Related Experiment Video
Updated: May 18, 2026
07:57
Taking Advantage of Reduced Droplet-surface Interaction to Optimize Transport of Bioanalytes in Digital Microfluidics
Published on: November 10, 2014
Fluctuating noise drives Brownian transport.
Yoshihiko Hasegawa1, Masanori Arita
1Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan. hasegawa@cb.k.u-tokyo.ac.jp
Journal of the Royal Society, Interface
|September 15, 2012
Summary
Stochastic intensity noise influences Brownian ratchet transport. Optimal noise correlation, observed in both simulations and gene expression, highlights environmental noise
Area of Science:
- Physics
- Biophysics
- Statistical Mechanics
Background:
- Brownian ratchets are essential for directed transport in biological and physical systems.
- Stochastic noise can significantly impact the efficiency of molecular motors and transport processes.
Purpose of the Study:
- To investigate the transport properties of a Brownian ratchet under stochastic intensity noise.
- To analyze the influence of noise characteristics on transport efficiency in both overdamped and underdamped regimes.
Main Methods:
- Analytical solution using the matrix-continued fraction method for the overdamped regime.
- Monte Carlo simulations for the underdamped regime.
- Analysis of noise time-correlation properties.
Main Results:
- A maximum current was observed in the overdamped case when noise intensity fluctuated on intermediate timescales.
- Similar noise-induced transport optimization effects were found in the underdamped regime.
- The optimal noise time-correlation matched experimental observations in Escherichia coli gene expression.
Conclusions:
- Environmental noise plays a crucial role in molecular transport mechanisms.
- Understanding noise dynamics is key to optimizing Brownian ratchet performance.
- The findings have implications for molecular biology and nanotechnology.
Related Concept Videos
01:21Entropy Changes Accompanying Specific Processes
Entropy, a measure of disorder in a system, changes during phase transitions like freezing or boiling. At the transition temperature Ttrs, where two phases are in equilibrium, the phase transition is a reversible process. The entropy change can be calculated from a substance's enthalpy of transition using the equation ΔStrs = ΔtrsH /Ttrs.When a perfect gas expands isothermally from one volume to another, entropy increases logarithmically with volume. Conversely, isothermal compression results...
01:16Non-equilibrium in the Cell
An important concept in studying metabolism and energy is that of chemical equilibrium. Most chemical reactions are reversible. They can proceed in both directions, releasing energy into their environment in one direction, and absorbing it from the environment in the other direction. The same is true for the chemical reactions involved in cell metabolism, such as the breaking down and building up of proteins into and from individual amino acids, respectively. Reactants within a closed system...
01:17Passive 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...
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...
01:24Protein 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...
01:21Carrier 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:
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:
01:19Membrane Asymmetry Regulating Transporters
Enzymes like flippase, floppase, and scramblase transfer phospholipids from one layer to another in the membrane, thereby affecting membrane asymmetry.
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...