Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Diffusion01:12

Diffusion

176.3K
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...
176.3K
Diffusion01:21

Diffusion

5.7K
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...
5.7K
Passive Diffusion: Overview and Kinetics01:17

Passive Diffusion: Overview and Kinetics

1.8K
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...
1.8K
Facilitated Transport01:19

Facilitated Transport

14.5K
The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and hydrophilic regions, substances need to be able to transverse both regions. The hydrophobic area of membranes repels substances such as charged ions. Therefore, such substances need special membrane proteins to cross a membrane successfully. In  facilitated transport, also known as facilitated diffusion, molecules and ions travel across a...
14.5K
Facilitated Transport01:19

Facilitated Transport

129.4K
The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and hydrophilic regions, substances need to be able to transverse both regions. The hydrophobic area of membranes repels substances such as charged ions. Therefore, such substances need special membrane proteins to cross a membrane successfully. In  facilitated transport, also known as facilitated diffusion, molecules and ions travel across a...
129.4K
Facilitated Transport01:19

Facilitated Transport

8.1K
8.1K

You might also read

Related Articles

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

Sort by
Same author

Reactive capacitance of flat patches of arbitrary shape.

Physical review. E·2026
Same author

The geometric control of boundary-catalytic branching processes.

The Journal of chemical physics·2026
Same author

Correlation between the first-reaction time and the acquired boundary local time.

The Journal of chemical physics·2026
Same author

Long-Term Outcomes of Autologous Breast Reconstruction with or without Post-Mastectomy Radiotherapy.

Asian Pacific journal of cancer prevention : APJCP·2025
Same author

Note: Improved boundary homogenization for a sphere with an absorbing cap of arbitrary size.

The Journal of chemical physics·2025
Same author

Imperfect diffusion-controlled reactions on a torus and on a pair of balls.

The Journal of chemical physics·2025

Related Experiment Video

Updated: Apr 23, 2026

Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers
18:57

Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers

Published on: October 17, 2013

45.7K

Exploring diffusion across permeable barriers at high gradients. I. Narrow pulse approximation.

Denis S Grebenkov1, Dang Van Nguyen2, Jing-Rebecca Li3

  • 1Laboratoire de Physique de la Matière Condensée, CNRS - Ecole Polytechnique, F-91128 Palaiseau, France.

Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|September 21, 2014
PubMed
Summary

This study introduces a method to improve pulsed-gradient spin-echo (PGSE) signals by adjusting gradient intensity. This technique enhances the detection of nuclei diffusing across permeable barriers, optimizing diffusion measurements.

Keywords:
Bloch–Torrey equationDiffusionExchangePermeability

More Related Videos

A Method for Determination and Simulation of Permeability and Diffusion in a 3D Tissue Model in a Membrane Insert System for Multi-well Plates
10:33

A Method for Determination and Simulation of Permeability and Diffusion in a 3D Tissue Model in a Membrane Insert System for Multi-well Plates

Published on: February 23, 2018

27.9K
From Fast Fluorescence Imaging to Molecular Diffusion Law on Live Cell Membranes in a Commercial Microscope
15:10

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

Published on: October 9, 2014

11.0K

Related Experiment Videos

Last Updated: Apr 23, 2026

Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers
18:57

Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers

Published on: October 17, 2013

45.7K
A Method for Determination and Simulation of Permeability and Diffusion in a 3D Tissue Model in a Membrane Insert System for Multi-well Plates
10:33

A Method for Determination and Simulation of Permeability and Diffusion in a 3D Tissue Model in a Membrane Insert System for Multi-well Plates

Published on: February 23, 2018

27.9K
From Fast Fluorescence Imaging to Molecular Diffusion Law on Live Cell Membranes in a Commercial Microscope
15:10

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

Published on: October 9, 2014

11.0K

Area of Science:

  • Magnetic Resonance Imaging
  • Diffusion MRI
  • Biophysics

Background:

  • Pulsed-gradient spin-echo (PGSE) techniques are crucial for studying molecular diffusion.
  • Understanding diffusion across permeable barriers is vital in biological and material sciences.
  • Current methods may not fully capture the nuances of diffusion in complex environments.

Purpose of the Study:

  • To develop a novel protocol for enhancing PGSE signal contributions from nuclei diffusing across permeable barriers.
  • To derive an accurate formula for PGSE signals in systems with permeable barriers.
  • To investigate the sensitivity of the PGSE signal to barrier properties.

Main Methods:

  • Proposed adaptive variation of gradient intensity with diffusion time at a constant optimal b-value.
  • Derived an exact formula for the PGSE signal under narrow pulse approximation for 1D diffusion across a single permeable barrier.
  • Extended the formula to multiple permeable barriers and used numerical simulations.

Main Results:

  • The contribution of nuclei diffusing across permeable barriers to the PGSE signal can be enhanced.
  • A specific b-value maximizes the barrier contribution to the signal.
  • The PGSE signal is sensitive to barrier permeability and inter-barrier distance.

Conclusions:

  • The proposed adaptive gradient strategy optimizes PGSE signal acquisition for permeable barrier studies.
  • The derived formulas provide a quantitative framework for analyzing diffusion across barriers.
  • This approach has potential applications in surveying diffusion in 3D systems with permeable membranes.