Functional ingestible capsules hold promise for a variety of diagnostic and therapeutic applications. However, the lack of realistic and practical power supply solutions has severely hampered the development of capturable electronics. Microbial fuel cells (MFCs) have great potential as power sources for such devices, as the intestinal environment maintains a constant internal temperature and neutral pH. These conditions and a continuous supply of nutrient-rich organic matter are the perfect environment for generating long-lasting energy. Although small MFCs to date have shown many promising applications, little is known about their potential for power generation in the human intestinal environment. In this study, we report on the design and manipulation of microbial biobattery capsules for ingestible applications. Dormant endospores of Bacillus subtilis are storable anodic biocatalysts that, when revived by nutrient-rich intestinal fluids, provide energy on demand. A conductive porous poly(3,4-ethylenedioxythiophene) polystyrene sulfonic acid hydrogel anode enables the world’s smallest MFC with excellent electrical performance. Moreover, the oxygen-rich cathode maintains effective cathodic capacity even in an oxygen-deficient intestinal environment. As a proof-of-concept demonstration in stimulated intestinal fluid, the biobattery capsule produced a current density of 470 μA cm and a power density of 98 μW cm, demonstrating its practical efficacy as a novel and single energy source. guaranteed. For ingestion applications in the small intestine.
Date: Dec 09, 2022
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