ABSTRACT The pervasive model for a solvated, ion-filled nanopore is often a resistor in parallel with a capacitor. For conical nanopore geometries, here we propose the inclusion of a

Warburg-like element, which is necessary to explain otherwise anomalous observations such as negative capacitance and low-pass filtering of translocation events (we term this phenomenon as

Warburg filtering). The negative capacitance observed here has long equilibration times and memory (that is, mem-capacitance) at negative voltages. We used the transient occlusion of the

pore using λ-DNA and 10 kbp DNA to test whether events are being attenuated by purely ionic phenomena when there is sufficient amplifier bandwidth. We argue here that both phenomena can be

instead on the complex and nonlinear storage of ions that enter dis-equilibrium during molecular transit. Access through your institution Buy or subscribe This is a preview of subscription

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* Learn about institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS ON THE ORIGINS OF CONDUCTIVE PULSE SENSING INSIDE A NANOPORE

Article Open access 13 May 2022 ASSEMBLY OF TRANSMEMBRANE PORES FROM MIRROR-IMAGE PEPTIDES Article Open access 14 September 2022 SOLID-STATE NANOPORE SYSTEMS: FROM MATERIALS TO APPLICATIONS

Article Open access 11 June 2021 DATA AVAILABILITY Raw data including _I_–_V_ curves, translocation data and COMSOL reports are provided in Supplementary Data 1–7. CODE AVAILABILITY The

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nanopores under high ionic strength and concentration gradients. _Nanoscale_ 9, 930–939 (2017). Article  CAS  PubMed  Google Scholar  Download references ACKNOWLEDGEMENTS This work was

supported by the NIH (grant no. R35GM151115). We would like to thank the University of California at Riverside for the software suites provided for this study. AUTHOR INFORMATION Author

notes * These authors contributed equally: Nasim Farajpour, Y. M. Nuwan D. Y. Bandara. AUTHORS AND AFFILIATIONS * Department of Bioengineering, University of California, Riverside,

Riverside, CA, USA Nasim Farajpour, Y. M. Nuwan D. Y. Bandara, Lauren Lastra & Kevin J. Freedman Authors * Nasim Farajpour View author publications You can also search for this author

inPubMed Google Scholar * Y. M. Nuwan D. Y. Bandara View author publications You can also search for this author inPubMed Google Scholar * Lauren Lastra View author publications You can also

search for this author inPubMed Google Scholar * Kevin J. Freedman View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS N.F. conducted the DNA

translocation experiments under the 10 mM KCl conditions and analysed the corresponding data. Y.M.N.D.Y.B. conducted and analysed the negative mem-capacitance effects in the _I_–_V_ curve

data. L.L. conducted the DNA translocation experiments under asymmetric salt conditions (1 M/4 M KCl). K.J.F. conceived and planned the experiments as well as performed the COMSOL

simulations. CORRESPONDING AUTHOR Correspondence to Kevin J. Freedman. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing interests. PEER REVIEW PEER REVIEW INFORMATION

_Nature Nanotechnology_ thanks Ralph H. Scheicher and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. ADDITIONAL INFORMATION PUBLISHER’S NOTE

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. SUPPLEMENTARY INFORMATION SUPPLEMENTARY INFORMATION Supplementary Figs.

1–23, Table 1 and discussions. SUPPLEMENTARY DATA 1 COMSOL report 1. SUPPLEMENTARY DATA 2 COMSOL report 2. SUPPLEMENTARY CODE 1 Exponential fitting code. SUPPLEMENTARY DATA 3 _I_–_V_

recording in 10 mM KCl SUPPLEMENTARY DATA 4 _I_–_V_ recording in 30 mM KCl. SUPPLEMENTARY DATA 5 _I_–_V_ recording in 100 mM KCl. SUPPLEMENTARY DATA 6 _I_–_V_ recording with DNA on both

sides of the pore. SUPPLEMENTARY DATA 7 λ-DNA conductive events. RIGHTS AND PERMISSIONS Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this

article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of

such publishing agreement and applicable law. Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Farajpour, N., Bandara, Y.M.N.D.Y., Lastra, L. _et al._ Negative memory

capacitance and ionic filtering effects in asymmetric nanopores. _Nat. Nanotechnol._ 20, 421–431 (2025). https://doi.org/10.1038/s41565-024-01829-5 Download citation * Received: 30 August

2022 * Accepted: 18 October 2024 * Published: 02 January 2025 * Issue Date: March 2025 * DOI: https://doi.org/10.1038/s41565-024-01829-5 SHARE THIS ARTICLE Anyone you share the following

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