Bioelectrical enhancement in tissue-electrode coupling with metamorphic-stage insertions for insect machine interfaces

Implanting microtechnologies into insects with an aim of domesticating its locomotion poses certain challenges, however, performing surgical implantation during the early stages of metamorphic growth was shown to mitigate some of the related detriments. This study reports the bioelectrical enhancement at the tissue-electrode interface allowed with these metamorphic stage insertions, where the electrodes implanted in the insect during the early pupal stages and right after emergence were compared. An average 1 kHz impedance of 8.9 kΩ was obtained with pupal stage inserted electrodes, ten days after the emergence, as compared to 12.1 kΩ observed when electrodes were implanted in the adult state. Charge storage capacity also increased to 52 mC/cm² from 38 mC/cm² with the early metamorphic insertions. The performed voltage excursion studies also confirmed the enhancement demonstrating an increase from 3.5 mC/cm² to 5.1 mC/cm² in the injectable amount of charge in the water window.