Smart fabrics that can harvest ambient energy and provide diverse sensing functionality via triboelectric effects have evoked great interest for next-generation healthcare electronics. Herein, a novel borophene/ecoflex nanocomposite is developed as a promising triboelectric material with tailorability, durability, mechanical stability, and flexibility. The addition of borophene nanosheets enables the borophene/ecoflex nanocomposite to exhibit tunable surface triboelectricity investigated by Kelvin probe force microscopy. The borophene/ecoflex nanocomposite is further fabricated into a fabric-based triboelectric nanogenerator (B-TENG) for mechanical energy harvesting, medical assistive system, and wound healing applications. The durability of B-TENG provides consistent output performance even after severe deformation treatments, such as folding, stretching, twisting, and washing procedures. Moreover, the B-TENG is integrated into a smart keyboard configuration combined with a robotic system to perform an upper-limb medical assistive interface. Furthermore, the B-TENG is also applied as an active gait phase sensing system for instantaneous lower-limb gait phase visualization. Most importantly, the B-TENG can be regarded as a self-powered in vitro electrical stimulation device to conduct continuous wound monitoring and therapy. The as-designed B-TENG not only demonstrates great potential for multifunctional self-powered healthcare sensors, but also for the promising advancements toward wearable medical assistive and therapeutic systems.