Melamine Formaldehyde Core Decomposition as the Key Step Controlling Capsule Integrity: Optimizing the Polyelectrolyte Capsule Fabrication

Gao, Changyou; Moya, Sergio; Donath, Edwin; Möhwald, Helmuth

doi:10.1002/1521-3935(20020401)203:7<953::aid-macp953>3.0.co;2-k

Cited by 58 publications

(50 citation statements)

References 9 publications

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“…[19] (2) The use of MF or PS microparticles are sacrificial core template suffers from remaining MF or PS oligomers/ polymers inside the capsule wall, [29,30] making the capsules unsuited as drug delivery system. The dissolution products of CaCO 3 are small ions which can easily permeate through the multilayer wall; moreover, they are non-toxic.…”

Section: Resultsmentioning

confidence: 99%

Stimuli‐Responsive Multilayered Hybrid Nanoparticle/Polyelectrolyte Capsules

Geest

Skirtach

Beer

et al. 2007

Macromol. Rapid Commun.

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Gold nanoparticles (AuNP) with carboxyl groups on their surface were used in combination with PAH for the layer‐by‐layer coating of CaCO3 microparticles, followed by the dissolution of the CaCO3 core. SEM, TEM, and confocal microscopy are used to characterize the hybrid nanoparticles/polyelectrolyte capsules. As the AuNP have carboxyl groups on their surface, their charge density is pH dependent; therefore, the capsules exhibit a pH‐dependent swelling and can be deconstructed both at low and high pH. By covalent cross‐linking of the carboxyl groups of the AuNP and the amino groups of the PAH, it is possible to suppress the pH‐responsive behavior. AuNP are used as activation centers using IR light and this ability is used to release encapsulated material from the nanoparticles/polyelectrolyte capsules as well as for the enhancement of detection and imaging of such capsules by Raman microspectrosopy.magnified image

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Section: Resultsmentioning

confidence: 99%

Stimuli‐Responsive Multilayered Hybrid Nanoparticle/Polyelectrolyte Capsules

Geest

Skirtach

Beer

et al. 2007

Macromol. Rapid Commun.

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“…In order to obtain capsules with good integrity, the freestanding multilayers of the microcapsules should be strong enough to resist the osmotic pressure during the core removal process [38,39]. Therefore, the ten-layer BSA BSA layer Number Fig.…”

Section: Hollow Protein Microcapsulesmentioning

confidence: 99%

pH-responsive protein microcapsules fabricated via glutaraldehyde mediated covalent layer-by-layer assembly

2008

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Bovine serum albumin (BSA) hollow microcapsules were fabricated through glutaraldehyde (GA) mediated covalent layer-by-layer assembly. The GA crosslinking of the adsorbed BSA on the colloidal particles enabled their surfaces to be covered by reactive aldehyde groups, which reacted with BSA molecules to result in another covalently linked layer. Repeating of this cycle could then yield particles coated with BSA multilayers. Hollow microcapsules well dispersed in water were obtained after core removal. The good integrity and morphology of the BSA capsules were confirmed and characterized by confocal laser scanning microscopy, scanning electron microscopy and scanning force microscopy. The obtained BSA microcapsules possess reversible pH response, i.e., the capsules are permeable to macromolecules below pH 4 or above pH 10, while impermeable in between. The mechanisms of permeability transition were discussed. Using this property, dextran, with a molecular weight of~155 kDa, was successfully loaded.

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“…For capsule fabrication PEMs are assembled on top of sacrificial colloids, which are dissolved after the LbL coating [15,16]. After core dissolution, the PEM remains, forming an empty closed shell, which can be loaded with different materials [17,18]. Besides the loading of the capsule interior, materials for delivery i.e.…”

Section: Introductionmentioning

confidence: 99%