The present study focused on the more detailed characterization of chitosan-carrageenan-based matrix tablets with respect to their potential utilization for drug targeting in the intestine. The study systematically dealt with the particular stages of the dissolution process, as well as with different views of the physico-chemical processes involved in these stages. The initial swelling of the tablets in the acidic medium based on the combined microscopy-calorimetry point of view, the pH-induced differences in the erosion and swelling of the tested tablets, and the morphological characterization of the tablets are discussed. The dissolution kinetics correlated with the rheological properties and mucoadhesive behavior of the tablets are also reported, and, correspondingly, the formulations with suitable properties were identified. It was confirmed that the formation of the chitosan-carrageenan polyelectrolyte complex may be an elegant and beneficial alternative solution for the drug targeting to the intestine by the matrix tablet.

• Klíčová slova
• carrageenan, chitosan, drug targeting, polyelectrolyte complex,
• Publikační typ
• časopisecké články MeSH

Conductive hydrogels are polymeric materials that are promising for bioelectronic applications. In the present study, a complex based on sulfonic cryogels and poly(3,4-ethylenedioxythiophene) (PEDOT) was investigated as an example of a conductive hydrogel. Preparation of polyacrylate cryogels of various morphologies was carried out by cryotropic gelation of 3-sulfopropyl methacrylate and sulfobetaine methacrylate in the presence of functional comonomers (2-hydroxyethyl methacrylate and vinyl acetate). Polymerization of 3,4-ethylenedioxythiophene in the presence of several of the above cryogels occurred throughout the entire volume of each polyelectrolyte cryogel because of its porous structure. Structural features of cryogel@PEDOT complexes in relation to their electrochemical properties were investigated. It was shown that poly(3,4-ethylenedioxythiophene) of a linear conformation was formed in the presence of a cryogel based on sulfobetaine methacrylate, while minimum values of charge-transfer resistance were observed in those complexes, and electrochemical properties of the complexes did not depend on diffusion processes.

• Klíčová slova
• composite PEDOT@polyelectrolyte, electrochemical impedance spectroscopy, polyelectrolyte gels,
• MeSH
• kryogely * chemie   MeSH
• methakryláty * chemie   MeSH
• polyelektrolyty MeSH
• polymerizace MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 3,4-ethylenedioxythiophene MeSH Prohlížeč
• kryogely * MeSH
• methakryláty * MeSH
• polyelektrolyty MeSH
• sulfobetaine MeSH Prohlížeč

Cryo-electron microscopy (cryo-EM) is one of the primary methods used to determine the structures of macromolecules and their complexes. With the increased availability of cryo-electron microscopes, the preparation of high-quality samples has become a bottleneck in the cryo-EM structure-determination pipeline. Macromolecules can be damaged during the purification or preparation of vitrified samples for cryo-EM, making them prone to binding to the grid support, to aggregation or to the adoption of preferential orientations at the air-water interface. Here, it is shown that coating cryo-EM grids with a negatively charged polyelectrolyte, such as single-stranded DNA, before applying the sample reduces the aggregation of macromolecules and improves their distribution. The single-stranded DNA-coated grids enabled the determination of high-resolution structures from samples that aggregated on conventional grids. The polyelectrolyte coating reduces the diffusion of macromolecules and thus may limit the negative effects of the contact of macromolecules with the grid support and blotting paper, as well as of the shear forces on macromolecules during grid blotting. Coating grids with polyelectrolytes can readily be employed in any laboratory dealing with cryo-EM sample preparation, since it is fast, simple, inexpensive and does not require specialized equipment.

• Klíčová slova
• aggregation, coating cryo-EM grids, cryo-EM, sample preparation, ssDNA,
• MeSH
• elektronová kryomikroskopie MeSH
• jednovláknová DNA * MeSH
• makromolekulární látky MeSH
• odběr biologického vzorku * MeSH
• polyelektrolyty MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• jednovláknová DNA * MeSH
• makromolekulární látky MeSH
• polyelektrolyty MeSH

Whey protein isolate (WPI), employed as a carrier for a wide range of bioactive substances, suffers from a lack of colloidal stability in physiological conditions. Herein, we developed innovative stabilized PolyElectrolyte Nanoparticles (PENs) obtained by two techniques: polyelectrolyte complexation of negatively charged WPI and positively charged chitosan (CS), and ionic gelation in the presence of polyanion tripolyphosphate (TPP). Therefore, the WPI-based core was coated with a CS-based shell and then stabilized by TPP at pH 8. The nanostructures were characterized by physiochemical methods, and their encapsulation efficiency and in vitro release were evaluated. The spherical NPs with an average size of 248.57 ± 5.00 nm and surface charge of +10.80 ± 0.43 mV demonstrated high encapsulation efficiency (92.79 ± 0.69) and sustained release of a positively charged chemotherapeutic agent such as doxorubicin (DOX). Z-average size and size distribution also presented negligible increases in size and aggregates during the three weeks. The results obtained confirm the effectiveness of the simultaneous application of these methods to improve the colloidal stability of PEN.

• Klíčová slova
• TPP, WPI, chitosan, colloidal stability,
• MeSH
• chitosan * chemie   MeSH
• lékové transportní systémy MeSH
• nanočástice * chemie   MeSH
• nosiče léků chemie   MeSH
• polyelektrolyty chemie   MeSH
• syrovátkové proteiny MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chitosan * MeSH
• nosiče léků MeSH
• polyelektrolyty MeSH
• syrovátkové proteiny MeSH

The formation and properties of supported lipid bilayers (SLB) containing hydrophobic nanoparticles (NP) was studied in relation to underlying cushion obtained from selected polyelectrolyte multilayers. Lipid vesicles were formed from zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) in phosphate buffer (PBS). As hydrophobic nanoparticles - quantum dots (QD) with size of 3.8nm (emission wavelength of 420nm) were used. Polyelectrolyte multilayers (PEM) were constructed by the sequential, i.e., layer-by-layer (LbL) adsorption of alternately charged polyelectrolytes from their solutions. Liposomes and Liposome-QDs complexes were studied with Transmission Cryo-Electron Microscopy (Cryo-TEM) to verify the quality of vesicles and the position of QD within lipid bilayer. Deposition of liposomes and liposomes with quantum dots on polyelectrolyte films was studied in situ using quartz crystal microbalance with dissipation (QCM-D) technique. The fluorescence emission spectra were analyzed for both: suspension of liposomes with nanoparticles and for supported lipid bilayers containing QD on PEM. It was demonstrated that quantum dots are located in the hydrophobic part of lipid bilayer. Moreover, we proved that such QD-modified liposomes formed supported lipid bilayers and their final structure depended on the type of underlying cushion.

• Klíčová slova
• Cryo-TEM, Quantum dots, Quantum dots-liposome complex, Supported lipid bilayer, Theranostic nanocontainers,
• MeSH
• elektronová kryomikroskopie MeSH
• fosfatidylcholiny chemie   MeSH
• fosfatidylethanolaminy chemie   MeSH
• fosforylcholin chemie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• kvantové tečky * MeSH
• lipidové dvojvrstvy chemie   MeSH
• polyelektrolyty chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine MeSH Prohlížeč
• 1-palmitoyl-2-oleoylphosphatidylcholine MeSH Prohlížeč
• fosfatidylcholiny MeSH
• fosfatidylethanolaminy MeSH
• fosforylcholin MeSH
• lipidové dvojvrstvy MeSH
• polyelektrolyty MeSH

The effect of polyelectrolyte chain length on the formation of multilayered assemblies of alternating globular proteins and linear polyanions prepared by the layer-by-layer electrostatic adsorption technique was investigated. The systems studied were albumin/sodium poly(styrenesulfonate), immunoglobulin G/sodium poly(styrenesulfonate), albumin/sodium dextran sulfate, and albumin/heparin. The formation of assemblies was followed using FTIR multiple internal reflection spectroscopy. While the amount of polyelectrolyte adsorbed on the first (primary) protein layer did not depend on its molecular weight, the effect of polyelectrolyte chain length was clearly observed in the following steps of alternating adsorption. Some short-chain polyanion molecules were removed from the surface when a next protein layer was adsorbed from solution. The short polyanion chains were not able to make a sufficient number of ion pairs for stable interaction with additional protein molecules and left the surface as soluble protein/polyanion complexes. The most pronounced effect could be seen with sodium poly(styrenesulfonate) of Mw up to ca. 2 x 10(4), but a detectable effect could be traced even up to Mw ca. 8 x 10(4). Such a pronounced effect, however, was not observed with dextran sulfate. The effect of molecular weight of heparin was clearly observed but all heparins tested, regardless of their molecular weight, effectively assembled with albumin to form multilayer.

• MeSH
• adsorpce MeSH
• albuminy chemie   MeSH
• časové faktory MeSH
• elektrolyty * chemie   MeSH
• heparin chemie   MeSH
• imunoglobulin G chemie   MeSH
• imunoglobuliny chemie   MeSH
• ionty MeSH
• koncentrace vodíkových iontů MeSH
• lidé MeSH
• polyelektrolyty MeSH
• polymery MeSH
• polystyreny chemie   MeSH
• prasata MeSH
• síran dextranu chemie   MeSH
• skot MeSH
• soli chemie   MeSH
• spektroskopie infračervená s Fourierovou transformací metody   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• albuminy MeSH
• elektrolyty * MeSH
• heparin MeSH
• imunoglobulin G MeSH
• imunoglobuliny MeSH
• ionty MeSH
• polyanions MeSH Prohlížeč
• polyelektrolyty MeSH
• polymery MeSH
• polystyrene sulfonic acid MeSH Prohlížeč
• polystyreny MeSH
• síran dextranu MeSH
• soli MeSH

Polyplexes are polyelectrolyte complexes of DNA and polycations, designed for potential gene delivery. We investigated the properties of new polyplexes formed from cholesterol-modified polycations and DNA. Three complexes were tested; their cholesterol contents were 1.4, 6.3, and 8.7 mol %. UV spectroscopy and fluorescence assay using ethidium bromide proved the formation of polyplexes. The kinetics of turbidity of polyplexes solutions in physiological solution showed that the colloid stability of polyplexes increases with increasing content of cholesterol in polycations. Dynamic, static, and electrophoretic light scattering, small-angle X-ray scattering, and atomic force microscopy were used for characterization of polyplexes. The observed hydrodynamic radii of polyplexes were in the range of 30-60 nm; they were related to the polycation/DNA ratio and hydrophobicity of the used polycations (the cholesterol content). The properties of polyplex particles depend, in addition to polycation structure, on the rate of polycation addition to DNA solutions.

• MeSH
• DNA chemie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• kinetika MeSH
• magnetická rezonanční spektroskopie MeSH
• mikroskopie atomárních sil MeSH
• molekulární struktura MeSH
• polyaminy chemie   MeSH
• polyelektrolyty MeSH
• radiační rozptyl MeSH
• spektrofotometrie ultrafialová MeSH
• teoretické modely MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• polyaminy MeSH
• polycations MeSH Prohlížeč
• polyelektrolyty MeSH

A novel polyelectrolyte nanocarrier was synthesized via layer-by-layer self-assembly of polycationic and polyanionic chains. The nanocarrier is composed of polyglutamate grafted chitosan core, dextran sulfate as a complexing agent, and polyethyleneimine shell decorated with folic acid. This polyelectrolyte complex has unique physicochemical properties so that the core is considered as an efficient carrier for LTX-315 and melittin peptides, and the shell is suitable for delivery of miR-34a. The spherical nanocarriers with an average size of 123 ± 5 nm and a zeta potential of -36 ± 1 mV demonstrated controlled-release of gene and peptides ensured a synergistic effect in establishing multiple cell death pathways on chemoresistance human breast adenocarcinoma cell line, MDA-MB-231. In vitro cell viability assays also revealed no cytotoxicity for the nanocarriers, and an IC50 of 15 μg/mL and 150 μg/mL for melittin and LTX-315, respectively, after 48 h, whereas co-delivery of melittin with miR-34a increased smart death induction by 54%.

• Klíčová slova
• Active targeting, Gene-peptide co-delivery, LTX-315, Melittin, Polyelectrolyte nanocarrier, Polyglutamate grafted chitosan, miR-34a,
• MeSH
• buněčná smrt MeSH
• chitosan * MeSH
• lidé MeSH
• melitten farmakologie   MeSH
• mikro RNA aplikace a dávkování   genetika   MeSH
• nádorové buněčné linie MeSH
• nádory prsu * farmakoterapie   MeSH
• nanočástice * MeSH
• oligopeptidy MeSH
• polyelektrolyty MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chitosan * MeSH
• LTX-315 MeSH Prohlížeč
• melitten MeSH
• mikro RNA MeSH
• MIRN34 microRNA, human MeSH Prohlížeč
• oligopeptidy MeSH
• polyelektrolyty MeSH

Polysaccharides like hyaluronan (HA) and chondroitin sulfate (CS) are native of the brain's extracellular matrix crucial for myelination and brain maturation. Despite extensive research on HA and CS as drug delivery systems (DDS), their high water solubility limits their application as drug carriers. This study introduces an injectable DDS using aldehyde-modified hyaluronic acid (HAOX) hydrogel containing polyelectrolyte complexes (PEC) formed with calcium, gelatin, and either CS or aldehyde-modified CS (CSOX) to deliver minocycline for Multiple Sclerosis therapy. PECs with CSOX enable covalent crosslinking to HAOX, creating immobilized PECs (HAOX_PECOX), while those with CS remain unbound (HAOX_PECS). The in situ forming DDS can be administered via a 20 G needle, with rapid gelation preventing premature leakage. The system integrates into an implanted device for minocycline release through either Fickian or anomalous diffusion, depending on PEC immobilization. HAOX_PECOX reduced burst release by 88 %, with a duration of 127 h for 50 % release. The DDS exhibited an elastic modulus of 3800 Pa and a low swelling ratio (0-1 %), enabling precise control of minocycline release kinetics. Released minocycline reduced IL-6 secretion in the Whole Blood Monocytes Activation Test, suggesting that DDS formation may not alter the biological activity of the loaded drug.

• Klíčová slova
• Chondroitin sulphate, Hyaluronic acid, Hydrogel, Minocycline, Polyelectrolyte complexes,
• MeSH
• aldehydy chemie   MeSH
• chondroitinsulfáty * chemie   MeSH
• hydrogely * chemie   farmakologie   MeSH
• interleukin-6 metabolismus   MeSH
• kyselina hyaluronová * chemie   MeSH
• lékové transportní systémy metody   MeSH
• lidé MeSH
• minocyklin * chemie   farmakologie   aplikace a dávkování   MeSH
• nosiče léků * chemie   MeSH
• polyelektrolyty * chemie   MeSH
• uvolňování léčiv MeSH
• želatina * chemie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aldehydy MeSH
• chondroitinsulfáty * MeSH
• hydrogely * MeSH
• interleukin-6 MeSH
• kyselina hyaluronová * MeSH
• minocyklin * MeSH
• nosiče léků * MeSH
• polyelektrolyty * MeSH
• želatina * MeSH

Mixing of oppositely charged polyelectrolytes can result in phase separation into a polymer-poor supernatant and a polymer-rich polyelectrolyte complex (PEC). We present a new coarse-grained model for the Grand-reaction method that enables us to determine the composition of the coexisting phases in a broad range of pH and salt concentrations. We validate the model by comparing it to recent simulations and experimental studies, as well as our own experiments on poly(acrylic acid)/poly(allylamine hydrochloride) complexes. The simulations using our model predict that monovalent ions partition approximately equally between both phases, whereas divalent ones accumulate in the PEC phase. On a semiquantitative level, these results agree with our own experiments, as well as with other experiments and simulations in the literature. In the sequel, we use the model to study the partitioning of a weak diprotic acid at various pH values of the supernatant. Our results show that the ionization of the acid is enhanced in the PEC phase, resulting in its preferential accumulation in this phase, which monotonically increases with the pH. Currently, this effect is still waiting to be confirmed experimentally. We explore how the model parameters (particle size, charge density, permittivity, and solvent quality) affect the measured partition coefficients, showing that fine-tuning of these parameters can make the agreement with the experiments almost quantitative. Nevertheless, our results show that charge regulation in multivalent solutes can potentially be exploited in engineering the partitioning of charged molecules in PEC-based systems at various pH values.

• Publikační typ
• časopisecké články MeSH