Textile-Based Sensors for Biosignal Detection and Monitoring

Abstract

Biosignals often have to be detected in sports or for medical reasons. Typical biosignals are pulse and ECG (electrocardiogram), breathing, blood pressure, skin temperature, oxygen saturation, bioimpedance, etc. Typically, scientists attempt to measure these biosignals noninvasively, i.e., with electrodes or other sensors, detecting electric signals, measuring optical or chemical information. While short-time measurements or monitoring of patients in a hospital can be performed by systems based on common rigid electrodes, usually containing a large amount of wiring, long-term measurements on mobile patients or athletes necessitate other equipment. Here, textile-based sensors and textile-integrated data connections are preferred to avoid skin irritations and other unnecessary limitations of the monitored person. In this review, we give an overview of recent progress in textile-based electrodes for electrical measurements and new developments in textile-based chemical and other sensors for detection and monitoring of biosignals.

Keywords: ECG; EMG; elderly; firefighters; health condition; health status; sportsman; sweat.

Figure 1

Typical features of an ECG signal. From Reference [18], originally published under a CC-BY license.

Figure 2

Production of flocked electrodes and wires with the electrostatic flocking technology. (a) Scheme of the production, with Ag-plated fivers being flocked on the textile with an adhesive paste; (b) photograph of electrodes and wires on a textile fabric; (c) cross-section view along the A-A′ line (Figure 2b) of a flocked electrode; and (d) flocked electrode in contact with the skin. From Reference [29], originally published under a CC-BY license.

Figure 3

Three-layer piezoresistive array of 13 × 15 elements at the crossings between column and row conductors. From Reference [66], originally published under a CC-BY license.

Figure 4

Electrode preparation in varied (a) electrode diameters and varied (b) pattern reduction rate (PRR). (c) positioning of the electroded on the rectus femoris. From Reference [79], originally published under a CC-BY license.

Figure 5

Equivalent circuit model for the skin–electrode interface. From Reference [83], originally published under a CC-BY license.

Figure 6

Cross-sectional scheme of thermistor encapsulated in a yarn comprising polymer resin, packing fibers and knitted sheath. The carrier yarn within the resin encapsulation improves the tensile strength of the final yarn. From Reference [105], originally published under a CC-BY license.

Figure 7

Scheme of the moisture-detecting underpants. From Reference [119], originally published under a CC-BY license.