Matrix Polyelectrolyte Microcapsules:  New System for Macromolecule Encapsulation

Abstract

A new approach to fabricate polyelectrolyte microcapsules is based on exploiting porous inorganic microparticles of calcium carbonate. Porous CaCO3 microparticles (4.5−5.0 microns) were synthesized and characterized by scanning electron microscopy and the Brunauer−Emmett−Teller method of nitrogen adsorption/desorption to get a surface area of 8.8 m2/g and an average pore size of 35 nm. These particles were used as templates for polyelectrolyte layer-by-layer assembly of two oppositely charged polyelectrolytes, poly(styrene sulfonate) and poly(allylamine hydrochloride). Calcium carbonate core dissolution resulted in formation of polyelectrolyte microcapsules with an internal matrix consisting of a polyelectrolyte complex. Microcapsules with an internal matrix were analyzed by confocal Raman spectroscopy, scanning electron microscopy, force microscopy, and confocal laser-scanning fluorescence microscopy. The structure was found to be dependent on a number of polyelectrolyte adsorption treatments. Capsules have a very high loading capacity for macromolecules, which can be incorporated into the capsules by capturing them from the surrounding medium into the capsules. In this paper, we investigated the loading by dextran and bovine serum albumin as macromolecules. The amount of entrapped macromolecules was determined by two independent methods and found to be up to 15 pg per microcapsule.

Preserving Catalytic Activity and Enhancing Biochemical Stability of the Therapeutic Enzyme Asparaginase by Biocompatible Multilayered Polyelectrolyte Microcapsules

“…Enzyme-loaded microparticles formed by rapid mixing of Na 2 CO 3 and CaCl 2 in the presence of ScASNaseI exhibited an average size of 1−2 μm. We observed that microparticles of more homogeneous size and spherical morphology ( Figure S5) were obtained when lower than suggested 28,30 concentrations of Na 2 CO 3 and CaCl 2 were used. Therefore, the initial concentrations of Na 2 CO 3 and CaCl 2 were 0.15 M, rather than 1 M or 0.33 M, as reported before.…”

Polymeric multilayer capsules delivering biotherapeutics

“…For this purpose, emulsions [10,11] are used to encapsulate hydrophobic compounds -these are dissolved into an organic phase which is subsequently coated with a multilayer film -while porous inorganic templates can adsorb both hydrophilic as well as hydrophobic molecules in their pores. Mesoporous silica (SiO 2 ) [12][13][14] and calcium carbonate (CaCO 3 ) [15][16][17][18] microparticles have been used for this purpose. Mesoporous silica (Figure 2) benefits from the advantage that such templates can be obtained in a monodisperse state and that they are stable over the whole pH range which allows the use of polyelectrolyte solutions with acidic pH.…”

Nonstoichiometric Polyelectrolyte Complexes: Smart Nanoreactors for Alloy and Multimetallic Catalyst

“…Thus far, materials have been assembled on various templates such as CaCO 3 particles [6], melamine formaldehyde (MF) particles [7], silica particles [8], and so on. These approaches have some disadvantages such as formation of stable cores with certain surface properties, low incorporation efficiency and the harsh conditions usually used for core decomposition Manuscript (extreme pH or usage of organic solvents and oxidizing agents) which hinder the functional encapsulation of the macromolecules and confine usage of employed polymers for the other approaches [9].…”