Authors: A.S. Joseph, N.J. Brown, G. Battaglia
Affilation: University of Sheffield, United Kingdom
Pages: 371 - 374
Keywords: Polymersomes, fluorescence, HPLC, imaging
Nano-sized carriers are widely used as imaging tools. Quantification of the amount of carrier delivered provides useful informations in development and testing stages. This work describes a HPLC method to quantify fluorescent labelled polymersomes. Polymersomes are nanometer-sized vesicles made by the self-assembly of amphiphilc co- polymers in water . We use pH sensitive PMPC25-PDPA70 and PEO113 -PDPA70 co-polymers labelled with Rhodamine 6G. We analyse interactions of these two formulations with different cell populations using quantitative fluorescence microscopy imaging, fluorescence activated cell sorting (FACS) and HPLC quantification. A method is here developed to quantitatively recover and quantify polymersomes from cell lysate. Cellular studies are performed in static and in flow conditions, using mouse fibrosarcoma cells over-expressing different isoform of VEGF. Epifluorescence analysis showed that overtime there is an increase of up-take for both formulations. FACS analysis confirmed this trend . A significant difference was found between the two formulations in terms of percentage of cells up-taking fluorescent labelled polymersomes. The HPLC method we developed confirmed this difference and it also allowed to measure the quantity of labelled polymers up-taken. These results will provide the basis for the development of vesicles with targeting moieties.