まとめ
溶液の拡散率は微孔膜では,小さな分子であっても,著しく低下します. レンキン方程式は,分子拡散に対するこの阻害効果を正確に定量化します.
科学分野:
- 物理化学 物理化学
- マテリアルサイエンス 材料科学
- 化学工学は化学工学というものです.
背景:
- 毛細な材料における溶液の拡散を理解することは,濾過や薬剤投与などの用途において極めて重要です.
- 以前の研究では,不均一な毛孔構造が課題となり,拡散分析が複雑になった.
- 分子拡散の正確な決定には,明確に定義された多孔系が必要である.
研究 の 目的:
- 分子サイズの膜の毛穴内の水溶質の拡散に対する阻害効果を正確に定量化するために.
- 制御された膜システムを使用して,毛穴の大きさと分子拡散率の関係を調べる.
- 微孔膜における阻害された拡散に関する理論モデルを検証する.
主な方法:
- 均一でまっすぐなポールのミカ膜 (厚さ3~5μm,直径90~600μm) の製造.
- 分子直径5.2から43 Åの溶液の水分拡散率の測定.
- 液体フィルムの抵抗を補正して,孔内の固有分子拡散率を測定する.
主要な成果:
- 分子サイズが毛穴サイズに近づくにつれて,小さな分子の場合でも,拡散率の顕著な低下を示した.
- 溶解物分子が孔径よりはるかに小さい場合でも,拡散率が著しく阻害されていることが確認されました.
- 微孔膜内の溶液の拡散率の減少の定量的な推定値を取得しました.
結論:
- 均一な孔を持つミカ膜は,阻害された拡散を研究するための信頼できるモデルを提供します.
- 分子の大きさは,微孔膜内の拡散速度の決定的な役割を果たします.
- レンキン方程式は,微孔系における溶液拡散率の観測された減少を効果的にモデル化しています.
関連する概念動画
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...
Facilitated Diffusion
The plasma membrane, a critical structure in cellular biology, houses an array of transporters, or carrier proteins, interspersed within its lipid bilayer. These proteins play a crucial role in solute transport through facilitated diffusion, a form of passive diffusion that uses transporters to move the molecules across the membrane.
In this process, substrates such as organic compounds and ions interact with a transporter on one side, triggering conformational changes in proteins that enable...
In this process, substrates such as organic compounds and ions interact with a transporter on one side, triggering conformational changes in proteins that enable...
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...
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...
Facilitated Transport
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 membrane via...
Facilitated Transport
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 membrane via...
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...

