Testing and analysis of nanoparticles-based textrodes for physiological signals

Abstract

The different kinds of electrodes to monitor the physiological parameters like heart rate, respiration rate, blood pressure, temperature etc. have become inevitable in the healthcare sector. The use of surface electrodes may be allergic to the skin, and the glue used here gets dehydrated over some time. Moreover, surface degradation of electrodes leads to poor acquisition of signal. Hence, the present-day monitoring systems fail to provide a high level of comfort to the users. To make the continuous monitoring system to be more reliable, textile-based wearable electrodes (textrodes) for ECG measurement device is proposed. The fabric in the textile electrode must be conductive to acquire the biosignals. The textiles are made conductive by coating them with a silver (Ag) and copper (Cu) nanoparticles. The poly (3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT: PSS) solution is also used to make the fabric conductive. Both are blended at certain ratios to enhance better conductivity. Silver nanoparticles and copper nanoparticles are produced by chemical reduction and solution reduction methods respectively. In both processes, sodium borohydride is used as a reducing agent. The presence of Ag and Cu nanoparticles is confirmed by UV and XRD analysis. The obtained UV range for silver and copper nanoparticles are 405 nm and 545 nm respectively. The skin impedance of the commercially available disposable electrodes offers 4KΩ. Based on experimentation, PEDOT: PSS coated cotton fabric offers the lowest impedance; thereby low signal to noise ratio (SNR) is achieved while acquiring ECG signal in a real-time environment. Followed by PEDOT: PSS, Ag and Cu coated cotton fabrics offer better impedance and SNR. The application of textrodes can be expanded continuously to meet people’s activity where the electronic product is expected to be integrated with garments as so thin and lightweight.