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Power generation from ambient humidity using protein nanowires


Harvesting energy from the environment offers the promise of clean power for self-sustained systems1,2. Known technologies—such as solar cells, thermoelectric devices and mechanical generators—have specific environmental requirements that restrict where they can be deployed and limit their potential for continuous energy production3,4,5. The ubiquity of atmospheric moisture offers an alternative. However, existing moisture-based energy-harvesting technologies can produce only intermittent, brief (shorter than 50 seconds) bursts of power in the ambient environment, owing to the lack of a sustained conversion mechanism6,7,8,9,10,11,12. Here we show that thin-film devices made from nanometre-scale protein wires harvested from the microbe Geobacter sulfurreducens can generate continuous electric power in the ambient environment. The devices produce a sustained voltage of around 0.5 volts across a 7-micrometre-thick film, with a current density of around 17 microamperes per square centimetre. We find the driving force behind this energy generation to be a self-maintained moisture gradient that forms within the film when the film is exposed to the humidity that is naturally present in air. Connecting several devices linearly scales up the voltage and current to power electronics. Our results demonstrate the feasibility of a continuous energy-harvesting strategy that is less restricted by location or environmental conditions than other sustainable approaches.

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Fig. 1: Nanowire devices and electric output.
Fig. 2: Moisture gradient in nanowire film and electric output.
Fig. 3: Mechanisms for electric output.
Fig. 4: Powering from nanowire devices.

Data availability

The data that support the findings of this study are available within the paper and Supplementary Information. Additional supporting data generated during the present study are available from the corresponding author upon reasonable request.


  1. 1.

    Tentzeris, M. M., Georgiadis, A. & Roselli, L. Energy harvesting and scavenging. Proc. IEEE 102, 1644–1648 (2014).

    Article  Google Scholar 

  2. 2.

    Abowd, G. D. & Mynatt, E. D. Charting past, present, and future research in ubiquitous computing. ACM Trans. Comput. Hum. Interact. 7, 29–58 (2000).

    Article  Google Scholar 

  3. 3.

    Parida, B., Iniyan, S. & Goic, R. A review of solar photovoltaic technologies. Renew. Sustain. Energy Rev. 15, 1625–1636 (2011).

    CAS  Article  Google Scholar 

  4. 4.

    Wang, Z. L. Triboelectric nanogenerators as new energy technology for self-powered systems and active mechanical and chemical sensors. ACS Nano 7, 9533–9557 (2013).

    CAS  Article  Google Scholar 

  5. 5.

    Champier, D. Thermoelectric generators: a review of applications. Energy Convers. Manage. 140, 167–181 (2017).

    Article  Google Scholar 

  6. 6.

    Zhao, F., Cheng, H., Zhang, Z., Jiang, L. & Qu, L. Direct power generation from a graphene oxide film under moisture. Adv. Mater. 27, 4351–4357 (2015).

    CAS  Article  Google Scholar 

  7. 7.

    Xue, J. et al. Vapor-activated power generation on conductive polymer. Adv. Funct. Mater. 26, 8784–8792 (2016).

    CAS  Article  Google Scholar 

  8. 8.

    Zhao, F., Liang, Y., Cheng, H., Jiang, L. & Qu, L. Highly efficient moisture-enabled electricity generation from graphene oxide frameworks. Energy Environ. Sci. 9, 912–916 (2016).

    CAS  Article  Google Scholar 

  9. 9.

    Ding, T. et al. All-printed porous carbon film for electricity generation from evaporation-driven water flow. Adv. Funct. Mater. 27, 1700551 (2017).

    Article  Google Scholar 

  10. 10.

    Shen, D. et al. Self-powered wearable electronics based on moisture enabled electricity generation. Adv. Mater. 30, 1705925 (2018).

    Article  Google Scholar 

  11. 11.

    Liu, K. et al. Induced potential in porous carbon films through water vapor adsorption. Angew. Chem. Int. Edn 55, 8003–8007 (2016).

    CAS  Article  Google Scholar 

  12. 12.

    Cheng, H. et al. Spontaneous power source in ambient air of a well-directionally reduced graphene oxide bulk. Energy Environ. Sci. 11, 2839–2845 (2018).

    CAS  Article  Google Scholar 

  13. 13.

    Xue, G. et al. Water-evaporation-induced electricity with nanostructured carbon materials. Nat. Nanotechnol. 12, 317–321 (2017).

    CAS  ADS  Article  Google Scholar 

  14. 14.

    Zhang, Z. et al. Emerging hydrovoltaic technology. Nat. Nanotechnol. 13, 1109–1119 (2018).

    CAS  ADS  Article  Google Scholar 

  15. 15.

    Lovley, D. R. Electrically conductive pili: biological function and potential applications in electronics. Curr. Opin. Electrochem 4, 190–198 (2017).

    CAS  Article  Google Scholar 

  16. 16.

    Lovley, D. R. e-Biologics: fabrication of sustainable electronics with “green” biological materials. MBio 8, e00695 (2017).

    CAS  Article  Google Scholar 

  17. 17.

    Lovley, D. R. & Walker, D. J. F. Geobacter protein nanowires. Front. Microbiol. 10, 2078 (2019).

    Article  Google Scholar 

  18. 18.

    Malvankar, N. S. et al. Tunable metallic-like conductivity in microbial nanowire networks. Nat. Nanotechnol. 6, 573–579 (2011).

    ADS  Article  Google Scholar 

  19. 19.

    Adhikari, R. Y., Malvankar, N. S., Tuominen, M. T. & Lovley, D. R. Conductivity of individual Geobacter pili. RSC Adv. 6, 8354–8357 (2016).

    CAS  Article  Google Scholar 

  20. 20.

    Filman, D. J. et al. Cryo-EM reveals the structural basis of long-range electron transport in a cytochrome-based bacterial nanowire. Commun. Biol. 2, 219 (2019).

    Google Scholar 

  21. 21.

    Wang, F. et al. Structure of microbial nanowires reveals stacked hemes that transport electrons over micrometers. Cell 177, 361–369 (2019).

    CAS  Article  Google Scholar 

  22. 22.

    Feliciano, G. T., Steidl, R. J. & Reguera, G. Structural and functional insights into the conductive pili of Geobacter sulfureducens revealed in molecular dynamics simulations. Phys. Chem. Chem. Phys. 17, 22217 (2015).

    CAS  Article  Google Scholar 

  23. 23.

    Xiao, K. et al. Low energy atomic models suggesting a pilus structure that could account for electrical conductivity of Geobacter sulfurredecens pili. Sci. Rep. 6, 23385 (2016).

    CAS  ADS  Article  Google Scholar 

  24. 24.

    Ho, C. K. & Webb, S. W. Gas Transport in Porous Media (Springer, 2006).

  25. 25.

    Soares, L. C., Bertazzo, S., Burgo, T. A. L., Baldim, V. & Galembeck, F. A new mechanism for the electrostatic charge build-up and dissipation in dielectrics. J. Braz. Chem. Soc. 19, 277–286 (2008).

    CAS  Google Scholar 

  26. 26.

    Gouveia, R. F. & Galembeck, F. Electrostatic charging of hydrophilic particles due to water adsorption. J. Am. Chem. Soc. 131, 11381–11386 (2009).

    CAS  Article  Google Scholar 

  27. 27.

    Ducati, T. R. D., Simoes, L. H. & Galembeck, F. Charge partitioning at gas-solid interfaces: humidity causes electricity buildup on metals. Langmuir 26, 13763–13766 (2010).

    CAS  Article  Google Scholar 

  28. 28.

    Perkins, R. S. Rate laws for elementary chemical reactions. J. Chem. Educ. 51, 254 (1974).

    CAS  Article  Google Scholar 

  29. 29.

    Wright, S. H. Generation of resting membrane potential. Adv. Physiol. Educ. 28, 139–142 (2004).

    Article  Google Scholar 

  30. 30.

    Yin, B., Liu, X., Gao, H., Fu, T. & Yao, J. Bioinspired and bristled microparticles for ultrasensitive pressure and strain sensors. Nat. Commun. 9, 5161 (2018).

    ADS  Article  Google Scholar 

  31. 31.

    Vargas, M. et al. Aromatic amino acids required for pili conductivity and long-range extracellular electron transport in Geobacter sulfurreducens. MBio 4, e00105-13 (2013); erratum 4, e00210-13 (2013).

    Article  Google Scholar 

  32. 32.

    Xiang, J. et al. Ge/Si nanowire heterostructures as high-performance field-effect transistors. Nature 441, 489–493 (2006).

    CAS  ADS  Article  Google Scholar 

  33. 33.

    Yao, J. et al. Nanowire nanocomputer as a finite-state machine. Proc. Natl Acad. Sci. USA 111, 2431–2435 (2014).

    CAS  ADS  Article  Google Scholar 

  34. 34.

    Esteve-Núñez, A., Rothermich, M. M., Sharma, M. & Lovley, D. R. Growth of Geobacter sulfurreducens under nutrient-limiting conditions in continuous culture. Environ. Microbiol. 7, 641–648 (2005).

    Article  Google Scholar 

  35. 35.

    Coppi, M. V., Leang, C., Sandler, S. J. & Lovley, D. R. Development of a genetic system for Geobacter sulfurreducens. Appl. Environ. Microbiol. 67, 3180–3187 (2001).

    CAS  Article  Google Scholar 

  36. 36.

    Tan, Y. et al. Expressing the Geobacter metallireducens PilA in Geobacter sulfurreducens yields pili with exceptional conductivity. MBio 8, e02203-16 (2017).

    CAS  Article  Google Scholar 

  37. 37.

    Tan, Y. et al. Synthetic biological protein nanowires with high conductivity. Small 12, 4481–4485 (2016).

    CAS  ADS  Article  Google Scholar 

  38. 38.

    Feng, J. et al. Giant moisture responsiveness of VS2 ultrathin nanosheets for novel touchless positioning interface. Adv. Mater. 24, 1969–1974 (2012).

    CAS  Article  Google Scholar 

  39. 39.

    Brooks, B. R. et al. CHARMM: the biomolecular simulation program. J. Comput. Chem. 30, 1545–1614 (2009).

    CAS  Article  Google Scholar 

  40. 40.

    Huang, J. et al. CHARMM36m: an improved force field for folded and intrinsically disordered proteins. Nat. Methods 14, 71–73 (2017).

    CAS  Article  Google Scholar 

  41. 41.

    Smart, O. S., Neduvelil, J. G., Wang, X., Wallace, B. A. & Sansom, M. S. P. HOLE: a program for the analysis of the pore dimensions of ion channel structural models. J. Mol. Graph. Model. 14, 354–360 (1996).

    CAS  Article  Google Scholar 

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J.Y. and D.R.L. acknowledge support from a seed fund through the Office of Technology Commercialization and Ventures at the University of Massachusetts, Amherst. J.C. and Xiaorong L. acknowledge support from the National Institutes of Health (grant GM114300 to J.C.). Part of the device fabrication work was conducted in the Center for Hierarchical Manufacturing (CHM), a National Science Foundation (NSF) Nanoscale Science and Engineering Center (NSEC) located at the University of Massachusetts Amherst.

Author information




J.Y. and Xiaomeng L. conceived the project and designed experiments. D.R.L. oversaw material design and production. Xiaomeng L. carried out experimental studies. H.G. helped with device fabrication and characterization. J.E.W. performed material synthesis and imaging. Xiaorong L. and J.C. designed the computational study and analysis. Xiaorong L. performed simulations and analysis. B.Y. performed resistance simulations. T.F. helped with electrode fabrication. J.Y. and D.R.L. wrote the paper. All authors discussed the results and implications and commented on the manuscript at all stages.

Corresponding author

Correspondence to Jun Yao.

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The authors declare no competing interests.

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Peer review information Nature thanks Liangti Qu and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Information

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Liu, X., Gao, H., Ward, J.E. et al. Power generation from ambient humidity using protein nanowires. Nature 578, 550–554 (2020).

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