Hydrosomes, novel thermosensitive gel-containing polymersomes

Novel thermosensitive gel-containing polymersomes (hydrosomes) were prepared by incorporating poly(N-isopropylacrylamide), PNIPAAm, into polymersomes based on poly(ethylene glycol)-b-poly(d,l-lactide). These hydrosomes are potential novel carriers for anticancer drugs and proteins. Hydrosomes with a size of 100–200 nm as determined with high resolution SEM, were prepared by injecting a solution of the polymer and PNIPAAm in THF into water. Giant hydrosomes containing fluorescein labeled PNIPAAm were prepared using CHCl3 as the organic phase. The presence of the gel inside the polymersomes was shown by confocal laser scanning microscopy. Release of fluorescein isothiocyanate tagged dextran (FD, FITC-dextran, Mw 4000 g/mol) reveals that hydrosomes have acquired a more sustained release profile in comparison with empty polymersomes at 37 °C for 30 days, with low initial burst effect.