Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Diffusion

Diffusion

Diffusion is the passive movement of substances down their concentration gradients—requiring no expenditure of cellular energy. Substances, such as molecules or ions, diffuse from an area of high concentration to an area of low concentration in the cytosol or across membranes. Eventually, the concentration will even out, with the substance moving randomly but causing no net change in concentration. Such a state is called dynamic equilibrium, which is essential for maintaining overall...

Diffusion

Diffusion

Diffusion is a type of passive transport. In passive transport, a substance tends to move from an area of high concentration to an area of low concentration until the concentration is equal across the space. For example, take the diffusion of substances through the air. When someone opens a perfume bottle in a room filled with people, the perfume is at its highest concentration in the bottle and is at its lowest at the edges of the room. The perfume vapor will diffuse, or spread away, from the...

Carrier Transport

Carrier Transport

The generation of electrical current in semiconductors is fundamentally driven by two mechanisms: drift and diffusion. These processes are essential for the functionality and performance of semiconductor-based devices.
Drift Current:
The drift of charge carriers is started by an external electric field (E). Charged particles, such as electrons and holes, experience an acceleration between collisions with lattice atoms. For electrons, this results in a drift velocity (vd) given by:

Protein Diffusion in the Membrane

Protein Diffusion in the Membrane

Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...

Passive Diffusion: Overview and Kinetics

Passive Diffusion: Overview and Kinetics

Passive diffusion is a critical process that allows small lipophilic drugs to cross the cell membrane along a concentration gradient. This mechanism's efficiency depends on four primary factors: the membrane's surface area, the drug's lipid-water partition coefficient, the concentration gradient, and the membrane's thickness.
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...

Reynolds Transport Theorem

Reynolds Transport Theorem

The Reynolds transport theorem provides a framework to relate the time rate of change of an extensive property within a system to that in a control volume, which is crucial for analyzing fluid dynamics. Extensive properties, such as mass, velocity, acceleration, temperature, and momentum, can be expressed in terms of the mass of a fluid portion. These properties are called extensive because they depend on the system's size, while intensive properties are their corresponding values per unit mass.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Epidemiology of dog bite and strike related hospital admissions in Scotland, 1997 to 2022.

Public health·2025

Same author

Inflammation dynamically regulates steroid hormone metabolism and action within macrophages in rheumatoid arthritis.

Journal of autoimmunity·2024

Same author

Oral 11β-HSD1 inhibitor AZD4017 improves wound healing and skin integrity in adults with type 2 diabetes mellitus: a pilot randomized controlled trial.

European journal of endocrinology·2022

Same author

Evaluation of Locoregional Recurrence Patterns Following Adjuvant (Chemo)Radiotherapy for Oral Cavity Carcinoma.

Clinical oncology (Royal College of Radiologists (Great Britain))·2019

Same author

Locus of control is associated with tobacco and alcohol consumption in young adults of the Avon Longitudinal Study of Parents and Children.

Royal Society open science·2019

Same author

Simultaneous parameter estimation and variable selection via the logit-normal continuous analogue of the spike-and-slab prior.

Journal of the Royal Society, Interface·2019

Same journal

Heterogeneous binding of SARS-CoV2 fusion peptide on complex cellular membranes enhances its fusogenicity.

Biophysical journal·2026

Same journal

Tau protein differentially affects Piezo1 and Kir2.1 channels in brain capillary endothelial cells.

Biophysical journal·2026

Same journal

Emergent Intercellular Junction Stability during Cyclic Tissue Loading.

Biophysical journal·2026

Same journal

Enhanced-Sampling Simulations Reveal Distinct Intermediates in SARS-CoV-2 FSE Pseudoknot Interconversion.

Biophysical journal·2026

Same journal

Structure-based simulations of the full Flock House virus capsid reveal pathways and energetics of an infection-critical peptide externalization event.

Biophysical journal·2026

Same journal

Quantifying the Peripheral Surface Information Entropy from Conformational Ensembles of Globular Protein-Peptide Complexes.

Biophysical journal·2026

See all related articles

Search research articles

Related Experiment Video

Updated: Jun 25, 2026

The Diffusion of Passive Tracers in Laminar Shear Flow

The Diffusion of Passive Tracers in Laminar Shear Flow

Published on: May 1, 2018

Tracer diffusion and unidirectional fluxes.

P F Curran¹, A E Taylor, A K Solomon

¹Biophysical Laboratory, Harvard Medical School, Boston, MA 2115, USA; and Department of Physiology, Yale University School of Medicine, New Haven CT, 06510, USA.

Biophysical Journal

|February 13, 2009

Summary

This summary is machine-generated.

Cross-coefficients minimally impact tracer diffusion and flux estimation in biological systems. Tracer flow measurements accurately predict bulk substance flow, crucial for understanding transport mechanisms.

More Related Videos

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

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

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

Published on: October 9, 2014

Related Experiment Videos

Last Updated: Jun 25, 2026

The Diffusion of Passive Tracers in Laminar Shear Flow

The Diffusion of Passive Tracers in Laminar Shear Flow

Published on: May 1, 2018

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

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

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

Published on: October 9, 2014

Area of Science:

Biophysical chemistry
Membrane transport
Chemical kinetics

Background:

Understanding solute transport across membranes is vital in biology and medicine.
Tracer diffusion studies are common but can be complicated by cross-coefficients.
Accurate estimation of unidirectional fluxes is essential for quantitative analysis.

Purpose of the Study:

To evaluate the influence of cross-coefficients on tracer diffusion.
To assess the accuracy of estimating unidirectional fluxes using tracer flow data.
To determine the conditions under which tracer flow reliably predicts bulk substance flow.

Main Methods:

Analysis of existing experimental data on tracer diffusion.
Mathematical modeling of tracer and unlabelled substance interactions.
Comparison of tracer flow measurements with bulk substance flow predictions.

Main Results:

Cross-coefficients have negligible effects on tracer diffusion and flux estimation for common biological solutes (urea, alanine, sodium, chloride) at relevant concentrations.
In free solution or nonselective membranes, tracer flow accurately predicts bulk substance flow.
The prediction accuracy for bulk substance flow is within a few percent.

Conclusions:

Tracer flow measurements are reliable for quantifying bulk substance transport under typical biological conditions.
The impact of cross-coefficients is minimal, simplifying the interpretation of tracer studies.
This validates the use of tracer techniques for studying transport phenomena in biological systems.