Self-assembly in Nature

Nano

Self-assembly of amphiphilic molecules

spherical micelles cylindrical micelles nanotubes vesicles (liposomes)

Drug delivery systems Direct conjugation of drugs or therapeutic proteins to macromolecules such as polymers and proteins.

2. Encapsulation of hydrophobic drugs at the inside of the micelles or dendrimers

3. Entrapment of water-soluble drugs at the inside cavity of vesicles

The enhanced permeability and retention (EPR) effect Macromolecules cannot pass through the capillary walls of normal tissue. The entry of macromolecules into tumor tissue takes place in the capillaries where blood flow is diminished and nutrients transfer into the tissue. In contrast to the blood capillaries in most normal tissues, the endothelial layer of the capillaries in the tumor tissue is fenestrated and leaky so that macromolecules and other nanoparticles reach the malignant tissue. Tumor tissue generally has a defective lymphatic drainage system with the result that macromolecules are retained and can subsequently accumulate in solid tumors.