A Novel Electrode for Pasteless Ecg Monitoring

A dry bracelet electrode for electrocardiographic (ECG) signal monitoring was developed and successfully tested in human volunteers. The new electrode dispenses with the usual gel application and the previous skin preparation to monitor the signal. It was fabricated from a polyethylene tereftalate (PET) polymer sheet that was coated with a thin conductive titanium nitride (TiN) layer. As the direct sputtering of the TiN layer on the polymeric surface results in a poor adherence of the layer, a specific polymer activation treatment was developed, consisting of the polymer surface bombardment with alternate beams of argon and titanium ions. The adhesion tests and the SEM analysis of the coatings proved the success of the treatment. The TiN coating displays the fcc crystalline structure of the δ-TiN bulk material with a rough, pyramidal-like morphology. The electrochemical analysis that was carried out in a saline solution (to mimic the skin sweat contact) showed delamination of the film after prolonged contact with the saline solution.. The new electrode was tested against the classic gelled silver/silver chloride electrode (Ag/AgCl) and the ECG records proved to be very similar with both devices. The new bracelet electrode is ideal for monitoring in ambulatory conditions, as the usual abrasive skin preparation and the gel application may be skipped. It may be particularly suitable for longterm monitoring, where the prolonged contact with the gel paste often induces strong allergic reactions.