Encapsulation of photosensitizer into multilayer microcapsules by combination of spontaneous deposition and heat-induced shrinkage for photodynamic therapy.

Yuanyuan Han, Jing Bu, Yuying Zhang, Weijun Tong, Changyou Gao

Index: Macromol. Biosci. 12(10) , 1436-42, (2012)

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Abstract

Annealing of PDADMAC/PSS multilayer microcapsules assembled on PSS-doped CaCO(3) particles at 80 °C for 30 min reduces their size dramatically from 6.9 ± 0.3 to 3.1 ± 0.5 µm. Methylene blue molecules are encapsulated by spontaneous deposition and post-annealing with a concentration of 22 mg · mL(-1), which is 1000 times higher than the feeding value. The unreleased MB molecules are retained stably for a long time, which are then protected by the capsules against reductive enzymes and keep their photodynamic activity. The viability of HeLa cells incubated with the MB-loaded capsules decreases sharply from ≈ 75 (dark cytotoxicity) to ≈ 20% after irradiation with a laser at 671 nm and 60 J · cm(-2) for 75 s.Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.