Polymer microcapsules as mobile local pH-sensors

Oliver Kreft, Almudena Muñoz Javier, Gleb B. Sukhorukov, Wolfgang J. Parak

Research output: Contribution to journalArticlepeer-review

212 Citations (Scopus)


Polyelectrolyte microcapsules have been loaded with a pH-sensitive, high molecular weight SNARF-1-dextran conjugate. SNARF-1 exhibits a significant pH-dependent emission shift from green to red fluorescence under acidic and basic conditions, respectively. The unique spectral properties of the dye were maintained after the encapsulation. By investigating both human breast cancer cells and fibroblasts, we were able to follow the pH change of the local environment of SNARF-1-filled capsules during the transition from the alkaline cell medium to the acidic endosomal/lysosomal compartments. The incorporation of magnetite nanoparticles and an additional pH-insensitive fluorophore within the capsule shell resulted in a novel type of sensor system based on multifunctional polymer capsules.

Original languageEnglish
Pages (from-to)4471-4476
Number of pages6
JournalJournal of Materials Chemistry
Issue number42
Publication statusPublished - 2007
Externally publishedYes


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