Piezoelectric nanogenerators with bacterial cellulose-ZnO composites for human self-powered healthcare sensors

This study pioneers a high-performance, eco-friendly piezoelectric nanogenerator by integrating bacterial cellulose (BC) with zinc oxide (ZnO) nanoparticles, offering a novel pathway for next-generation self-powered medical sensors. Unlike conventional rigid generators, the BC/ZnO composite uniquely combines natural flexibility, biodegradability, and high piezoelectric responsiveness, making it ideal for conformal integration with human skin. Systematic optimization of ZnO content revealed that at 20 wt% (BZ4 membrane), the device achieved a peak output voltage of 0.12 V and a maximum piezoelectric constant of 25.6 pC/N under a 5 N load—five times greater than that of pure BC. The sensor exhibited excellent pressure sensitivity (about 0.5 V/N) and retained over 95 % of its performance after 10,000 mechanical cycles. Most notably, the self-powered sensor demonstrated real-time monitoring of human pulse and respiration with no external power, showcasing its practical viability. This work introduces an innovative, sustainable solution for flexible bioelectronic interfaces, paving the way for intelligent health monitoring and autonomous medical diagnostics.