Biomedical subjects

Gleb B Sukhorukov

Publications and source records attributed to Gleb B Sukhorukov.

4 recordsLinked to original sources

PubMed2002

Hollow polymer shells from biological templates: fabrication and potential applications.

Three-dimensional ultrathin polymer shells have been produced by a combination of step-by-step adsorption of polyelectrolytes on glutaraldehyde-treated human erythrocytes and subsequent solubilization of the cytoplasmatic constituents by means of a deproteinizing agent. The obtained hollow films preserve both the size and shape of the templating cells. This opens a pathway for the fabrication of polymeric capsules within a wide range of size and shape by using various biological templates. They may have exciting potential applications, such as templates for nanocomposites, as containers for a large class of materials, or as cages for chemical reactions. The thickness of the films can be adjusted over a large range: from a few nm up to several tens of nm. The polymer shells are permeable to small molecules and ions but not to macromolecules. An increase in the ionic strength of the solution up to 100 mmol make the capsules permeable for proteins. Permeability and conductivity studies have provided evidence that the adsorption of lipids on polyelectrolyte layers is a means of producing capsules with controlled permeability properties. 6-Carboxyfluorescein and Rhodamin 6G were precipitated within the capsules.

Biotechnology↗

PubMed2002

Multilayer alginate/protamine microsized capsules: encapsulation of alpha-chymotrypsin and controlled release study.

Stable polyelectrolyte microcapsules with size 6.5 microm were produced by means of the layer-by-layer adsorption of sodium alginate and protamine to surface of melamine formaldehyde microparticles. Core decomposition at low pH leads to formation of polyelectrolyte multilayered capsules filled with alginate gel. A proteolytic enzyme, alpha-chymotrypsin, was loaded into these microcapsules by embedding in alginate gel with high efficacy. The protein in the capsules was found to retain a high physiological activity of about 70% showed with fluorescent product. The protein was found to keep inside the microcapsules in water and acid (HCl solution, pH 1.7) during 24 and 4 h, respectively, while 75-85% of protein can be revealed in supernatant after 6 h incubation at pH 8.0 (0.05 M Tris buffer) in the presence of 2.5% w/v of sodium deoxycholate. The release rate of enzyme from multilayer alginate/protamine microcapsules can be regulated by additional adsorption of polyelectrolytes onto the microcapsules with encapsulated protein. Such protein-loaded capsules can be proposed as a drug delivery system with controllable release properties.

Alginates↗

PubMedDate not supplied

Layer-by-layer engineering of biocompatible, decomposable core-shell structures.

The objective of the present investigation was to fabricate composite colloidal particles consisting of a sacrificial, decomposable template of biodegradable nature covered with biocompatible polyelectrolyte multilayers using the layer-by-layer sequential adsorption technique. Poly-dl-lactic acid and poly(dl-lactic-co-glycolic acid) were chosen to design the microparticulate template, and a preliminary feasibility study was carried out with poly(styrene sulfonate sodium)-poly(allylamine hydrochloride) as shell components. The properties of both core-shell and hollow structures obtained by core dissolution were characterized by confocal laser scanning microscopy, microelectrophoresis, scanning force microscopy, and scanning electron microscopy. The concept was then extended to biocompatible polyelectrolytes as shell wall building blocks to deduce stable hollow capsules with tailored properties. Uniform, complete coating with oppositely charged polyelectrolyte pairs was achieved for all the combinations investigated. The results demonstrate that polyester microparticles could serve as viable alternative components to conventionally employed templates to derive hollow capsules with defined size, shape, and shell thickness. With all the components used for fabrication being biocompatible, these polyelectrolyte capsules may find interesting applications in the fields of biology, biochemistry, biotechnology, and drug delivery.

Biocompatible Materials↗

PubMedDate not supplied

Loading the multilayer dextran sulfate/protamine microsized capsules with peroxidase.

Stable polyelectrolyte capsules were produced by the layer-by-layer (LbL) assembling of biodegradable polyelectrolytes, dextran sulfate and protamine, on melamine formaldehyde (MF) microcores followed by the cores decomposition at low pH. The mean diameter of the capsules at pH 3-5 was 8.0 +/- 0.2 microm, which is more than that diameter of the templates (5.12 +/- 0.15 microm). With pH growing up to 7-8, the capsules enlarged, swelling up to the diameter 9-10 microm. The microcapsules were loaded with horseradish peroxidase. Seemingly, peroxidase is embedded in the gellike structure in the microcapsule interior formed by MF residues in the complex with polymers used for LbL coating as proved by Raman confocal spectroscopy. The amount of finally incorporated peroxidase increased from 0.2 x 10(8) to 2.2 x 10(8) peroxidase molecules per capsule with pH growing from 5 to 8. The pH shifts causing changes in capsule swelling and the replacement of solutions without pH shifts lead to the protein loss. The encapsulated peroxidase showed a high activity (57%), which remained stable for 12 months.

Biocompatible Materials↗