Table 1 Technology Readiness Level (TRL) of fiber-based soft systems

From: Advances and perspectives in fiber-based electronic devices for next-generation soft systems

Device type

TRL range

Demonstration environment

Mass production readiness

Improvement strategy

Mechanical sensor118,122,123,124,125,126,130,131

3–6

Lab-scale prototypes; Wearable, HMI, and soft robotic applications

Partially compatible with textile manufacturing; most remain at research-level scalability

Material encapsulation, hybrid sensing, structural design, Machine learning-based signal correction

Thermal sensor141,142,143,144,145

4–6

Lab-scale devices; Wearable and industrial safety demos

Moderate; scalable with thermal drawing process, but further process control needed

Thermal conductivity enhancement, encapsulation of moisture barrier, hybrid composites

Chemical sensor30,167,168,169,173

3–5

Lab-scale devices; Wearable, implantable, and industrial safety applications

Limited; Stability and reproducibility need improvement

Enzyme stabilization, molecularly imprinted polymer optimization, humidity control

Electro-physiological sensor57,214,215,216,221

3–6

Research-grade device; In vivo neural recoding and wearable EMG/ECG/EEG systems, skin electronics

Moderate; Long-term stability and biocompatibility remain challenging

Biocompatible materials and coating, interfacial impedance reduction, Algorithm for real-time signal analysis

Generator250,253,263,264,268,271,344

4–6

Early-stage prototype; Wearable applications

Moderate; Mass production demonstrated in select studies

Durable structure for preventing leakage, material optimization, development of complex generation mechanism

Battery276,278,283

3–5

Lab-scale prototype; Integrated smart textile system

Limited; Stability and leakage prevention need improvement

Materials optimization, improvement of electrode structure, implementation of thermal runaway mitigation system

Display device298,299,300

4–6

Pre-commercial prototype; Wearable demos and display-integrated system

Good; Ready for industrial adoption

Spectral tunability, enhancement of mechanical durability

Actuator306,314,315,316,317

4–6

Lab-scale prototype; Soft robotic systems and artificial muscles application

Limited; mass production due to challenges in driven source control

Stable Joule heating design, Machine learning-based feedback control, Improvement of work capacity and accuracy

Stimulator341,342,343

4–6

Lab-scale device; In vivo neural interface and stimulation,

Moderate; Manual or small-scale fabrication processes for most cases, with some studies enabling mass production

Enhancement of charge injection capacity (CIC), Standardization, and systematic establishment of stimulation condition