Polyelectrolyte microcapsules

Stein EW, Volodkin DV, McShane Ml, Sukhomkov GB. Real-time assessment of spatial and temporal coupled catalysis within polyelectrolyte microcapsules containing coimmobilized glucose oxidase and peroxidase. Biomacromolecules 2006 7 710-719. 

Zhu H, McShane MJ. Macromolecule encapsulation in diazoresin-based hollow polyelectrolyte microcapsules. Langmuir 2005, 21, 424-430. 

Furthermore, a rigid glass bead can be glued to a tipless cantilever, and used as a force probe to compress single particles, such as Jurket T lymphomas cells (Lulevich et al., 2006) and polyelectrolyte microcapsules (Lulevich et al., 2003). 

Peyratout CS, Dahne L (2004) Tailor-made polyelectrolyte microcapsules from multilayers to smart containers. Angew Chem Int Ed 43 3762-3783... 

Volodkin DV, Petrov Al, Prevot M et al (2004) Matrix polyelectrolyte microcapsules new system for macromolecule encapsulation. Langmuir 20 3398-3406... 

Lu Z, Prouty MD, Guo Z et al (2005) Magnetic switch of permeability for polyelectrolyte microcapsules embedded with Co Au nanoparticles. Langmuir 21 2042-2050... 

Hu S-H, Tsai C-H, Liao C-F et al (2008) Controlled rupture of magnetic polyelectrolyte microcapsules for drug delivery. Langmuir 24 11811-11818... 

Stable polyelectrolyte microcapsules were produced by means of the layer-by-layer adsorption of protamine and alginic acid on the surface of calcium carbonate microcores followed by the cores dissolution at low pH. The capsules obtained were investigated by atomic force microscopy and confocal laser scanning microscopy. 

T. Sun, C. Bemabini and H. Morgan, Single-colloidal particle impedance spectroscopy complete equivalent circuit analysis of polyelectrolyte microcapsules, Langmuir, DOT 10.1021/la903609u (2009). 

Fig. 7 Schematic representation of the procedure for encapsulating enzyme in polyelectrolyte microcapsules using MS spheres as templates (I) enzyme immobilization in MS spheres (II) LbL assembly of oppositely charged polyelectrolytes (PE) (III) MS sphere template dissolution using buffered hydrofluoric acid (IV) enzyme encapsulation in a polyelectrolyte microcapsule and (V) enzyme release via altering the shell permeability by pH or salt changes. Reprinted with permission from Advanced Materials [76]...

Tong W, Gao C, Mohwald H (2006) Stable weak polyelectrolyte microcapsules with pH-responsive permeability. Macromolecules 39 335-340... 

Wattendorf U, Kreft O, Textor M, et al. (2008) Stable stealth function for hollow polyelectrolyte microcapsules through a poly(ethylene glycol) grafted polyelectrolyte adlayer. Biomacromolecules 9 1(X)-108... 

Tiourina OP, Antipov AA, Sukhorukov GB, et al. (2001) Entrapment of alpha-chymotrypsin into hollow polyelectrolyte microcapsules. Macromol Biosci 1 209-214... 

Ghan R, Shutava T, Patel A, et al. (2004) Enzyme-catalyzed polymerization of phenols within polyelectrolyte microcapsules. Macromolecules 37 4519-4524... 

Furthermore, porous CPs (e.g., polypyrrole, polyanUine) films have been used as host matrices for polyelectrolyte capsules developed from composite material, which can combine electric conductivity of the polymer with controlled permeability of polyelectrolyte shell to form controllable micro- and nanocontainers. A recent example was reported by D.G. Schchukin and his co-workers [21]. They introduced a novel application of polyelectrolyte microcapsules as microcontainers with a electrochemically reversible flux of redox-active materials into and out of the capsule volume. Incorporation of the capsules inside a polypyrrole (PPy) film resulted in a new composite electrode. This electrode combined the electrocatalytic and conducting properties of the PPy with the storage and release properties of the capsules, and if loaded with electrochemical fuels, this film possessed electrochemically controlled switching between open and closed states of the capsule shell. This approach could also be of practical interest for chemically rechargeable batteries or fuel cells operating on an absolutely new concept. However, in this case, PPy was just utilized as support for the polyelectrolyte microcapsules. 

C. Dejugnat and G.B. Sukhorukov, PH-responsive properties of hollow polyelectrolyte microcapsules templated on various cores, Langmuir, 20(17), 7265-7269 (2004). 

Vergaro, V., Scarlino, R, Bellomo, C., Rinaldi, R., Vergara, D., Maffia, M., Baldassarre, F. et al. Drug-loaded polyelectrolyte microcapsules for sustained targeting of cancer cells. Adv. Drug Deliv. Rev. 2011, 63 (9), 63847-63864. 

Aim of this worit was to demonstrate a particular example of a sensor system, which combines catalytic activity for urea and at the same time, enabling monitoring enzymatic reaction by optical recording. The proposed sensor system is based on multilayer polyelectrolyte microcapsules containing urease and a pH-sensitive fluorescent dye, which translates the enzymatic reaction into a fluorescendy registered signal. 

THE DEPENDENCE OF PROTEINS DISTRIBUTION WITHIN POLYELECTROLYTE MICROCAPSULES ON PH OF THE MEDIUM... 

Thus, if the pH is less than the isoelectric point (p/ 4.7), a protein is positively charged, while the inner layer of polyelectrolyte microcapsules is presented as a polycation, the protein molecules are distributed throughout its volume. Protein molecules lose their chaige values near the isoelectric point and are concentrated in the wall space of the capsule due to hydrophobic interactions with a polyelectrolyte shell. If the polyanion PSS was nsed as the first layer in the formation of a shell, the protein at all pH valnes in the range stndied was located in the wall space (Figure 3). We attribute this to the electrostatic interaction between protein molecules and the polyelectrolyte at low pH and hydrophobic interactions in the region of the isoelectric point. 

FIGURE 3 Electron micrograph of ultrathin sections of polyelectrolyte microcapsules containing ferritin at pH 2. The polyelectrolyte shell of the composition is (PSS/PAA)3. 

The distribution of proteins inside polyelectrolyte microcapsules depend on charges of protein and of inner polyelectrolyte layer. 

In another study, thiol-funaionalized HA was used for the preparation of disulfide aoss-linked nanogels with physically entrapped green fluorescence protein siRNA by an inverse w/o emulsion approach. The same group prepared disulfide-cross-linked HA miaogds and prepared shell cross-linked HA/polylysine layer-by-layer polyelectrolyte microcapsules through layer-by-layer approach followed by the removal of the reducible HA miaogd cores with dithiothreitol (DTT). ... 

O. P. Tiourina, A. A. Antipov, G. B. Sukhorukov, N. L. Larionova, Y. Lvov, H. Mohwald, Entrapment of a-chymotrypsin into hollow polyelectrolyte microcapsules, Macromolecular Bioscience 2001,1, 209. 

Use of the LbL assembly is not limited to fabrication of thin films on fiat substrates. It can be applied to a microsized colloidal particle core to prepare hollow capsules, which are expected to be highly useful for DBS applications. In this innovative strategy, LbL films are assembled sequentially on a colloidal core similar to the conventional LbL assemblies on a fiat substrate. Destruction of the central particle core after completion of the LbL assembly results in formation of hollow capsule structures. Figure 2.2.7 illustrates one example to prepare a biocompatible polyelectrolyte microcapsule with DNA encapsulation by Lvov and coworkers [15]. In their approach, water-insoluble DNA/spermidine complexes were... 

Self-assembly of oppositely charged polyelectrolytes is a powerful tool for the fabrication of multilayer flat thin films by the Layer-by-Layer (LbL) technique [1,2], During the past few years, many studies have been conducted by applying the LbL technique for the covering of colloidal particles (Fig. 3.1). Subsequent dissolution of the sacrificial core leads to polyelectrolyte microcapsules [3]. 

Hollow polyelectrolyte microcapsules usually exhibit selective permeability the shell is permeable to small molecules such as dyes, but remains impermeable to polymers [24]. However, as in the case of flat films, the polyelectrolyte multilayers can undergo porosity transitions when some parameters that inf luence the degree of association of the polymer chains are varied. The main application of this reversible permeability is the encapsulation of macromolecules and, furthermore, their controlled release. 

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