAUST researchers have developed a way to rapidly and cheaply create medical patches that carry ‘adhesive miniaturized octopus-like suckers’ (AMOS). These patches are reusable, flexible, biocompatible, breathable, and can monitor vital signs.
The patches are attached with an electrode that monitors several types of biosignal.
Traditional glue-like skin adhesives, like medical tapes, can cause skin injuries due to their reactive materials. In contrast, bioinspired suction-based adhesives, which mimic the attachment methods of animals like octopuses, frogs, and geckos, generally adhere well to the skin. However, the standard techniques used to create these tiny structures are expensive and limit how much they can be customized, making them less versatile for widespread use.
3D printing has become crucial for improving skin-attachable devices as it allows for affordable and quick customization. While there has been progress in creating 3D-printable biomaterials for skin adhesives used in diagnostics and therapy, exploring the potential for 3D printing tiny, bioinspired adhesive structures has not been widely investigated.
In this study, scientists used a rapid hybrid 3D printing approach to create a permeable skin patch with adhesive miniaturized octopus-like suckers (AMOS). Their 3D printing technique, stereolithography, offered the precision required to make AMOS patches.
This method uses an ultraviolet laser to build up a resin mold containing tiny domes and wiggly lines. Then, they used that mold to create an AMOS patch from a biocompatible polymer called polydimethylsiloxane (PDMS), which has some inherent stickiness.
Scientists tested their patches (with different-sized suckers and various patterns) and found that 200 micrometer-wide suckers offered the most excellent adhesion. The patch’s wiggly grooves escape moisture from the skin, and the material becomes highly breathable.
Aljawharah A. Alsharif, a Ph.D. student under the supervision of El-Atab, said, “When the patch is lightly pressed onto the skin, the suckers create a vacuum, providing secure adhesion even under various skin conditions such as dry, wet, or hairy surfaces. This adhesion mode also enables the same patch to be reapplied repeatedly, making it useful for long-term health monitoring.”
For testing, scientists attached the patch to the hairy chest of a male volunteer while he cycled on an exercise bike. The purpose was 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,” noted scientists.
Alsharif said, “The versatility of the AMOS patch allows it to function effectively across different types of biosignal measurements simultaneously, demonstrating its broad applicability and efficiency in biomedical applications. It can also be reused multiple times without significant loss of adhesion.”
Scientists look forward to applying AMOS patches to other measurements, including temperature, glucose, and stress levels. Extensive clinical trials will validate its efficiency in real-world medical applications.
Journal Reference:
- Alsharif, A.A., Syed, A.M., Li, X., Alsharif, N.A., Lubineau, G. & El-Atab, N. Hybrid 3D printing of a nature-inspired flexible self-adhesive biopatch for multi-biosignal sensing. Advanced Functional Materials 2406341 (2024). DOI: 10.1002/adfm.202406341
