pith. sign in

arxiv: 1907.05643 · v1 · pith:25D2HDZAnew · submitted 2019-07-12 · ⚛️ physics.bio-ph · physics.app-ph

A Teflon-based system for applying multidirectional voltages to lipid bilayers as a novel platform for membrane proteins

Maki Komiya , Kensaku Kanomata , Ryo Yokota , Yusuke Tsuneta , Madoka Sato , Daichi Yamaura , Daisuke Tadaki , Teng Ma
show 8 more authors
Hideaki Yamamoto Yuzuru Tozawa Albert Marti Jordi Madrenas Shigeru Kubota Fumihiko Hirose Michio Niwano Ayumi Hirano-Iwata
This is my paper

Pith reviewed 2026-05-24 22:15 UTC · model grok-4.3

classification ⚛️ physics.bio-ph physics.app-ph
keywords lipid bilayersion channelslateral voltageTeflon filmmembrane proteinsartificial membraneselectrophysiologymultidirectional voltages
0
0 comments X

The pith

A Teflon microaperture system with surrounding electrodes applies lateral voltages to lipid bilayers and alters ion channel activity without changing baseline membrane properties.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper constructs an artificial bilayer lipid membrane platform on a Teflon film that supports both conventional transmembrane voltages and an independent lateral voltage applied through evaporated titanium electrodes around a microaperture. The authors demonstrate that stable bilayers form reproducibly despite the electrodes and that lateral voltage leaves baseline current, resistance, and capacitance unchanged. In contrast, the same lateral voltage measurably changes the gating behavior of embedded biological ion channels. This setup therefore supplies an additional experimental parameter for dissecting membrane protein function beyond the single transmembrane-potential variable used in conventional recordings.

Core claim

The authors report construction of a BLM system on a Teflon film containing a microaperture surrounded by Ti electrodes. Bilayers form reproducibly in the aperture. Application of lateral voltage produces no significant alteration in baseline current, transmembrane resistance, or transmembrane capacitance. The same lateral voltage, however, clearly modulates the activities of biological ion channels, indicating that lateral voltage constitutes a useful additional parameter for analyzing channel function. The resulting multidirectional-voltage platform is presented as a tool for functional studies of membrane proteins.

What carries the argument

Teflon film microaperture with evaporated Ti electrodes positioned around its perimeter, enabling independent application of lateral membrane voltage alongside the transmembrane voltage.

If this is right

  • Lateral voltage becomes an independent experimental variable that can modulate ion channel gating.
  • Stable artificial bilayers can be formed reproducibly even with electrodes present at the aperture edge.
  • Baseline electrical properties of the bilayer remain intact under applied lateral voltage.
  • The platform extends functional analysis of membrane proteins to conditions with multidirectional electric fields.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The approach could be used to test whether membrane proteins respond differently to in-plane versus perpendicular fields, a distinction that may matter inside cells where local fields are rarely purely transmembrane.
  • Quantitative mapping of channel open probability versus lateral field strength could reveal direction-dependent gating mechanisms not accessible with conventional setups.
  • The system might be combined with fluorescence or patch-clamp recordings to correlate lateral-field effects with structural changes in the same bilayer.
  • A direct test would be to apply the lateral field to channels whose pore axis is known to lie parallel or perpendicular to the membrane plane.

Load-bearing premise

Observed changes in ion channel activity are produced by the intended lateral electric field rather than by electrode artifacts such as local heating, chemical reactions, or nonuniform fields.

What would settle it

A control run in which the same lateral voltage is applied through insulating barriers or with temperature and pH sensors placed at the aperture while channel activity remains unchanged would falsify the claim that the field itself drives the observed effects.

Figures

Figures reproduced from arXiv: 1907.05643 by Albert Marti, Ayumi Hirano-Iwata, Daichi Yamaura, Daisuke Tadaki, Fumihiko Hirose, Hideaki Yamamoto, Jordi Madrenas, Kensaku Kanomata, Madoka Sato, Maki Komiya, Michio Niwano, Ryo Yokota, Shigeru Kubota, Teng Ma, Yusuke Tsuneta, Yuzuru Tozawa.

Figure 1
Figure 1. Figure 1: A schematic illustration of a BLM in a Teflon-based chip with embedded Ti electrodes [PITH_FULL_IMAGE:figures/full_fig_p009_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: (a) Schematics of the procedure for fabricating Teflon-based chips. (b) Schematics of a fabricated Teflon-based chip. (c) (left) A photograph of a Teflon￾based chip having an aperture. (center) A photomicrograph of the Teflon-based chip around the aperture. (right) An FE-SEM image around the aperture [PITH_FULL_IMAGE:figures/full_fig_p010_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Effects of lateral voltages on transmembrane electric properties. (a) An example of current traces recorded at a transmembrane voltage of +100 mV with a BLM formed in a Teflon-based chip. (I) Without a connection between the Teflon-based chip and a DC power source (open state). (II) With a lateral voltage of 3 V, which was applied by a DC power source. (b) Relationships between lateral voltages and either … view at source ↗
Figure 5
Figure 5. Figure 5: Effect of a lateral voltage on ion channel currents recorded from a BLM formed in a Teflon-based chip. Transmembrane currents were recorded at a transmembrane voltage of +100 mV after the addition of proteoliposomes containing Nav1.5 channels. Example of current traces that were recorded when the lateral voltage of 2 V was (a) switched on, (b) switched off and (c) switched on again [PITH_FULL_IMAGE:figure… view at source ↗
read the original abstract

Artificial bilayer lipid membranes (BLMs), along with patch-clamped membranes, are frequently used for functional analyses of membrane proteins. In both methods, the electric properties of membranes are characterized by only one parameter, namely, transmembrane potential. Here the construction of a novel BLM system was reported, in which membrane voltages can be controlled in a lateral direction in addition to conventional transmembrane direction. A microaperture was fabricated in a Teflon film and Ti electrodes were evaporated around the aperture. BLMs were reproducibly formed in the aperture without being affected by the presence of the electrodes. The application of a lateral voltage induced no significant changes in the electric properties of the BLMs, such as baseline current, transmembrane resistance, and transmembrane capacitance. In contrast, lateral voltages clearly affected the activities of biological ion channels, suggesting that the lateral voltage might be a useful parameter for analyzing channel activities. The present Teflon-based system in which multidirectional voltages can be applied to BLMs represent a promising platform for the analysis of underlying functional properties of membrane proteins.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The manuscript describes construction of a Teflon-film microaperture BLM system with evaporated Ti electrodes surrounding the aperture. This enables simultaneous application of conventional transmembrane voltage and a novel lateral voltage. The authors report reproducible BLM formation unaffected by electrode presence, no significant change in baseline current, transmembrane resistance or capacitance upon lateral-voltage application, and clear effects on biological ion-channel activities, proposing lateral voltage as an additional useful parameter for membrane-protein analysis.

Significance. If the reported channel-activity changes are shown to arise from the intended lateral electric field rather than electrode artifacts, the platform would add a controllable experimental variable to BLM studies of membrane proteins. The reproducible formation and invariance of baseline electrical properties are methodologically useful observations. However, the absence of quantitative field characterization and artifact controls limits the strength of the mechanistic claim and therefore the immediate significance of the work.

major comments (2)
  1. [Abstract/Results] Abstract and Results: the central claim that lateral voltages 'clearly affected the activities of biological ion channels' is load-bearing for the utility argument, yet the abstract supplies no supporting data tables, figures, error bars, replicate numbers, or statistical tests. The full manuscript must include these quantitative results to substantiate differential channel effects.
  2. [Methods/Results] Methods/Results: the interpretation that observed channel changes are produced by the lateral electric field (rather than Ti-electrode side-effects such as local electrochemistry, redox products, Joule heating, or nonuniform gradients) rests on the statement that baseline BLM properties remain unchanged. No finite-element field maps, direct field measurements inside the aperture, temperature/pH sensors at the membrane, inert-electrode controls, or matched-heating experiments without net field are described. These controls are required to establish the claimed mechanism.
minor comments (1)
  1. [Abstract] Abstract, final sentence: subject-verb agreement error ('system ... represent' should read 'system ... represents').

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive comments, which have helped us improve the clarity and rigor of our manuscript. Below we provide point-by-point responses to the major comments.

read point-by-point responses

  1. Referee: [Abstract/Results] Abstract and Results: the central claim that lateral voltages 'clearly affected the activities of biological ion channels' is load-bearing for the utility argument, yet the abstract supplies no supporting data tables, figures, error bars, replicate numbers, or statistical tests. The full manuscript must include these quantitative results to substantiate differential channel effects.

    Authors: We agree that the abstract should better highlight the quantitative aspects of our findings to support the central claim. The full manuscript's Results section includes data from multiple experiments showing the effects on ion channels. We will revise the abstract to include a summary of the key quantitative results, such as the observed modulation of channel activity with replicate numbers and basic statistical information. We will also ensure that the figures in the Results section prominently display error bars and report the number of replicates and any statistical tests performed. revision: yes

  2. Referee: [Methods/Results] Methods/Results: the interpretation that observed channel changes are produced by the lateral electric field (rather than Ti-electrode side-effects such as local electrochemistry, redox products, Joule heating, or nonuniform gradients) rests on the statement that baseline BLM properties remain unchanged. No finite-element field maps, direct field measurements inside the aperture, temperature/pH sensors at the membrane, inert-electrode controls, or matched-heating experiments without net field are described. These controls are required to establish the claimed mechanism.

    Authors: The lack of change in baseline BLM properties upon lateral voltage application is our primary evidence against significant artifacts, as electrochemistry or heating would be expected to alter resistance or capacitance. We acknowledge that more direct controls would strengthen the mechanistic interpretation. In the revised manuscript, we will expand the Discussion to include a more thorough consideration of possible artifacts and how the unchanged properties mitigate them. We will also add a description of the electrode geometry to support the assumption of field application. However, performing finite-element simulations, direct field measurements, or additional control experiments with inert electrodes would require substantial new work beyond the scope of the current study; we will note this as a limitation and suggest it for future investigations. revision: partial

Circularity Check

0 steps flagged

No circularity: purely experimental methods paper with no derivations, predictions, or self-referential logic

full rationale

The paper reports fabrication of a Teflon-based BLM system with Ti electrodes for applying lateral voltages, followed by direct experimental observations that lateral voltage leaves baseline BLM properties unchanged but affects ion-channel activity. No equations, fitted parameters, predictions, ansatzes, or derivation chains exist. Claims rest on reproducible experimental formation of BLMs and measured electrical properties, with no self-citation load-bearing steps or reductions of results to inputs by construction. This is a standard experimental report whose central observations are independent of any looped logic.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

No free parameters, axioms, or invented entities are introduced; the work relies on standard assumptions of bilayer electrophysiology (lipid bilayers form insulating barriers, ion channels respond to transmembrane potential) without adding new mathematical constructs or postulated entities.

pith-pipeline@v0.9.0 · 5787 in / 1150 out tokens · 23695 ms · 2026-05-24T22:15:10.444347+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

18 extracted references · 18 canonical work pages

  1. [1]

    Neher, B

    E. Neher, B. Sakmann, Nature 1976, 260, 799

    work page 1976

  2. [2]

    Hamill, A

    O.P. Hamill, A. Marty, E. Neher, B. Sakmann, F.J. Sigworth, Pflugers Arch. 1981, 391, 85

    work page 1981

  3. [3]

    Sigworth, K.G

    F.J. Sigworth, K.G. Klemic, IEEE Trans. Nanobioscience 2005, 4, 121

    work page 2005

  4. [4]

    Montal, P

    M. Montal, P. Mueller, Proc. Natl. Acad. Sci. U. S. A. 1972, 69, 3561

    work page 1972

  5. [5]

    Hirano-Iwata, Y

    A. Hirano-Iwata, Y. Ishinari, H. Yamamoto, M. Niwano, Chem. An Asian J. 2015, 10, 1266

    work page 2015

  6. [6]

    Kamiya, T

    K. Kamiya, T. Osaki, K. Nakao, R. Kawano, S. Fujii, N. Misawa, M. Hayakawa, S. Takeuchi, Sci. Rep. 2018, 8, 17498

    work page 2018

  7. [7]

    Leptihn, J.R

    S. Leptihn, J.R. Thompson, J.C. Ellory, S.J. Tucker, M.I. Wallace, J. Am. Chem. Soc. 2011, 133, 9370

    work page 2011

  8. [8]

    Studer, S

    A. Studer, S. Demarche, D. Langenegger, L. Tiefenauer, Biosens. Bioelectron. 2011, 26, 1924

    work page 2011

  9. [9]

    Kalsi, A.M

    S. Kalsi, A.M. Powl, B.A. Wallace, H. Morgan, M.R.R. de Planque, Biophys. J. 2014, 106, 1650

    work page 2014

  10. [10]

    X. Han, A. Studer, H. Sehr, I. Geissbühler, M. Di Berardino, F.K. Winkler, L.X. Tiefenauer, Adv. Mater. 2007, 19, 4466

    work page 2007

  11. [11]

    Shim, L.Q

    J.W. Shim, L.Q. Gu, Anal. Chem. 2007, 79, 2207

    work page 2007

  12. [12]

    Sugawara, A

    M. Sugawara, A. Hirano, M. Rehák, J. Nakanishi, K. Kawai, H. Sato, Y. Umezawa, Biosens. Bioelectron. 1997, 12, 425

    work page 1997

  13. [13]

    Minami, M

    H. Minami, M. Sugawara, K. Odashima, Y. Umezawa, M. Uto, E.K. Michaelis, T. Kuwana, Anal. Chem. 1991, 63, 2787

    work page 1991

  14. [14]

    Miller, Ion Channel Reconsitution, New York, Plenum Press, 1986

    C. Miller, Ion Channel Reconsitution, New York, Plenum Press, 1986

    work page 1986

  15. [15]

    Mayer, J.K

    M. Mayer, J.K. Kriebel, M.T. Tosteson, G.M. Whitesides, Biophys. J. 2003, 85, 2684

    work page 2003

  16. [16]

    Klein, A

    G. Klein, A. Gardiwal, A. Schaefer, B. Panning, D. Breitmeier, Forensic Sci. Int. 2007, 171, 131

    work page 2007

  17. [17]

    Beyder, J.L

    A. Beyder, J.L. Rae, C. Bernard, P.R. Strege, F. Sachs, G. Farrugia, J. Physiol. 2010, 588, 4969

    work page 2010

  18. [18]

    Oshima, A

    A. Oshima, A. Hirano-Iwata, H. Mozumi, Y. Ishinari, Y. Kimura, M. Niwano, Anal. Chem. 2013, 85, 4363 Figure 1. A schematic illustration of a BLM in a Teflon-based chip with embedded Ti electrodes. Figure 2. (a) Schematics of the procedure for fabricating Teflon -based chips. (b) Schematics of a fabricated Teflon -based chip. (c) (left) A photograph of a T...

    work page 2013