Mono-layered graphene tattoos are a peculiar yet unique application used in personalised healthcare. Often used for monitoring different electrophysiological signals in human beings. Often they face a major issue, their impermeability to sweat and lack of reproducibility. A group of scientists have come up with improved and updated Graphene Electronic Tattoos (GETs) which have enhanced performance, are more breathable and are more robust with aggrandised electronic performance.
The use of metal and silicon-based biomedical devices has been the norm in the medical industry, but now they are being phased out persistently by extremely lightweight, almost skin-like materials with relatively softer textures which do not interfere with their impedance. Such bioelectronic devices are developed by systematically piling up multiple layers of graphene. The graphene monolayers piled up within a single tattoo can greatly improve electronic properties. By employing this structure, piling up the tattoos with multilayered graphene resulted in a reduction of skin impedance by two and a half times, a decrease in sheet resistance of up to three and a half times, and a reduction in standard deviation by up to 5 times over the prior generations.
The first iterations of the GETs demonstrated approximately 85 per cent clarity and the capability to cling to the skin through van der Waals forces. Furthermore, the GETs showed about 40 per cent stretchability allowing an undisturbed facile application on the skin, deterring strain-induced performance artefacts and motion-induced noise. Although the initial designs had satisfactory results they lacked in some crucial aspects, which were sheet resistance, interface resistance, and inaccuracies in the optimisation of the water vapour transmission rate of GETs.
GETs 2.0, an improvement over the first version was fabricated with a trilayered design, which showed an improvement in sheet resistance by 3.5 times, and an enhancement in the interface impedance by up to 2.5 times when compared to the monolayered fabrications. Furthermore, GETs 2.0 was enhanced with micro holes in the topographical structure to improve breathability and significantly improved multi-planar skin contact, thus emboldening the path for the future of the next generation of hybrid wearable bioelectronics.
The scientific publication can be read here.