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Abstract Functioning ingestible capsules offer tremendous promise for a plethora of diagnostic and therapeutic applications. However, the absence of realistic and practical power solutions has greatly hindered the development of ingestible electronics. Microbial fuel cells (MFCs) hold great potential as power sources for such devices as the small intestinal environment maintains a steady internal temperature and a neutral pH. Those conditions and the constant supply of nutrient‐rich organics are a perfect environment to generate long‐lasting power. Although previous small‐scale MFCs have demonstrated many promising applications, little is known about the potential for generating power in the human gut environment. Here, this work reports the design and operation of a microbial biobattery capsule for ingestible applications. DormantBacillus subtilisendospores are a storable anodic biocatalyst that will provide on‐demand power when revived by nutrient‐rich intestinal fluids. A conductive, porous, poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate hydrogel anode enables superior electrical performance in what is the world's smallest MFC. Moreover, an oxygen‐rich cathode maintains its effective cathodic capability even in the oxygen‐deficit intestinal environment. As a proof‐of‐concept demonstration in stimulated intestinal fluid, the biobattery capsule produces a current density of 470 µA cm−2and a power density of 98 µW cm−2, ensuring its practical efficacy as a novel and sole power source for ingestible applications in the small intestine.
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Toward Sustainable, High‐Performance, and Scalable On‐Chip Biopower: Microbial Biobatteries with 3D‐Printed Stainless Steel Anodes and Spore‐Based Biocatalysts
The rapid proliferation of the Internet of Things (IoT) necessitates compact, sustainable, and autonomous energy sources for distributed electronic devices. Microbial fuel cells (MFCs) offer an eco‐friendly alternative by converting organic matter into electrical energy using living micro‐organisms. However, their integration into microsystems faces significant challenges, including incompatibility with microfabrication, fragile anode materials, low electrical conductivity, and compromised microbial viability. Here, this study introduces a microscale biobattery platform integrating laser powder bed fusion‐fabricated 316L stainless steel anodes with resilient, spore‐formingBacillus subtilisbiocatalysts. The 3D‐printed gyroid scaffolds provide high surface‐to‐volume ratios, submillimeter porosity, and tunable roughness, enhancing microbial colonization and electron transfer. The stainless steel ensures mechanical robustness, chemical stability, and superior conductivity.Bacillus subtilisspores withstand harsh conditions, enabling prolonged storage and rapid, on‐demand activation. The biobattery produces 130 μW of power, exceeding conventional microscale MFCs, with exceptional reuse stability. A stack of six biobatteries achieves nearly 1 mW, successfully powering a 3.2‐inch thin‐film transistor liquid crystal display via capacitor‐assisted energy buffering, demonstrating practical applicability. This scalable, biologically resilient, and fabrication‐compatible solution advances autonomous electronic systems for IoT applications.
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- Award ID(s):
- 2410431
- PAR ID:
- 10640179
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Energy and Sustainability Research
- ISSN:
- 2699-9412
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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