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Related Experiment Video

Updated: Jun 1, 2026

Spot Variation Fluorescence Correlation Spectroscopy for Analysis of Molecular Diffusion at the Plasma Membrane of Living Cells

Spot Variation Fluorescence Correlation Spectroscopy for Analysis of Molecular Diffusion at the Plasma Membrane of Living Cells

Published on: November 12, 2020

Proton diffusion along biological membranes.

E S Medvedev¹, A A Stuchebrukhov

¹Institute of Problems of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russian Federation.

Journal of Physics. Condensed Matter : an Institute of Physics Journal

|May 27, 2011

Summary

Biological surfaces act as proton-collecting antennas, enhancing proton flux through coupled 2D+3D diffusion. This model explains proton travel along lipid membranes and predicts flux dependence on buffer concentration.

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From Fast Fluorescence Imaging to Molecular Diffusion Law on Live Cell Membranes in a Commercial Microscope

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Last Updated: Jun 1, 2026

Spot Variation Fluorescence Correlation Spectroscopy for Analysis of Molecular Diffusion at the Plasma Membrane of Living Cells

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From Fast Fluorescence Imaging to Molecular Diffusion Law on Live Cell Membranes in a Commercial Microscope

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Published on: October 9, 2014

Area of Science:

Biophysics
Surface Chemistry

Background:

Biological surfaces facilitate proton retention and lateral diffusion.
Proton movement involves coupled surface (2D) and bulk (3D) diffusion.

Purpose of the Study:

Review a phenomenological model for proton diffusion on biological surfaces.
Apply the model to experimental data from lipid bilayers and vesicles.

Main Methods:

Phenomenological modeling of coupled 2D+3D proton diffusion.
Analysis of proton exchange regimes (fast and slow).
Evaluation of antenna radius and amplification coefficients.

Main Results:

The model explains long-range proton travel (micrometers) on lipid membranes.
Calculated surface diffusion coefficient for vesicles: 1 × 10⁻⁵ cm²/s.
Explained kinetic curves of pH-sensitive dyes and effects of membrane composition.

Conclusions:

Biological surfaces act as proton-collecting antennas, significantly enhancing proton flux.
The model accurately describes proton diffusion dynamics and predicts experimental observations.
Proton transport on membranes is influenced by surface properties and buffer concentration.