| STUDY |
Authors are investigating the utilization of polyelectrolyte multilayers to fabricate nanoengineered core-shell structures. "Different templates, such as organic and inorganic colloid particles, protein aggregates, biological cells, and drug crystals, can be used as cores to assemble multilayer films. "The size of the cores ranges from 50 nm to tens of micrometers. The shells can be fabricated from a variety of compounds such as charged and noncharged polymers, biopolymers, lipids, multivalent dyes, and inorganic nanoparticles." The group has shown that the permeability of the shells and the release of the encapsulated materials can be controlled and modified by pH, ionic strength, and solvents. Authors used layer-by-layer assembly of oppositely charged polyelectrolytes--sodium poly(styrene sulfonate) and poly(allylamine hydrochloride)--to coat fluorescein particles. Dyes such as fluorescein are model compounds for a variety of drugs. The group used fluorescence spectroscopy to monitor the dissolution of the fluorescein core in a pH 8 buffer solution and showed that the rate of release of the fluorescein from the capsule is a function of the number of assembled polyelectrolyte layers. "This system provides an elegant means of studying the permeability of polyelectrolyte multilayers," the authors noted. They pointed out that the assembly of shells by the layer-by-layer technique opens up new pathways for biotechnological applications, where the controlled and sustained release of a substance is required. "Many problems connected with drug formulation, release, and delivery and controlling the concentration in an organism and periodicity of its reception might be solved by the formation of shells on precipitates and nanocrystals," they concluded |
| UPDATE | 05.02 |
| AUTHOR | This data is not available for free |
| LITERATURE REF. | This data is not available for free |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |