A micelle is a tiny, ball-like cluster of molecules (like soap or lipids) that form spontaneously in water, with their water-hating (hydrophobic) tails pointing inward and their water-loving (hydrophilic) heads facing outward, creating a stable, oil-like core that can trap other substances, crucial for tasks like cleaning, fat digestion, and modern drug delivery.
Structure & Formation
- Amphiphilic Molecules: Micelles are made from surfactants (like soaps) or lipids, which have both water-attracting (hydrophilic) heads and oil-attracting (hydrophobic) tails.
- Self-Assembly: In water, these molecules arrange themselves into spheres (or sometimes cylinders/ellipsoids) to minimize contact between their hydrophobic tails and water, forming a stable core.
- Reverse Micelles: In oily liquids, the structure reverses, with hydrophilic heads facing inward and hydrophobic tails facing outward.
Key Functions & Applications
- Cleaning: Soap micelles trap oily dirt and grease in their hydrophobic core, allowing it to be washed away with water.
- Digestion: In the small intestine, micelles transport fats, fat-soluble vitamins, and cholesterol to the intestinal wall for absorption.
- Drug Delivery: In medicine, artificial micelles (often polymeric) are used to encapsulate and deliver poorly water-soluble drugs to target cells, improving their solubility and effectiveness.
- Colloidal Systems: They form stable dispersions, important in many industrial processes and biological systems, acting as simple models for cell membranes.
Key Types
- Classic Soap Micelles: Formed from fatty acid salts (soaps).
- Lipid Micelles: Formed by phospholipids, vital in biology.
- Polymeric Micelles: Engineered from amphiphilic block copolymers for specific drug delivery, offering stability and controlled release.
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