Application of Polymerized Vesicles

Apart from the possible use of polymerized vesicles as stable models for biomembranes (Sect. 4) there may be a variety of different applications. Polymerized surfactant vesicles have been proposed to act as antitumor agents on a cellular level33 in analogy to the action of the immune system of mammals against tumor cells 85). Polymerized vesicles open the door to chemical membrane dissymmetry 22) which in turn, may lead to enhanced utility in photochemical energy transfer84 (solar energy conversion, artificial photosynthesis). The utilization of unpolymerized lipo- 

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Several comprehensive reviews on polymerizable lipids and supramolecular structures derived from them appeared between 1985 and 2002 [3,25-31], Consequently, this review focuses on developments in this field during 2000-2008. These include synthesis of new types of polymerizable lipids, creation and characterization of novel poly(lipid) membrane systems, and applications of polymerized vesicles and membranes in chemical sensing, separations science, drug delivery, materials biocompatibility, and other fields. 

Polymeric vesicles could be of better use for such an antitumor therapy on a cellular level, since they have at least one of the properties required, namely an extraordinary membrane stability. For a successful application, however, the simple systems prepared so far must be varied to a great extent, because the stability of a model cell membrane is not the only condition to be fulfilled. Besides stability and possibilities for cell recognition as discussed above the presence of cell membrane destructing substances such as lysophospholipids is necessary. These could e.g. be incorporated into the membrane of stabilized liposomes without destruction of the polymeric vesicles. There have already been reports about thekilling of tumor cells by synthetic alkyl lysophospholipids (72). 

All the observed morphologies (including the phase separated parachutes and necklaces) are potentially useful in a variety of applications. German et al. have proposed that necklaces composed of a variety of different polymeric beads could be useful as controlled release materials [20]. Most importantly, the implications of polymerization in vesicles can reveal more about the fundamental properties of vesicles as well as provide information about polymerization reactions in confined media. 

There are many different applications of the DLS technique. The DLS method has been u.sed to determine the size of polymer lattices and resins and to monitor the grow th of particles during processes such as emulsification and polymerization. Micelles and microemulsions have been studied by DL.S methods. DLS is also widely applicable to the investigation of biopolymers and biocolloids. It has been used to study natural and synthetic polypeptides, nucleic acids, ribosomes, vesicles, viruses, and muscle fibers. 

Apart from their morphological diversity, polymer vesicles have been at the focus of extensive research also because of their potential applications, especially in medical fields. These kinds of applications usually exploit the unique ability of polymersomes to encapsulate hydrophilic compounds within the core and, at the same time, hydrophobic and amphiphilic molecules within the membrane. This feature combined with the enhanced mechanical properties of polymeric membranes renders them ideal delivery devices. As a result, polymer vesicles have been extensively utilised in drug delivery, gene therapy, protein delivery, medical imaging, cancer diagnosis and therapy, etc. [48-54]. 

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