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Formulation of next-generation multicompartment microcapsules by reversible electrostatic attraction

: Neumann, Christian; Bacher, Lisa; Musyanovych, Anna; Tutus, Murat; Latnikova, Alexandra

Fulltext ()

Chemistry. A European journal 27 (2021), No.36, pp.93336-9341
ISSN: 0947-6539
ISSN: 1521-3765
Journal Article, Electronic Publication
Fraunhofer IMM ()
assembly; capsule; electrostatic interaction; polymers; programmable material

The combination of several active substances into one carrier is often limited due to solubility, stability and phase-separation issues. These issues have been addressed by an innovative capsule design, in which nanocapsules are assembled on the microcapsule surface by electrostatic forces to form a pH-responsive hierarchical capsule@capsule system. Here, melamine-formaldehyde (MF) microcapsules with a negative surface charge were synthesized and coated with a novel MF-polyethyleneimine (PEI) copolymer to achieve a positive charge of ζ=+28 mV. This novel coating procedure allows the electrostatic assembly of negatively charged poly-l-lactide (PLLA, ζ=−19 mV) and poly-(lactide-co-glycolide) (PLGA, ζ=−56 mV) nanocapsules on the microcapsule surface. Assembly studies at pH 7 gave a partial surface coverage of PLLA nanocapsules and full surface coverage for PLGA nanocapsules. The pH-responsive adsorption and desorption of nanocapsules was shown at pH 7 and pH 3.