Author(s): Lopes, Cláudia Jesus Ribeiro ; Fiedler, Patrique ; Rodrigues, Marco S. ; Borges, Joel ; Bertollo, Maurizio ; Alves, Eduardo ; Barradas, Nuno Pessoa ; Comani, Silvia ; Haueisen, Jens ; Vaz, F.
Date: 2021
Persistent ID: http://hdl.handle.net/1822/76716
Origin: RepositóriUM - Universidade do Minho
Subject(s): Thin-films; Binary intermetallic systems; Ti–Me dry electrodes; Polymers; Electrode–skin impedance; Biopotential measurement; Science & Technology
In a new era for digital health, dry electrodes for biopotential measurement enable the monitoring of essential vital functions outside of specialized healthcare centers. In this paper, a new type of nanostructured titanium-based thin film is proposed, revealing improved biopotential sensing performance and overcoming several of the limitations of conventional gel-based electrodes such as reusability, durability, biocompatibility, and comfort. The thin films were deposited on stainless steel (SS) discs and polyurethane (PU) substrates to be used as dry electrodes, for non-invasive monitoring of body surface biopotentials. Four different Ti–Me (Me = Al, Cu, Ag, or Au) metallic binary systems were prepared by magnetron sputtering. The morphology of the resulting Ti–Me systems was found to be dependent on the chemical composition of the films, specifically on the type and amount of Me. The existence of crystalline intermetallic phases or glassy amorphous structures also revealed a strong influence on the morphological features developed by the different systems. The electrodes were tested in an in-vivo study on 20 volunteers during sports activity, allowing study of the application-specific characteristics of the dry electrodes, based on Ti–Me intermetallic thin films, and evaluation of the impact of the electrode–skin impedance on biopotential sensing. The electrode–skin impedance results support the reusability and the high degree of reliability of the Ti–Me dry electrodes. The Ti–Al films revealed the least performance as biopotential electrodes, while the Ti–Au system provided excellent results very close to the Ag/AgCl reference electrodes.
This work was supported by the European Regional Development Fund (ERDF) and by the European Union’s Seventh Framework Programme, grant number 610950; through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020), under Portugal 2020 in the framework of the NanoStim, grant number POCI-01-0247-FEDER-045908, and NanoID, grant number NORTE-01-0247-FEDER-046985 Projects; and the Free State of Thuringia grant number 2018 IZN 004.
