Acetobacter Biofilm: Electronic Characterization and Reactive Transduction of Pressure.

Alessandro Chiolerio,Andrew Adamatzky

doi:10.1021/acsbiomaterials.0c01804

Abstract

The bacterial skin studied here is a several centimeter-wide colony of Acetobacter aceti living on a cellulose-based hydrogel. We demonstrate that the colony exhibits trains of spikes of extracellular electrical potential, with amplitudes of the spikes varying from 1 to 17 mV. The bacterial pad responds to mechanical stimulation with distinctive changes in its electrical activity. While studying the passive electrical properties of the bacterial pad, we found that the pad provides an open-circuit voltage drop (between 7 and 25 mV) and a small short-circuit current (1.5–4 nA). We also observed by pulsed tomography and spatially resolved impedance spectroscopy that the conduction occurs along preferential paths, with the peculiar side-effect of having a higher resistance between closer electrodes. We speculate that the Acetobacter biofilms could be utilized in the development of living skin for soft robots: such skin will act as an electrochemical battery and a reactive tactile sensor. It could even be used for wearable devices.

Highlights

Flexible artificial skins[1−3] represent a fast-growing research field, involving several disciplines under the umbrella of novel electronics and materials science and, in the last few years, their biology and sustainability
Living organisms could perfectly match unconventional living architectures[21] and soft and self-growing robots.[22−25] For example, tactile, color sensors were fabricated using slime mold Physarum polycephalum, which are unicellular macroscopic fungi that process their nutrients through a complex network that preserve their adaptability and regeneration capabilities.[26−28] Fungal electrical activity was studied and demonstrated to be in line with typical sensing and computational requirements.[29−31] Fungi have been proposed as human skin surrogates for wound healing purposes.[32−37] More recently, we have demonstrated a reactive fungal wearable made out of Pleurotus ostreatus mycelium.[38]
We have analyzed the electronic and spiking properties of a living Acetobacter aceti biofilm, using advanced technologies which are currently employed in the characterization of condensed matter samples and devices

Summary

INTRODUCTION

Flexible artificial skins[1−3] represent a fast-growing research field, involving several disciplines under the umbrella of novel electronics and materials science and, in the last few years, their biology and sustainability. Living organisms could perfectly match unconventional living architectures[21] and soft and self-growing robots.[22−25] For example, tactile, color sensors were fabricated using slime mold Physarum polycephalum, which are unicellular macroscopic fungi that process their nutrients through a complex network that preserve their adaptability and regeneration capabilities.[26−28] Fungal electrical activity was studied and demonstrated to be in line with typical sensing and computational requirements.[29−31] Fungi have been proposed as human skin surrogates for wound healing purposes.[32−37] More recently, we have demonstrated a reactive fungal wearable made out of Pleurotus ostreatus mycelium.[38].

METHODS

RESULTS AND DISCUSSION

CONCLUSIONS

■ REFERENCES