Polymer-based Structures for Nanomedicine

Most published research has been carried out on polymer micelles. These can be formed by dissolving a block polymer in a solvent that is selective for one of the blocks, provided that a sufficiently high concentration of the polymer is used. Block 

The morphology, size and size distribution of micelles are very important in medical applications. These parameters can be determined by several techniques such as static light scattering for CMC, dynamic light scattering for size and size distributions. 

A third option for stabilising polymer micelles is to use block copolymers that have more than one stabilising and reactive group in the hydrophobic or core-forming block. This creates nanoparticles with considerably larger crosslinked cores. One example of such polymers is PEG-f -poly(butadiene) (PEG- -PB), where the butadiene block provides reactive handles that can be assembled into micelles of various morphologies, depending on the composition of the block copolymer. 

Sarmento and co-workers used alginate-cored nanoparticles that had been complexed with chitosan to produce a delivery system for insulin. These particles are negatively charged, and can complex insulin with 70% efficiency. Release of the protein is triggered by a change in pH. These particles have been orally administered to diabetic rats, and the serum glucose level has responded well [58]. 

Chitosan is another natural polymer, derived from the chitin produced by shellfish. It is highly water-soluble and is positively charged. Chitosan can be crosslinked in emulsion by glutaraldehyde reacting with the amino groups present on the chitosan backbone, to produce nanoparticular entities. Roy and co-workers used chitosan to create an oral formulation of a complex of plasmid deoxyribonucleic acid (DNA) 

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