| Abstract
| - We report the preparation of two-component microcapsules by a method termed core-mediated layer-by-layer (LbL) growth, which utilizes a core particle to mediate the formationof thin multilayer coatings on particles, followed by core removal. In the first (model) systemto demonstrate the process, multilayers were prepared on spherical, decomposable melamineformaldehyde (MF) particles by the alternating deposition of poly(styrenesulfonate) (PSS)from solution and MF originating from partial decomposition of the MF core (in-situ acid-decomposed MF, dMF) in a pH 4.0 buffer. The core-mediated LbL method was also appliedto a purely biocompatible system, consisting of a sodium alginate (Alg) coating on calciumphosphate (CaP) cores. Ultrathin, two-component PSS/dMF and Ca2+/Alg microcapsules wereprepared by decomposing the multilayer-coated cores using 0.1 M hydrochloric acid. Confocallaser scanning microscopy and transmission electron microscopy verified the formation ofultrathin multilayer capsules. Binding of a positively charged fluorescent molecule (doxorubicin) to the multilayer capsules showed that the fluorescence intensity of the capsulesregularly increased with increasing capsule wall thickness, confirming that the core mediatesPSS/dMF and Ca2+/Alg multilayer formation. Unlike conventionally prepared polyelectrolytecapsules from sacrificial cores, which are three component systems due to the presence ofdecomposed core material in the oppositely charged polyelectrolyte multilayers, the microcapsules reported here are two-component, as the core material itself forms one of themultilayer components.
- Polyelectrolyte (PE)-based multilayer capsules are prepared by a core-mediated layer-by-layer approach, which utilizes a core particle to promote the formation of thin multilayer coatings on particles. The partially dissolved core components (dCore) adsorb, regenerating the particle surface for further PE adsorption. Complete core decomposition and removal yields two-component multilayer capsules.
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