Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Energy extraction from the biologic battery in the inner ear


Endocochlear potential (EP) is a battery-like electrochemical gradient found in and actively maintained by the inner ear1,2. Here we demonstrate that the mammalian EP can be used as a power source for electronic devices. We achieved this by designing an anatomically sized, ultra-low quiescent-power energy harvester chip integrated with a wireless sensor capable of monitoring the EP itself. Although other forms of in vivo energy harvesting have been described in lower organisms3,4,5, and thermoelectric6, piezoelectric7 and biofuel8,9 devices are promising for mammalian applications, there have been few, if any, in vivo demonstrations in the vicinity of the ear, eye and brain. In this work, the chip extracted a minimum of 1.12 nW from the EP of a guinea pig for up to 5 h, enabling a 2.4 GHz radio to transmit measurement of the EP every 40–360 s. With future optimization of electrode design, we envision using the biologic battery in the inner ear to power chemical and molecular sensors, or drug-delivery actuators for diagnosis and therapy of hearing loss and other disorders.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: Anatomy and physiology of the inner ear.
Figure 2: Schematic of the endoelectronics chip and equivalent circuit model of the endocochlear potential and inner ear tissues.
Figure 3: Physical implementation and measurement results of the endoelectronics system.

Similar content being viewed by others


  1. Von Bekesy, G. Resting potentials inside the cochlear partition of the guinea pig. Nature 169, 241–242 (1952).

    Article  CAS  Google Scholar 

  2. Hibino, H., Nin, F., Tsuzuki, C. & Kurachi, Y. How is the highly positive endocochlear potential formed? The specific architecture of the stria vascularis and the roles of the ion-transport apparatus. Pflügers Arch. 459, 521–533 (2010).

    Article  CAS  Google Scholar 

  3. Himes, C., Carlson, E., Ricchiuti, R.J., Otis, B.P. & Parviz, B.A. Ultralow voltage nanoelectronics powered directly, and solely, from a tree. IEEE Trans. NanoTechnol. 9, 2–5 (2010).

    Article  Google Scholar 

  4. Rasmussen, M., Ritzmann, R.E., Lee, I., Pollack, A.J. & Scherson, D. An implantable biofuel cell for a live insect. J. Am. Chem. Soc. 134, 1458–1460 (2012).

    Article  CAS  Google Scholar 

  5. Halámková, L. et al. Implanted biofuel cell operating in a living snail. J. Am. Chem. Soc. 134, 5040–5043 (2012).

    Article  Google Scholar 

  6. Hochbaum, A.I. et al. Enhanced thermoelectric performance of rough silicon nanowires. Nature 451, 163–167 (2008).

    Article  CAS  Google Scholar 

  7. Qin, Y., Wang, X. & Wang, Z.L. Microfibre–nanowire hybrid structure for energy scavenging. Nature 451, 809–813 (2008).

    Article  CAS  Google Scholar 

  8. Chaudhuri, S.K. & Lovley, D.R. Electricity generation by direct oxidation of glucose in mediatorless microbial fuel cells. Nat. Biotechnol. 21, 1229–1232 (2003).

    Article  CAS  Google Scholar 

  9. Rapoport, B.I., Kedzierski, J.T. & Sarpeshkar, R. A glucose fuel cell for implantable brain-machine interfaces. PLoS One 7, e38436 (2012.

    Article  CAS  Google Scholar 

  10. Starner, T. & Paradiso, J.A. Human-generated power for mobile electronics. in Low Power Electronics Design (ed. Piquet, C.) 1–35 (CRC Press, 2004).

  11. Donelan, J.M. et al. Biomechanical energy harvesting: generating electricity during walking with minimal user effort. Science 319, 807–810 (2008).

    Article  CAS  Google Scholar 

  12. Bullen, R.A., Arnot, T.C., Lakeman, J.B. & Walsh, F.C. Biofuel cells and their development. Biosens. Bioelectron. 21, 2015–2045 (2006).

    Article  CAS  Google Scholar 

  13. Dallos, P. Some electrical circuit properties of the organ of Corti. I. Analysis without reactive elements. Hear. Res. 12, 89–119 (1983).

    Article  CAS  Google Scholar 

  14. Takeuchi, S., Ando, M. & Kakigi, A. Mechanism generating endocochlear potential: role played by intermediate cells in stria vascularis. Biophys. J. 79, 2572–2582 (2000).

    Article  CAS  Google Scholar 

  15. Lang, H., Schulte, B.A. & Schmiedt, R.A. Endocochlear potentials and compound action potential recovery: functions in the C57BL/6J mouse. Hear. Res. 172, 118–126 (2002).

    Article  CAS  Google Scholar 

  16. Zidanic, M. & Brownell, W.E. Fine structure of the intracochlear potential field. I. The silent current. Biophys. J. 57, 1253–1268 (1990).

    Article  CAS  Google Scholar 

  17. Fernandez, C. Dimensions of the cochlea (guinea pig). J. Acoust. Soc. Am. 24, 519–523 (1952).

    Article  Google Scholar 

  18. Swanson, R.M. & Meindl, J.D. Ion-implanted complementary MOS transistors in low-voltage circuits. IEEE ISSCC Dig. Tech. Papers 192–193 (1972).

  19. Chen, P.-H. et al. A 95mV-startup step-up converter with VTH-tuned oscillator by fixed-charge programming and capacitor pass-on scheme. IEEE ISSCC Dig. Tech. Papers 216–217 (2011).

  20. Ramadass, Y.K. & Chandrakasan, A.P. A battery-less thermoelectric energy harvesting interface circuit with 35mV startup voltage. IEEE J. Solid-State Circuits 46, 333–341 (2011).

    Article  Google Scholar 

  21. Shimamura, T. et al. Nano-watt power management and vibration sensing on a dust-size batteryless sensor node for ambient intelligence applications. IEEE ISSCC Dig. Tech. Papers 540–541 (2010).

  22. Wieckowski, M., Chen, G.K., Seok, M., Blaauw, D. & Sylvester, D.D. A hybrid DC-DC converter for sub-microwatt sub-1V implantable applications. IEEE Symposium on VLSI Circuits 166–167 (2009).

  23. Zhang, F. et al. A batteryless 19uW MICS/ISM-band energy harvesting body area sensor node SoC. IEEE ISSCC Dig. Tech. Papers 298–299 (2012).

  24. Roy, K., Mukhopadhyay, S. & Mahmoodi-Meimand, H. Leakage current mechanisms and reduction techniques in deep-submicrometer CMOS circuits. Proc. IEEE 91, 305–327 (2003).

    Article  CAS  Google Scholar 

  25. Chen, G. et al. A cubic-millimeter energy-autonomous wireless intraocular pressure monitor. IEEE ISSCC Dig. Tech. Papers, 310–311 (2011).

  26. Chow, E.Y., Chlebowski, A.L. & Irazoqui, P.P. Mixed-signal integrated circuits for self-contained sub-cubic millimeter biomedical implants. IEEE Trans. BioCAS 4, 340–349 (2010).

    Google Scholar 

  27. Mason, M.J. Middle ear structures in fossorial mammals: comparison with non-fossorial species. J. Zool. (Lond.) 255, 467–486 (2001).

    Article  Google Scholar 

  28. Mills, D.M., Norton, S.J. & Rubel, E.W. Vulnerability and adaptation of distortion product otoacoustic emissions to endocochlear potential variation. J. Acoust. Soc. Am. 94, 2108–2122 (1993).

    Article  CAS  Google Scholar 

  29. Von Bekesy, G. DC resting potentials inside the cochlear partition. J. Acoust. Soc. Am. 24, 72–76 (1952).

    Article  Google Scholar 

  30. Fayad, J.N., Semaan, M.T., Meier, J.C. & House, J.W. Hearing results using the Smart piston prosthesis. Otol. Neurotol. 30, 1122–1127 (2009).

    Article  Google Scholar 

  31. Mowry, S.E., Woodson, E. & Gantz, B.J. New frontiers in cochlear implantation: acoustic plus electric hearing, hearing preservation, and more. Otolaryngol. Clin. North Am. 45, 187–203 (2012).

    Article  Google Scholar 

Download references


We acknowledge support from the C2S2 Focus Center and the Interconnect Focus Center, two of six research centers funded under the Focus Center Research Program (FCRP), a Semiconductor Research Corporation entity (A.P.C., P.P.M., S.B.), and from US National Institutes of Health grants K08 DC010419 (K.M.S.) and T32 DC00038 (A.C.L.) and the Bertarelli Foundation (K.M.S.). We thank J.J. Guinan Jr. for experimental assistance and advice, and B. Zhu for preliminary studies.

Author information

Authors and Affiliations



A.P.C. and K.M.S. conceived the project. P.P.M., A.C.L., S.B., A.P.C. and K.M.S. designed experiments. P.P.M., A.C.L. and S.B. performed the experiments. P.P.M. and S.B. designed and implemented the electronic chip. A.C.L. performed the EP measurements. P.P.M., A.C.L., S.B., A.P.C. and K.M.S. wrote and edited the manuscript.

Corresponding authors

Correspondence to Anantha P Chandrakasan or Konstantina M Stankovic.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Text and Figures

Supplementary Figures 1–3 (PDF 125 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Mercier, P., Lysaght, A., Bandyopadhyay, S. et al. Energy extraction from the biologic battery in the inner ear. Nat Biotechnol 30, 1240–1243 (2012).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing