The emerging personal healthcare has significantly propelled the development of advanced wearable electronics with novel functions of providing diagnostic information and point-of-care therapies for specific diseases. However, it is still challenging to simultaneously achieve high sensitivity for health biomonitoring and multifunction integration for pointof-care therapies in a one single flexible, lightweight yet robust fiber-based device. Here, a knittable and sewable spandex yarn with conductive nacremimetic composite coating has been developed through an alternant dipcoating method employing MXene nanosheets as the "brick" and polydopamine (PDA)/Ni 2+ as the "mortar". The resultant spandex yarn coating with MXene/PDA/Ni 2+ (MPNi@Spandex) can be assembled as a strain sensor with high sensitivity (up to 5.7 × 10 4 for the gauge factor), wide sensing range (∼61.2%), and low detection limit (0.11%) to monitor the biological activities of the human body. Furthermore, MPNi@Spandex displays great potential to give on-demand thermotherapy by virtue of the fast response to near-infrared irradiation, controllable surface temperature, and applicability even under sewing conditions. In addition, MPNi@Spandex knitted textiles demonstrate a strong antibacterial effect due to the sharp edges, anionic, and hydrophilic nature of MXene nanosheets. Remarkably, near-infrared irradiation further improves the bacteriakilling efficiency of an MPNi@Spandex knitted textile to more than 99.9%. This work paves the way for the design of multifunctional wearable electronics with an all-in-one theranostic platform for personal healthcare.

Wearable devices made of degradable fibers are rising stars in smart healthcare by virtue of their light weight, flexibility, and weavability. Silk protein is one promising platform for ideal fiber-type electronic devices due to its inherent biocompatibility and biodegradability. However, it remains a challenge for conductive silk-based fiber electronics to achieve high stretchability and skin-like softness. Here, hygroscopic calcium-modified MXene/silk nanocomposite fibers (Ca@MSNFs) are fabricated by decorating the wet-spun MXene/silk fibers with hygroscopic CaCl2, exhibiting 3.2 g g–1 water capture capacity at 90% relative humidity (RH), high stretchability (279.9%), degradability, repairability, and freeze-resistance (−18 °C). Furthermore, the Ca@MSNFs are assembled as humidity/strain sensors to monitor respiratory signals and body movements, showing great promise for the diagnosis of apnea syndrome and rehabilitation training. Moreover, Ca@MSNFs are degradable and do not cause pollution or environmental damage. Therefore, this work offers a promising strategy for constructing stretchable and degradable electronic devices for advanced healthcare applications.