N.G Andrew, H. Rathnayake
University of North Carolina Greensboro,
United States
Keywords: biocapacitor, metal-organic framework, MIL-88B, E.coli
Summary:
The increase in energy demand led to remarkable research activities on energy generation, storage, and conversion, and many different kinds of nanoscale materials have been explored to harness energy. However, recently microorganisms including bacteria and algae have been shown to display significant roles in developing high-performance probes owing to their abilities to reproduce fast, self-repair, self-assembly, and wide range of biosynthetic capabilities. Among a wide variety of microbes, bacteria have been well studied offering their adaptation to broaden research directions for developing a variety of sustainable energy generation, conversion, and storage systems with either improved or new capabilities and performance. Herein, we have developed a high-performance bio-capacitor interfacing live cell of E.coli, with a functional metal-organic framework (MOF), MIL-88B MOF. Understanding interactions at the interface of E. coli and MOF, the charge-capacitive nature of this hybrid material is evaluated for use as an active cathode material for fabricating a bio-capacitor. Por results prove that the MIL-MOF aids in stimulating the bacteria's metabolic electron transfer processes by modulating charge injections at the E.coli/MOF to generate charge capacity through the extracellular electron transfer processes followed by storing charges at the electrode surface. The bio-capacitor constructed from this hybrid material exhibits a charge capacity of 399 Fg-1 at a scan rate of 5 mV/s compared to the charge capacity of 195 Fg-1 for the devices constructed only from bacteria at the same scan rate. Our results suggest the potential of MIL-88B MOF as an external mediator in facilitating electron transfer at the E.coli interface to generate a higher charge capacity twice the magnitude of E.coli charge capacity. This study reveals that by combining the distinctive functionalities of living bacteria with biocompatible abiotic MIL-MOFs, it is possible to create smart interfacial biosystems for charge generation and storage with programmable features.