TIBI E-skin patch provides advanced healthcare monitoring

Developed at the Terasaki Institute for Biomedical Innovation (TIBI), the electronic skin (E-skin) patch is said to provide simultaneous, continuous monitoring of multiple bodily parameters while also providing temperature-moisture management and breathability.

Electronic skin patches monitor bodily physiological and chemical indicators of health. Placed directly onto skin, these monitors measure factors including body motions and temperature, skin hydration, various metabolic biomarkers, and brain and heart functionality via electroencephalograms and electrocardiograms respectively.

A typical skin-sensing patch consists of a sensor layer, which converts physical information into electrical signals, positioned on top of a flexible, stretchable substrate layer that is placed on the subject’s skin and is resistant to mechanical deformation.

According to TIBI, a number of current substrates have mechanical and biological incompatibilities, plus poor breathability, which hamper multi-sensing ability and can result in skin irritation and inflammation, especially with long-term use. Moreover, most of the current substrates cannot be recycled or disposed of in an environmentally friendly way.

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The TIBI researchers have addressed these problems by the development of a novel gelatine-based, highly porous substrate. By choosing to use gelatine methacryloyl (GelMA) to fabricate their substrate, they were able to meet the needs for biocompatibility, biodegradation, self-adhesion, and tissue-like mechanical properties. Challenges arose in fulfilling the need for breathability and moisture control, TIBI said.

Permeability can be achieved in GelMA by rendering it into a porous aerogel form, but the resultant aerogel is brittle, making it unsuitable for skin-sensing substrates. The TIBI researchers addressed this by studying the effects of cryofreezing on GelMA flexibility and using this information to develop a novel method for overcoming the brittleness of GelMA aerogels.

The method enabled the creation of a GelMA aerogel that is flexible, breathable, ultralight, and moisture/air-permeable, due to its highly uniform and interconnected pores and their potential for three-dimensional capillary action.

The substrate’s enhanced capabilities also enabled the ability to screen-print integrated multifunctional sensors onto the substrate, which could then be placed on the skin to simultaneously stimulate sweat excretion and extraction of interstitial fluid just below the skin surface. This allows the continuous and multifunctional monitoring of such bodily parameters as skin temperature and hydration levels, electro-cardiac measurements, and metabolic markers such as glucose, alcohol, and lactic acid.

These functions were validated using the new E-skin patch in tests measuring the effects of glucose and alcohol-containing diets on subjects performing strenuous exercise. When comparing the results against various individual commercial measurement devices, there was good correlation.

Further tests validated the new biodegradable E-skin’s flexibility, thermal cooling abilities, and fluid absorption over conventional brittle aerogel substrates while demonstrating biocompatibility and biodegradation without any skin irritation.

The team at TIBI said the multi-sensing device would provide a more accurate, real-time patient physiological profile, which is particularly beneficial for patients with several interrelated health conditions, such as those with insulin-dependent diabetes.

“The advancements described here pave the way for producing next-generation electronic skin devices,” said Ali Khademhosseini, Ph.D., TIBI’s director and CEO. “They will be valuable tools in healthcare management, offering the best in accurate, real-time monitoring for real-life situations.”