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.

Designing artificial cells to harness the biological ion concentration gradient


Cell membranes contain numerous nanoscale conductors in the form of ion channels and ion pumps1,2,3,4 that work together to form ion concentration gradients across the membrane to trigger the release of an action potential1,5. It seems natural to ask if artificial cells can be built to use ion transport as effectively as natural cells. Here we report a mathematical calculation of the conversion of ion concentration gradients into action potentials across different nanoscale conductors in a model electrogenic cell (electrocyte) of an electric eel. Using the parameters extracted from the numerical model, we designed an artificial cell based on an optimized selection of conductors. The resulting cell is similar to the electrocyte but has higher power output density and greater energy conversion efficiency. We suggest methods for producing these artificial cells that could potentially be used to power medical implants and other tiny devices.

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

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


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

Figure 1: Anatomy of the electric eel and structure of the natural electrocyte.
Figure 2: Schematic diagram of a system of electrogenic cells used in the simulations, and subsequent action potential formation.
Figure 3: A comparison of action potentials formed in the electrocyte, artificial cell and pseudo squid giant axon.
Figure 4: A comparison of action potentials formed in the electrocyte, artificial cell and pseudo squid giant axon.


  1. Hodgkin, A. & Huxley, A. A quantitative description of membrane current and its application to conduction and excitation in nerve. J. Physiol. 117, 500–544 (1952).

    Article  CAS  Google Scholar 

  2. Altamirano, M. Electrical properties of the innervated membrane of the electroplax of electric eel. J. Cell. Physiol. 46, 249–277 (1955).

    Article  CAS  Google Scholar 

  3. Mermelstein, C., Costa, M. & Neto, V. The cytoskeleton of the electric tissue of Electrophorus electricus, L.*. Ann. Acad. Bras. Cienc. 72, 341–351 (2000).

    Article  CAS  Google Scholar 

  4. Rosenberg, R. L., Tomiko, S. A. & Agnew, W. S. Single-channel properties of the reconstituted voltage-regulated Na channel isolated from the electroplax of Electrophorus electricus. Proc. Natl Acad. Sci. USA 81, 5594–5598 (1984).

    Article  CAS  Google Scholar 

  5. Keynes, R. & Ferreira, H. Membrane potentials in the electroplates of the electric eel. J. Physiol. 119, 315–351 (1953).

    Article  CAS  Google Scholar 

  6. Gotter, A., Kaetzel, M. & Dedman, J. Electrophorus electricus as a model system for the study of membrane excitability. Comp. Biochem. Physiol. 119A, 225–241 (1998).

    Article  CAS  Google Scholar 

  7. Thornhill, W. B. et al. Molecular cloning and expression of a Kv1.1-like potassium channel from the electric organ of Electrophorus electricus. J. Membr. Biol. 196, 1–8 (2003).

    Article  CAS  Google Scholar 

  8. Hille, B. Ion Channels of Excitable Membranes 3rd edn (Sinauer Associates, Sunderland, MA, 2001).

    Google Scholar 

  9. Tanford, C. Equilibrium state of ATP-driven ion pumps in relation to physiological ion concentration gradients. J. Gen. Physiol. 77, 223–229 (1981).

    Article  CAS  Google Scholar 

  10. Ussing, H. H. The frog skin potential. J. Gen. Physiol. 43, 135–147 (1960).

    Article  CAS  Google Scholar 

  11. Novotny, J. & Jakobsson, E. Computational studies of ion-water flux coupling in the airway epithelium. I. Construction of model. Am. J. Physiol. 270, C1751–C1763 (1996).

    Article  CAS  Google Scholar 

  12. Shenkel, S. & Bezanilla, F. Patch recordings from the electrocytes of electrophorus. Na channel gating currents. J. Gen. Physiol. 98, 465–478 (1991).

    Article  CAS  Google Scholar 

  13. Shenkel, S. & Sigworth, F. Patch recordings from the electrocytes of Electrophorus electricus: Na Currents and PNa/PK variability. J. Gen. Physiol. 97, 1013–1041 (1991).

    Article  CAS  Google Scholar 

  14. Dilger, J. P., McLaughlin, S. G., McIntosh, T. J. & Simon, S. A. The dielectric constant of phospholipid bilayers and the permeability of membranes to ions. Science 206, 1196–1198 (1979).

    Article  CAS  Google Scholar 

  15. Cox, R. T., Coates, C. W. & Brown, M. V. Electric tissue—relations between the structure, electrical characteristics, and chemical processes of electric tissue. J. Gen. Physiol. 28, 187–212 (1945).

    Article  CAS  Google Scholar 

  16. Nachmansohn, D., Cox, R. T., Coates, C. W. & Machado, A. L. Action potential and enzyme activity in the electric organ of Electrophorus electricus. ii. Phosphocreatine as energy source of the action potential. J. Neurophysiol. 6, 383–396 (1943).

    Article  CAS  Google Scholar 

  17. Berg, J., Tymoczko, J. & Stryer, L. Biochemistry (W. H. Freeman and Company, New York, 2001).

    Google Scholar 

  18. Conti, F., Hille, B., Neumcke, B., Nonner, W. & Stampfli, R. Measurement of the conductance of the sodium channel from current fluctuations at the node of Ranvier. J. Physiol. 262, 699–727 (1976).

    Article  CAS  Google Scholar 

  19. Humayun, M. et al. Visual perception in a blind subject with a chronic microelectronic retinal prosthesis. Vision Res. 43, 2573–2581 (2002).

    Article  Google Scholar 

  20. Yrach, G. et al. Light-driven production of ATP catalysed by FoF1-ATP synthase in an artificial photosynthetic membrane. Nature 392, 479–482 (1998).

    Article  Google Scholar 

  21. Drew, B. & Leeuwenburgh, C. Method for measuring ATP production in isolated mitochondria: ATP production in brain and liver mitochondria of Fischer-344 rats with age and caloric restriction. Am. J. Physiol.: Regul. Integr. Comp. Physiol. 285, R1259–R1267 (2005).

    Google Scholar 

  22. Maloney, P. C., Kashket, E. R. & Wilson, T. H. A protonmotive force drives ATP synthesis in bacteria. Proc. Natl Acad. Sci. USA 71, 3896–3900 (1974).

    Article  CAS  Google Scholar 

  23. Romer, W. & Steinem, C. Impedance analysis and single-channel recordings on nano-black lipid membranes based on porous alumina. Biophys. J. 86, 955–965 (2004).

    Article  Google Scholar 

  24. Brinker, J., Lu, Y., Sellinger, A. & Fan, H. Evaporation-induced self-assembly: nanostructures made easy. Adv. Mater. 11, 579–585 (1999).

    Article  CAS  Google Scholar 

  25. Hanke, W. & Schlue, W. Planar Lipid Bilayers: Methods and Applications (Academic Press, San Diego, 1993).

    Google Scholar 

  26. Recio-Pinto, E., Duch, D., Levinson, S. & Urban, B. W. Purified and unpurified sodium channels from eel electroplax in planar lipid bilayers. J. Gen. Physiol. 90, 375–395 (1987).

    Article  CAS  Google Scholar 

  27. Jiang, Y.-B. et al. Sub-10 nm thick microporous membranes made by plasma-defined atomic layer deposition of a bridged silsesquioxane precursor. J. Am. Chem. Soc. 129, 15446–15447 (2007).

    Article  CAS  Google Scholar 

  28. Liu, N., Assink, R. A. & Brinker, C. J. Synthesis and characterization of highly ordered mesoporous thin films with –COOH terminated pore surfaces. Chem. Commun. 370–371 (2003).

  29. Merzlyak, P. G., Capistrano, M. F. P., Valeva, A., Kasianowicz, J. J. & Krasilnikov, O. V. Conductance and ion selectivity of a mesoscopic protein nanopore probed with cysteine scanning mutagenesis. Biophys. J. 89, 3059–3070 (2005).

    Article  CAS  Google Scholar 

  30. Matile, S., Som, A. & Sord, N. Recent synthetic ion channels and pores. Tetrahedron 60, 6405–6435 (2004).

    Article  CAS  Google Scholar 

Download references


We thank F. Sigworth, E. Jakobsson, S. Natarajan, J. Novotny, T.P. Ma and S. Yulke for their discussions and comments. The full description of the procedures used in this paper requires the identification of certain software and operating systems and their suppliers. The inclusion of such information should in no way be construed as indicating that such software or operating systems are endorsed by NIST or are recommended by NIST or that it is necessarily the best software or operating system for the purposes described. This work is supported by the National Centre for Design of Biomimetic Nanoconductors, funded by grant no. PHS 2 PN2 EY016570B from the National Institutes of Health through the NIH Roadmap for Medical Research.

Author information

Authors and Affiliations



J.X. and D.A.L. conceived and designed the experiments. J.X. performed the experiments. J.X. and D.A.L. analysed the data and co-wrote the paper.

Corresponding author

Correspondence to David A. Lavan.

Supplementary information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Xu, J., Lavan, D. Designing artificial cells to harness the biological ion concentration gradient. Nature Nanotech 3, 666–670 (2008).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Find nanotechnology articles, nanomaterial data and patents all in one place. Visit Nano by Nature Research