Triggering triboelectric nanogenerator antibacterial Activities: Effect of charge polarity and host material correlation

Triboelectric nanogenerators (TENGs) offer promising motion-driven energy harvesting for human-machine interactions, particularly in wearable healthcare and biomedical devices. However, direct skin contact demands addressing aggressive bacterial growth risks. The "triangle" interaction between bacteria, electrical stimulation, and host materials has been investigated comprehensively in the present study to facilitate appropriate selfantibacterial designs for TENGs. In so doing, it was revealed that the growth of negatively charged bacterial models (Escherichia coli and Staphylococcus aureus) was inhibited by induced positively charged substrates (Al or graphene oxide (GO)), regardless of the host material's composition due to the direct electrostatic interactions. Electron capture from the bacterial respiratory chain by the substrates leads to the interruption of the bacterial energy supply. In response to negative charges, however, an appreciable host-dependent antibacterial behaviour was observed, with Al showing a negligible bactericidal effect, while GO exhibited robust antibacterial properties. This effect was assigned to reactive oxygen species (ROS) generation, triggered by shuttling the negative charges to the oxygen functional groups in GO, suppressing bacterial growth efficaciously. The observed correlation between the electrostatic charge polarity and the material composition of the substrates (hosting the bacteria) highlights the superiority of ROS induction in the antibacterial properties of TENG. These findings pave the way for developing innovative approaches to control bacterial growth effectively and enhance the applicability of TENGs as advanced wearable devices with inherent antibacterial capabilities.