E-textiles have recently gained significant traction in the development of soft wearables for healthcare applications. To improve user comfort and reduce the number of manufacturing steps, computer numerical control (CNC) knitting can be used to make stretchable conductive knits with tunable macroscopic electrical and mechanical properties by varying the yarn combination and the arrangement of stitch types at the meso-scale. With a single manufacturing step, seamless wearables with a variety of electrical components can be fabricated.

To demonstrate a potential application of this technology, a fully knitted smart knee brace for long-term unsupervised monitoring of lower-limb activities was developed. The flexible strain sensor, interconnects, and resistor were knitted as a potential divider circuit. The strain sensor signal responds to the flexing of the knee joint, and a comparison with motion capture data shows good correlation between the knitted strain sensor signal and the motion capture data. The technology can potentially be applied in the medicine, sports, and occupational health fields.

Further reading:
Gupta, U., Lau, J.L., Chia, P.Z., Tan, Y.Y., Ahmed, A., Tan, N.C., Soh, G.S. and Low, H.Y. (2023). All Knitted and Integrated Soft Wearable of High Stretchability and Sensitivity for Continuous Monitoring of Human Joint Motion. Advanced Healthcare Materials [online]. 12:21. Available from: <https://doi.org/10.1002/adhm.202202987>.

Lau, J.L., Gupta, U., Chia, P.Z., Tan, Y.Y., Soh, G.S. and Low, H.Y. (2023). Design and Performance Evaluation of a Fully Integrated Knitted Knee Brace for Knee Motion Sensing. In: EMBC 2023: 45th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 24-27 July 2023, Sydney.

Chia, P.Z., Gupta, U., Tan, Y.Y., Lau, J.L., Ahmed, A., Soh, G.S. and Low, H.Y. (2021). Effect of Stitch Pattern on the Electrical Properties of Wale-wise Knitted Strain Sensors and Interconnects. In: IEEE Sensors 2021, 31 October – 4 November 2021, Virtual conference.

Gupta, U., Lau, J.L., Ahmed, A., Chia, P.Z., Soh, G.S. and Low, H.Y. (2021). Soft Wearable Knee Brace with Embedded Sensors for Knee Motion Monitoring. In: EMBC 2021: 43rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 1-5 November 2021, Virtual conference.