Fig. 1. Design features and materials of a self-powered intracardiac pacemaker (SICP).

a Schematic illustration of the device in the right ventricle (RV) for converting biomechanical energy from cardiac motion to electricity and regulating arrhythmia, which is composed of an energy harvesting unit (EHU), a power management unit & pacemaker module (PMU&PM), hooks and radiopaque markers. b Internal perspective structure of the device. c Charge transfer (i) before contact, (ii) in contact, and (iii) after contact between two different dielectrics- polyformaldehyde (POM) and polytetrafluoroethylene (PTFE). d Three-dimensional explosive view of SICP. e Photograph of SICP with a weight of 1.75 g and volume of 1.52 cc (diameter = 6.8 mm; length = 42 mm) (Scale bar = 2 cm). f Scanning electron microscope (SEM) images of the surface of POM pellet and PTFE film after treatment by inductively coupled plasma (ICP) technology (Scale bar = 5 μm). The abbreviations are the same in other figures unless otherwise stated.