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Huang et al. Soft Sci 2024;4:40 https://dx.doi.org/10.20517/ss.2024.37 Page 23 of 35

the TENG in the upper left corner of the mattress when experiencing discomfort, thereby alerting family
members or healthcare professionals [Figure 9E]. These advancements carry significant implications for
remote healthcare.

However, multi-layered electronic fabrics can increase the weight of the detection system. Recently, the
same group optimized the textile electronics. They first prepared a single functional fiber, and then multiple
fibers were woven into a black textile substrate with a serpentine structure design, ultimately creating a
single-layer, ultra-soft intelligent bedsheet [Figure 9F]. The operation of the monitoring system is shown in
Figure 9G. Similar to their previous study, the pressure signals generated by each sensing unit are
independently addressable and can be recorded through a customized multi-channel data acquisition
circuit. After analog-to-digital conversion, the electric signals are transmitted to a mobile terminal via
Bluetooth. The real-time images of sleep postures and various physiological signals are shown on mobile
terminal displays.

Furthermore, the group also designed an obstructive sleep apnea-hypopnea syndrome monitoring and
intervention system and demonstrated its reliability [Figure 9H]. In cases where the apnea duration exceeds
a predetermined threshold, an alarm is activated immediately [Figure 9I]. Compared with their previous
study, this monitoring system has demonstrated advancements in enhancing monitoring accuracy,
broadening the scope of surveillance, and improving user comfort. In addition to tracking sleep posture and
behavior, it has further expanded to include the monitoring of respiratory rate and heart rate.

INTEGRATION OF TEXTILE HEALTH MONITORING SYSTEM
Integration strategies
If fiber- or yarn-based sensors and LEDs are employed in the sensor module and display module, they can
form multiple sensing and display pixels through the previously described five textile structures. However, if
other flexible electronic devices are integrated into textiles, two connection steps require attention: the
mechanical connection with the textile material and the electrical connection integrated into the conductive
structure. Both connections must be functionally reliable. The mechanical connection involves securely
attaching electronic components to the textile, considering the stability and durability of the connection
while ensuring the softness and comfort of the textile. Mechanical connections can be achieved through
sewing, adhesive bonding, or other textile processing techniques, similar to traditional ICs and
multifunctional devices on two-dimensional wafers. Currently, limitations on scaling down and challenges
in electronic circuit configuration remain significant obstacles.

Recently, Hwang et al. proposed a technology for integrating electronic devices such as transistors,
inverters, ring oscillators, and thermocouples onto the outer surface of a one-dimensional microfiber
[245]
substrate, as shown in Figure 10A . Using capillary-assisted coating methods and high-resolution
maskless lithography techniques, multiple micro-devices can be rapidly integrated onto a very narrow and
thin fiber surface. Subsequent evaluations of the electronic characteristics of the micro-devices on the fiber
included assessments of switching and data processing capabilities, as well as units for sensing or converting
light and thermal signals. Test results indicate that this mechanical connection technology provides the
device with good stability and flexibility, presenting a viable strategy for manufacturing high-density
electronic microfibers.

Notably, while functional fiber assembly has advanced, current wireless modules and microelectronics still
rely on silicon chips and batteries, which are bulky and rigid, adversely affecting textile functionality and
comfort. Yang et al. addressed this challenge by proposing a human body coupling energy interaction