Anisotropic Micro‐ and Nano‐Capsules

Abstract

In this work, we introduce anisotropically shaped, ultrathin micro- and nano-capsules fabricated by layer-by-layer approach. The original cubic and tetrahedral shapes of the template particles were replicated to produce hollow capsules with well-defined edges. Introducing tannic acid as a component of LbL shells resulted in enhanced chemical stability of these hollow polymer structures under a wide pH range due to high pK(a) value. Computational studies demonstrated increased mechanical stability of the anisotropic capsules under osmotic pressure variation due to sharp edges and vertices acting as a reinforcing frame in contrast to spherical microcapsules that undergo random buckling.

Anisotropic polydopamine capsules with an ellipsoidal shape that can tolerate harsh conditions: efficient adsorbents for organic dyes and precursors for ellipsoidal hollow carbon particles

“…16,18,19 Furthermore, the non-spherical shape of the capsules oen lose aer removing the templates due to high residual stresses or osmotic pressures. 16,18,19 In terms of such challenges, PDA coating is valuable due to its capability to form a conformal coating layer on particulate templates with any kinds of shapes. 5,6,[9][10][11][12] Even so, PDA capsules with an anisotropic shape have barely been reported.…”

Colloidal micro- and nano-particles as templates for polyelectrolyte multilayer capsules

“…Thus, future trends in particle-directed drug delivery are toward novel methods of synthesis and elaboration of anisotropic particles which in specific cases resemble natural vehicles like bacteria [117]. Not only particles of certain shapes can be used as delivery system, but also capsules templated on specifically shaped particles would be beneficial to certain applications [118,119]. The flexibility of polyelectrolytes molecules allows reproducing a number of capsule shapes after decomposition of the initial solid cores [119][120][121].…”

“…Not only particles of certain shapes can be used as delivery system, but also capsules templated on specifically shaped particles would be beneficial to certain applications [118,119]. The flexibility of polyelectrolytes molecules allows reproducing a number of capsule shapes after decomposition of the initial solid cores [119][120][121]. Shchepelina et al compared the morphology, mechanical properties, and permeability of hydrogen-bonded layer-by-layer (LbL) microcapsule shells assembled on squared cadmium carbonate particles against the same shells assembled on spherical silica.…”

Release from Polyelectrolyte Multilayer Capsules in Solution and on Polymeric Surfaces

“…[26], [27] The flexibility of polyelectrolytes allows keeping different shapes of the formed multilayer capsules after decomposition of the sacrificial solid templates. [28] Shchepelina et al compared morphology, mechanical properties, and permeability of hydrogen-bonded LbL microcapsule shells assembled on square cadmium carbonate against the same shells assembled on spherical silica. [23] The patterned template-assisted assembly of the cubic micro-particles driven by the competing capillary, Coulombic, and van der Waals forces in comparison with the traditional spherical colloidal microparticles had been studied by Lisunova et al [29] Doxorubicin cubes have been identified as effective carriers of doxorubicin in cells, [30] while cubic shape has been reported to be effective for the interaction of LbL polymeric particles with breast cancer cells.…”