Electrodes placed on the skin, cutaneous electrodes, are used to monitor the electrical activity of specific organs such as the brain (electroencephalography, EEG), the heart (electrocardiography, ECG) or particular muscles (electromyography, EMG). The quality of the electrophysiological recording depends on the impedance of the interface between the skin of the patient and the cutaneous electrode. Standard medical procedures use cutaneous electrodes based on silver / silver chloride (Ag/AgCl) conductive layers that require the application of a water-based electrolyte (hydrogel) to reduce impedance across the electrode and the skin interface.
This has a number of limitations: the aqueous hydrogel dries out after several hours causing the loss of electrophysiological signal, the water evaporation causes short circuits and refilling the aqueous hydrogel is time-consuming and discomfortable.
This project addresses these problems associated with the use of water-based electrolytes through the development of a new generation of gels, bioconductive iongels.
The healthcare sector needs a new generation of materials with soft mechanical properties and superior ionic/electrical conductivity in order to interface between human tissue and electronics. For example, as discussed above, the performance of commercial, widely used cutaneous electrodes is limited due to the poor stability of the electronic-skin interface. Consequently, this project is potentially high social impact and it will lead to the development of new materials to improve the electronic-skin interface ensuring the adequate acquisition of electrical signals to monitor the activity of an organ. Higher- quality data will enable the early detection of different diseases related to the heart, brain or muscles, such as arrhythmias, epilepsy or muscular problems.
To overcome problems associated with the use of water-based electrolytes in electrophysiological diagnostic procedures, this project aims to develop innovative materials: iongels, ionic liquid integrated into a polymer network. Due to the negligible vapor pressure of ionic liquids, long-term recordings can be made without the problem of evaporation. Moreover, the iongel can decrease impedance at the interface with a patient’s skin, thus improving the stability of the electronic-skin interface. The iongels have been fabricated ensuring good adhesion, biocompatibility with skin, conductivity and biodegradability.
Overall, the focus of this project is to create a new generation of bioconductive iongels and determine the potential of these state-of-the-art materials for improving the performance and lifetime of electrical health monitoring systems.
