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Polymersomes for intracellular delivery : mechanism of action and applications

The cell cytosol and the different subcellular organelles house the most important biochemical processes that control cell functions. Effective delivery of bioactive agents within cells is expected to have an enormous impact on both gene therapy and the future development of new therapeutic and/or diagnostic strategies based on single cell bioactive agent interactions. The main aim of this project was the evaluation of pH sensitive polymersomes made of poly(2-(methacryloyloxy)ethyl phosphorylcholine)-poly(2- (diisopropylamino)ethyl methacrylate) (PMPC-PDPA) block copolymer as a potential vector for intracellular delivery applications. Upon internalization through endocytosis, polymersomes were demonstrated to disassemble, triggering an increase in osmotic pressure within the endosomal compartments. This increase in pressure temporally destabilizes the endosomal membrane and facilitated the release of the polymersome payload within the cell cytosol. Biocompatibility of polymersomes and their uptake kinetics by different cells (both primary cells and cell lines) were assessed by Confocal Laser Scanning Microscopy (CLSM), Transmission Electron Microscopy (TEM), Flow Cytometry and Fluorescence Spectroscopy. The cellular-uptake kinetics was strongly dependent on the polymersomes surface chemistry, size and surface topology. The latter is controlled by the extent of polymer-polymer phase separation within the external envelope of the polymersome. Polymersomes were also successfully used as efficient vectors for the delivery of DNA, functional proteins and different imaging probes.
Date January 2011
CreatorsMassignani, Marzia
PublisherUniversity of Sheffield
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation

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