Encapsulation of Photosensitizer into Multilayer Microcapsules by Combination of Spontaneous Deposition and Heat‐Induced Shrinkage for Photodynamic Therapy
MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
Abstract:
Annealing of PDADMAC/PSS multilayer microcapsules assembled on PSS‐doped CaCO3 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.
