Self-powered implantable medical electronic devices that harvest biomechanical energy from cardiac motion, respiratory movement and blood flow are part of a paradigm shift that is on the horizon. Here, we demonstrate a fully implanted symbiotic pacemaker based on an implantable triboelectric nanogenerator, which achieves energy harvesting and storage as well as cardiac pacing on a large-animal scale. The symbiotic pacemaker successfully corrects sinus arrhythmia and prevents deterioration. The open circuit voltage of an implantable triboelectric nanogenerator reaches up to 65.2 V. The energy harvested from each cardiac motion cycle is 0.495 μJ, which is higher than the required endocardial pacing threshold energy (0.377 μJ). Implantable triboelectric nanogenerators for implantable medical devices offer advantages of excellent output performance, high power density, and good durability, and are expected to find application in fields of treatment and diagnosis as in vivo symbiotic bioelectronics.

Mechanical energy in vivo could be harvested by BD-TENG in a designed time frame.

High-resolution dynamic force mapping of cardiomyocytes is revealed by nanopillars with piezo-phototronic effect.

Triboelectric nanogenerators (TENGs) are highly promising as implantable, degradable energy sources and self‐powered sensors. However, the degradable triboelectric materials are often limited in terms of contact electrification and mechanical properties. Here, a bio‐macromolecule‐assisted toughening strategy for PVA aerogel‐based triboelectric materials is proposed. By introducing β‐lactoglobulin fibrils (BF) into the PVA aerogel network, the material's mechanical properties while preserving its swelling resistance is significantly enhanced. Compared to pure PVA porous film, the BF‐PVA porous film exhibits an eightfold increase in fracture strength (from 1.92 to 15.48 J) and a fourfold increase in flexibility (from 10.956 to 39.36 MPa). Additionally, the electrical output of BF‐PVA in triboelectric performance tests increased nearly fivefold (from 45 to 203 V). Leveraging these enhanced properties, a biodegradable TENG (bi‐TENG) for implantable muscle activity sensing is developed, achieving real‐time monitoring of neuromuscular processes. This innovation holds significant potential for advancing implantable medical devices and promoting new applications in bio‐integrated electronics.