[The use of a urethral catheter with an ultrasound-induced biopolymer drug coating for the prevention of recurrent bladder neck sclerosis in patients after endoscopic treatment of benign prostate hyperplasia].

Recurrent bladder neck sclerosis is one of the common complications of endoscopic treatment of benign prostate hyperplasia, which often leads to multiple re-operations, including complex open and laparoscopic reconstructive procedures. One of the most promising minimally invasive methods for preventing recurrence of bladder neck sclerosis is balloon dilatation under transrectal ultrasound guidance. To improve the results of using this technique, a urethral catheter with a biopolymer coating, capable of depositing a drug and eluting it under the influence of diagnostic ultrasound, was proposed.

Fluorescent polymer markers photoconvertible with a 532 nm laser for individual cell labeling.

Fluorescent photoconvertible materials and molecules have been successfully exploited as bioimaging markers and cell trackers. Recently, the novel fluorescent photoconvertible polymer markers have been developed that allow the long-term tracking of individual labeled cells. However, it is still necessary to study the functionality of this type of fluorescent labels for various operating conditions, in particular for commonly used discrete wavelength lasers. In this article, the photoconversion of fluorescent polymer labels with both pulsed and continuous-wave lasers with 532 nm-irradiation wavelength, and under different laser power densities were studied. The photoconversion process was described and its possible mechanism was proposed. The peculiarities of fluorescent polymer capsules performance as an aqueous suspension and as a single capsule were described. We performed the successful nondestructivity marker photoconversion inside RAW 264.7 monocyte/macrophage cells under continuous-wave laser with 532 nm-irradiation wavelength, showing prospects of these fluorescent markers for long-term live cell labeling.

Human Mesenchymal Stem Cells as a Carrier for a Cell-Mediated Drug Delivery.

A number of preclinical and clinical studies have demonstrated the efficiency of mesenchymal stromal cells to serve as an excellent base for a cell-mediated drug delivery system. Cell-based targeted drug delivery has received much attention as a system to facilitate the uptake a nd transfer of active substances to specific organs and tissues with high efficiency. Human mesenchymal stem cells (MSCs) are attracting increased interest as a promising tool for cell-based therapy due to their high proliferative capacity, multi-potency, and anti-inflammatory and immunomodulatory properties. In particular, these cells are potentially suitable for use as encapsulated drug transporters to sites of inflammation. Here, we studied the in vitro effects of incorporating synthetic polymer microcapsules at various microcapsule-to-cell ratios on the morphology, ultrastructure, cytokine profile, and migration ability of human adipose-derived MSCs at various time points post-phagocytosis. The data show that under appropriate conditions, human MSCs can be efficiently loaded with synthesized microcapsules without damaging the cell's structural integrity with unexpressed cytokine secretion, retained motility, and ability to migrate through 8 µm pores. Thus, the strategy of using human MSCs as a delivery vehicle for transferring microcapsules, containing bioactive material, across the tissue-blood or tumor-blood barriers to facilitate the treatment of stroke, cancer, or inflammatory diseases may open a new therapeutic perspective.

Photodynamic therapy platform based on localized delivery of photosensitizer by vaterite submicron particles.

The elaboration of biocompatible and biodegradable carriers for photosensitizer targeted delivery is one of the most promising approaches in a modern photodynamic therapy (PDT). This approach is aimed at reducing sides effects connected with incidental toxicity in healthy tissue whilst also enhancing drug accumulation in the tumour area. In the present work, Photosens-loaded calcium carbonate (CaCO3) submicron particles in vaterite modification are proposed as a novel platform for anticancer PDT. Fast penetration of the carriers (0.9±0.2µm in diameter) containing 0.12% (w/w) of the photosensitizer into NIH3T3/EGFP cells is demonstrated. The captured particles provide the dye localization inside the cell increasing its local concentration, compared with "free" Photosens solution which is uniformly distributed throughout the cell. The effect of photosensitizer encapsulation into vaterite submicron particles on cell viability under laser irradiation (670nm, 19mW/cm(2), 10min) is discussed in the work. As determined by a viability assay, the encapsulation renders Photosens more phototoxic. By this means, CaCO3 carriers allow improvement of the photosensitizer effectiveness supposing, therefore, the reduction of therapeutic dose. Summation of these effects with the simplicity, upscalability and cheapness of fabrication, biocompatibility and high payload ability of the vaterite particles hold out the prospect of a novel PDT platform.

Impact of high-frequency ultrasound on nanocomposite microcapsules: in silico and in situ visualization.

The impact of high-frequency (1.2 MHz) ultrasound with a power density of 0.33 W cm(-2) on microcapsule nanocomposite shells with embedded zinc oxide nanoparticles was investigated by exploring modeling simulations and direct visualization. For the first time the sonication effect has been monitored in situ on individual microcapsules upon exposure of their aqueous suspension to ultrasound. The stress distribution on the microcapsule shell for the impact of ultrasound with high (1.2 MHz) and low (20 kHz) frequency at two fixed intensities (0.33 and 30 W cm(-2)) has been modeled. As shown in silico and experimentally the nanocomposite microcapsules were destroyed more effectively by the action of high-frequency (1.2 MHz) ultrasound in comparison to the low frequency (20 kHz) one with the same power density.

Biodegradable fibre scaffolds incorporating water-soluble drugs and proteins.

A new type of biodegradable drug-loaded fibre scaffold has been successfully produced for the benefit of water-soluble drugs and proteins. Model drug loaded calcium carbonate (CaCO3) microparticles incorporated into poly(lactic acid-co-glycolic acid) (PLGA) fibres were manufactured by co-precipitation of CaCO3 and the drug molecules, followed by electrospinning of a suspension of such drug-loaded microparticles in a PLGA solution. Rhodamine 6G and bovine serum albumin were used as model drugs for our release study, representing small bioactive molecules and protein, respectively. A bead and string structure of fibres was achieved. The drug release was investigated with different drug loadings and in different pH release mediums. Results showed that a slow and sustained drug release was achieved in 40 days and the CaCO3 microparticles used as the second barrier restrained the initial burst release.

[Biodegradable microcapsules containing DNA for the new DNA vaccine design].

A general method for the preparation of biodegradable microcapsules capable of antigen inclusion is suggested. Multilayer microcapsules were obtained by the method of level-by-level sorption of various polyelectrolytes (alginate, poly-L-lysine, kappa-carrageenan, and chitosan and dextran derivatives). High inclusion efficiency was found for protein and plasmid DNA (no less than 90%). A series of microcapsules with included pTKShi plasmid that incorporated a genome site encoding the E(2) polypeptide of the classic pig plague virus were obtained for carrying out in vivo experiments. It was shown that introduction to mice of microcapsules with the included pTKShi plasmid induced an immune response. The highest antibody titers of the mouse blood sera were obtained in immunization by microcapsules based on the modified dextran/carrageenan and modified chitosan/carrageenan. The method of antigen inclusion into biodegradable microcapsules could be used for the development of encapsulated vaccines of a new generation (DNA vaccines).

Photoactivated release of cargo from the cavity of polyelectrolyte capsules to the cytosol of cells.

Polyelectrolyte capsules with metal nanoparticles in their walls and fluorescently labeled polymers as cargo inside their cavity were prepared. Capsules were ingested by living cells with no uncontrolled release of the cargo upon the incorporation process. Photoinduced heating of the metal nanoparticles in the capsule walls lead to rupture of the capsule walls, and the polymeric cargo was released to the whole cytosol. Viability tests demonstrate that opening of capsules at moderate light intensities does not impair the cellular metabolism, whereas capsule opening at high light intensities ultimately leads to cell death.

[Polyelectrolyte microcapsules as systems for delivery of biologically active substances].

Novel biodegradable microcapsules for delivery of biologically active substances (BAS) were prepared by layer-by-layer (LbL) adsorption of oppositely charged polyelectrolytes, namely sodium alginate (Alg) and poly-L-lysine (PLL). To immobilize these BAS, porous spherical CaCO3 microparticles were used as templates. The templates (cores) were coated with several layers of oppositely charged polyelectrolytes forming shell on a core surface. The core-shell microparticles were converted into hollow microcapsules by a core dissolution after an EDTA treatment. Mild conditions for microcapsule fabrication allow to perform an entrapment of various biomolecules while keeping their bioactivity. Biocompatibility and biodegradable capability of the polyelectrolytes give a possibility to use the microcapsules as the target delivery systems. Chymotrypsin (Chym) entrapped into the microcapsules was used as a model enzyme. The immobilized enzyme was found to keep about 86% of the activity compared to a native Chym. The obtained microcapsules were stable at an acidic medium while they could be easily decomposed by trypsin treatment at an slightly alkaline medium. Chym was shown to be active after being released from the microcapsules decomposed by trypsin treatment. Thus, the microcapsules prepared by the LbL - technique can be used for the development of new type of BAS delivery systems in humans and animals.

Polyelectrolyte/magnetite nanoparticle multilayers: preparation and structure characterization.

Polyelectrolyte composite planar films containing a different number of iron oxide (Fe3O4) nanoparticle layers have been prepared using the layer-by-layer adsorption technique. The nanocomposite assemblies were characterized by ellipsometry, UV-vis spectroscopy, and AFM. Linear growth of the multilayer thickness with the increase of the layer number, N, up to 12 reflects an extensive character of this parameter in this range. A more complicated behavior of the refractive index is caused by changes in the multilayer structure, especially for the thicker nanocomposites. A quantitative analysis of the nanocomposite structure is provided comparing a classical and a modified effective medium approach taking into account the influence of light absorption by the Fe3O4 nanoparticles on the complex refractive index of the nanocomposite and contributions of all components to film thickness. Dominant influence of co-adsorbed water on their properties was found to be another interesting peculiarity of the nanocomposite film. This effect, as well as possible film property modulation by light, is discussed.

Novel type of self-assembled polyamide and polyimide nanoengineered shells--fabrication of microcontainers with shielding properties.

Two types of microcontainers were prepared by using the adsorption of polyamide on the surface of micrometer-sized inorganic porous calcium carbonate microparticles followed by thermal conversion of the polyamide layers into polyimide coatings. The effect of the preparation conditions on the structure and morphology of the microcontainers was studied by transmission electron microscopy and scanning electron microscopy. The smoothest and defect-free coatings were prepared using polyethylenimine as the supporting polymer. The thickness of the polyamide/polyimide shells was estimated by atomic force microscopy and scanning electron microscopy between 50 and 150 nm depending on the quantity of the layers. The water-soluble antibiotic, doxorubicin hydrochloride, was used as a model compound to demonstrate the efficiency of the microcontainers for encapsulation. The resistance of the novel microcontainers to solvent treatment was visualized by the confocal scanning fluorescence microscopy. It was demonstrated that the combination of the high thermal and chemical resistance of polyamide/polyimide shell and the sorption capacity of the CaCO3 is very useful for development of highly protective microcontainers and thermal detectors for smart fabrics.

[Entrapment of herbal extracts in biodegradable microcapsules].

The microcapsules with entrapped herbal water-soluble extracts Plantago major and Calendula officinalis L. (HE) were prepared by LbL-adsorption of carrageenan and modificated chitosan onto CaCO3 microparticles with their subsequent dissolving after the treatment of EDTA. Entrapment of HE was performed by adsorption and co-precipitation techniques. The co-precipitation provided better entrapment of HE compared to adsorption. In vitro release kinetics in an artificial gastric juice (AGJ) was studied. The HE release was shown to accelerate gastric ulcer treatment in a rat model.

Layer-by-layer coating of degradable microgels for pulsed drug delivery.

Recently, we reported on "self-rupturing" microcapsules which consist of a biodegradable dextran-based microgel surrounded by a polyelectrolyte membrane. Degradation of the microgel increases the swelling pressure in the microcapsules which, when sufficiently high, ruptures the surrounding polyelectrolyte membrane. The membrane surrounding the microgels is deposited using the layer-by-layer (LbL) technique, which is based on the alternate adsorption of oppositely charged polyelectrolytes onto a charged substrate. In this paper, we characterize with confocal microscopy, electrophoretic mobility, scanning electron microscopy and atomic force microscopy in detail the deposition and the properties of the LbL coatings on the dextran microgels. We show that by fine-tuning the properties of both the microgel core and the LbL membrane the swelling pressure which is evoked by the degradation of the microgel is indeed able to rupture the surrounding LbL membrane. Further, we show that the application of an LbL coating on the surface of the microgels dramatically lowers the burst release from the microcapsules and results in massive release at the time the microcapsules rupture.

Cytotoxicity of nanoparticle-loaded polymer capsules.

Cytotoxic effects of micrometer-sized polymer capsules composed out of alternating layers of polystyrenesulfonate (PSS) and polyallylamine hydrochloride (PAH) on a fibroblast cell line have been investigated with an adhesion assay. For the purpose of visualization with fluorescence nanometer-sized CdTe nanoparticles have been embedded in the walls of the capsules. Similar to free CdTe nanoparticles, toxic Cd-ions are also released from CdTe nanoparticles that have been embedded in capsules. At high capsule concentrations, the capsules start to sediment on top of the cells and thus impair cell viability.

Inclusion of proteins into polyelectrolyte microparticles by alternative adsorption of polyelectrolytes on protein aggregates.

A new method of protein immobilization into polyelectrolyte microparticles by alternative adsorption of the oppositely charged polyelectrolytes on the aggregates obtained by salting out of protein is proposed. The model protein alpha-chymotrypsin (ChT) was included in the polyelectrolyte microparticles obtained by various number of polyelectrolyte adsorption steps (from 1 to 11). The main parameters of ChT inclusion into microparticles were calculated. Scanning electron and optical microscopy were used for characterization of morphology and determination of particle size which was from 1 to 10 micro m in most cases. It was shown that the size and shape of protein-containing particles and protein aggregates used as a matrix were similar. Change in ChT enzymatic activity during entrapment into polyelectrolyte particles and activity of released protein were studied. The effect of pH on release of incorporated proteins was investigated; it was shown that change in pH and the number of polyelectrolyte adsorption steps allows protein release to be manipulated.

Artificial cell based on lipid hollow polyelectrolyte microcapsules: channel reconstruction and membrane potential measurement.

A new model system as an artificial cell based on hollow polyelectrolyte microcapsules (HPM), fabricated by step-wise adsorption of polyelectrolytes and phospholipids, was proposed. To demonstrate the feasibility of the functioning of HPM coated with lipid layers as a model biosystem, the membrane permeability for ions and the channel reconstruction were examined by measuring the membrane potential as one of the most important cell parameters. The membrane potential was measured by confocal microscopy using the potentiometric fluorescent dye tetramethylrhodamine ethyl ester perchlorate (TMRE). The influence of the lipid composition (phosphatidylcholine--DPPC-HPM, phosphatidylcholine/phosphatidic acid 9/1-(DPPC/DPPA)-HPM) and metal cations (Na+, K+, Ca2+) on the membrane potential was shown. Addition of DPPA was found to lead to an increase of the negative membrane potential value. To investigate the ion-transport activity of the lipid-HPM, the ion channel-forming peptides valinomycin and gramicidin were used. The selectivity of the valinomycin and gramicidin channels for K+ and for K+, and Na+ ions, respectively, and the tolerance for Ca2+ ions is evidence that lipid-HPM functions as an artificial cell.

Encapsulation of proteins by layer-by-layer adsorption of polyelectrolytes onto protein aggregates: factors regulating the protein release.

A novel method of protein encapsulation is proposed. Preformed protein aggregates are covered with polyelectrolyte layers by means of layer-by-layer adsorption. The polyelectrolyte membrane prevents protein leakage out of the capsule. Using chymotrypsin as a model enzyme the capsule wall selective permeability was demonstrated for substrates and inhibitors of different molecular weight and solubility.

Microencapsulation by means of step-wise adsorption of polyelectrolytes.

Step-wise adsorption of polyelectrolytes is used for the fabrication of micro- and nanocapsules with determined size, capsule wall composition and thickness. The capsule walls made of polyelectrolyte multilayers exclude high molecular weight compounds. Assembling of lipid layers onto these polyelectrolyte capsules prevents the permeation of small dyes. Encapsulation of magnetite nanoparticles is demonstrated and the features of these novel capsules are discussed.

[Conformation and molecular and ionic transformations of polycytidylic acid immobilized in multilayer Langmuir and polyelectrolyte films]. / Konformatsionnoe sostoianie i osobennosti molekuliarno-ionnogo prevrashcheniia politsitidilovoi kisloty, immobilizovannoi v mul'tisloinykh lengmiurovskikh i poliélektrolitnoi plenkakh.

Multilayer films of complexes of polycytidylic acid with dioctadecyldimetylammonium were obtained by the Langmuir-Blodgett method (LB films), and complexes of poly(C) with polycations (poly-L-lysisne, polyethyleneimine, polyallylamine) were obtained by the method of alternate adsorption (polyionic assembly) from solutions of oppositely charged polyelectrolytes on the solid carrier (SA films). It was shown that poly(C) exists in SA films in a single-stranded state irrespective of whether in the starting solution it occurred in the single-stranded nonprotonated or double-stranded protonated conformation. Conversely, in the LB film poly(C) preferred to be in a double protonated conformation. UV-spectra of water-insoluble LB and SA films at different pH values of surrounding water medium were investigated. Proton titration curves of poly(C) immobilized in LB films were obtained. The analysis of the shape of titration curves showed that the molecular-ionic transformation of poly(C) in LB films is accompanied by both the conformational transition of the polynucleotide and the molecular rearrangement in the whole film. Poly(C) was found to transform from the double- to single-stranded state and vice versa in the "deprotonation-protonation" cycle of LB film due to cooperative release/binding of hydrogen ions by cytosine bases. In contrast, poly(C) "protonation-deprotonation" in SA films occurred without conformational transitions of the polynucleotide. As opposed to poly(C) in solution a rather big hysteresis of forward and back titration curves was found for both types of multilayer films, indicating molecular rearrangements in films. The reason for the structural transformations of poly(C) upon fabrication of LB or SA films and the mechanism of molecular ionic transformations of poly(C) in films are discussed in terms of a simple model of ion exchange. An assumption about the nature of structural transformations of LB and SA films during their protonation-deprotonation is put forward.