The layer-by-layer (LbL) assembly of polyelectrolyte multilayer films offers a versatile approach to construct ultrathin films with controlled nanostructures and functionalities. The properties of LbL assemblies are strongly influenced by the intrinsic properties of the polyelectrolytes and the assembly conditions. In this study, we investigated the effect of charge content, concentration, deposition time, and molecular weight of polyelectrolytes on the formation and stability of LbL films composed of quaternized dextran (QDex) with varying degrees of substitution (DS) (30%-90%) and heparin (Hep). Surface plasmon resonance analysis revealed that the introduction of a QDex/tannic acid anchoring bilayer effectively reduced the desorption occurring during the deposition of both strong polyelectrolytes, resulting in continuous, exponential growth of QDex/Hep LbL films. The mass deposition increased with increasing DS of QDex, particularly when the QDex concentration and deposition time were optimized. The quartz crystal microbalance with dissipation (QCM-D) monitoring revealed that increasing DS of QDex led to LbL films with progressively higher apparent elastic modulus and viscosity, indicating a transition from soft, water-rich networks to more rigid, cohesive, and less dissipative structures due to enhanced electrostatic interactions (proved by isothermal titration calorimetry) and reduced chain mobility. Furthermore, spectroscopic ellipsometry analysis of 20-bilayer QDex/Hep assemblies deposited on real silica substrates confirmed the increase in film thickness with increasing DS of QDex, especially after the formation of nine QDex/Hep bilayers, where the film structure became more stable. The obtained findings provide detailed insights into the precise control of film growth and stability, which are essential for potential applications in tissue engineering and biomaterial field.

• Klíčová slova
• Charge content, Heparin, Layer-by-layer films, Molecular weight, Polyelectrolytes, QCM-D, Quaternized dextran,
• Publikační typ
• časopisecké články MeSH

Poly(1,2,3-triazole)-based polymers remain underexplored as a versatile platform for biomedical soft materials. Here, we report the modular synthesis of amphiphilic poly(1,2,3-triazole)-co-polytriazolium copolymers (qH-PETH) via copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) polyaddition and post-polymerization quaternization with a degree of quaternization equal to (0.85). These polymers exhibit unusual visible colouration in the absence of chromophores-appearing almost colourless in N-methyl-2-pyrrolidone (NMP), orange in DMSO, and pale orange in water-accompanied by a pronounced red shift in non-polar solvents such as dichloromethane (DCM) or chloroform. This optical behaviour is attributed to solvent-dependent supramolecular aggregation. Dynamic light scattering (DLS) measurements reveal hydrodynamic diameters of <20 nm in water and approximately 500 nm in chloroform for quaternized polymers (qH-PETH), indicating strong aggregation in low-polarity environments. UV-vis spectroscopy and atomic force microscopy (AFM) further support aggregation-induced optical effects modulated by solvent polarity and hydrogen-bonding capacity. Both neutral and quaternized polymers display excellent cytocompatibility toward human cell lines (HeLa, HEK293, THP-1) at concentrations up to 100 μg mL-1, with no detectable immunogenic activation. These findings position poly(1,2,3-triazole)-co-polytriazolium copolymers as a promising, tunable class of biocompatible soft materials for biointerface engineering and responsive biomedical applications.

• Publikační typ
• časopisecké články MeSH

Novel ionene-type cationic copolyimides based on 4,4'-oxydiphthalic anhydride (ODPA), 4,4'-(1,4-phenylenediisopropylidene)bisaniline (BIS P), and 2,6-diaminopyridine (DAP) were synthesized. The copolyimides were obtained in two stages: first, the copolyimides with the 0/1, 0.2/0.8, 0.3/0.7, 0.5/0.5, 0.6/0.4 and 1/0 DAP/Bis P ratios were obtained through thermal imidization, and then quaternization of soluble copolyimides with methyl iodide was conducted for 24 or 48 h. The samples were characterized via FTIR, NMR and EDX methods to confirm their structure and composition. The cationic copolyimides with a DAP content of less than 0.3 showed initial weight loss (onset) at about 250 °C, according to TGA results and demonstrated solubility in chloroform. The highest ionic conductivity value of 0.234 S cm-1 was showed by the sample with 0.3 DAP content and 0.15 degree of quaternization. The stability of the membranes in alkaline media was evaluated using FTIR and TGA. It was shown that samples with a DAP content of more than 0.3 lost their integrity probably owing to partial hydrolysis of imide rings, while copolyimides with a DAP content of 0.2 and 0.3 remained stable.

• Publikační typ
• časopisecké články MeSH

BACKGROUND: Venotonics are a class of therapeutically active molecules that have vaso-protective effects. They are used to alleviate venous diseases and disorders, particularly venous insufficiency. We compared the composition of prescription versus over-the-counter (OTC) venotonics using high-performance liquid chromatography with UV detection (HPLC-DAD) and simulating their digestion using a static digestive model. METHODS: From each drug, five tablets were weighed. A homogenate was prepared, and 25 mg of crushed homogenized tablets were weighed into 25 ml volumetric flasks. Dissolved in MeOH and added two drops of saturated NaOH solution. The samples were filtered into vials (Teflon, 0.45 μm) and used for analysis. An Ultimate 3000 HPLC system (Thermo Fisher Scientific, Waltham, MA, USA) consisting of a quaternization pump, autosampler, column thermostat and DAD (UV/VIS detector) was used. The composition of the mobile phase proceeded in a linear gradient from 30% methanol and 70% phosphoric acid (0.15%) in water at time t=0 min. to 80% methanol and 20% phosphoric acid (0.15%) at time t=15 min., at a constant mobile phase flow rate of 1.2 mL/min. Detection was performed using a DAD detector in the 190-450 nm wavelength range. The content of monitored flavonoids was calculated from peaks at a wavelength of 277 nm, in which both flavonoids have their absorption maxima. The static digestive model was used to simulate the digestive phase from the oral cavity to the corresponding intestinal phase. RESULTS: The content of diosmin and hesperidin (mg per table) for a prescription drug: Detralex: 480 mg, 26 mg. The content of diosmin and hesperidin (mg per tablet) for OTC drugs: Venostop: 502 mg, 48 mg, Diosminol: 520 mg, 50 mg, Devenal: 496 mg, 49 mg, Diohes: 493 mg, 46 mg. Digestion did not affect the solubility of all tested drugs. The active substances could not be determined in the non-alkalized sample. After alkalization, part of the insoluble matter was visibly dissolved and converted to a yellow flavonoid complex. Neither diosmin nor hesperidin could be identified afterwards. CONCLUSIONS: Our experimental results show that the contents of both listed active substances, diosmin and hesperidin, met the declared amounts in all tested medicaments. Digestion simulation showed identical behaviour in prescription and OTC venotonics. The active substances could not be determined in the non-alkalized sample. Digestion did not affect the solubility of the tested drugs.

• MeSH
• biologické modely MeSH
• diosmin analýza   MeSH
• hesperidin analýza   MeSH
• léky bez předpisu * chemie   MeSH
• léky na předpis analýza   chemie   MeSH
• lidé MeSH
• tablety MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• diosmin MeSH
• hesperidin MeSH
• léky bez předpisu * MeSH
• léky na předpis MeSH
• tablety MeSH

The escalating antibiotic resistance observed in bacteria poses a significant threat to society, with the global prevalence of resistant strains of Pseudomonas aeruginosa on the rise. Addressing this challenge necessitates exploring strategies that would complement existing antimicrobial agents, e.g. by substances mitigating bacterial virulence without eliciting selective pressure for resistance emergence. In this respect, free-form chitosan has demonstrated promising efficacy, prompting our investigation into reinforcing its effects through nanoparticle formulations. Our study focuses on the preparation of chitosan nanoparticles under suitable conditions while emphasizing the challenges associated with stability that can affect biological activity. These challenges are mitigated by introducing quaternized chitosan, which ensures colloidal stability in the culture media. Our approach led to the production of trimethylchitosan nanoparticles with a median size of 103 nm, circularity of 0.967, and a charge of 14.9 ± 3.1 mV, stable within a one-month period in a water stock solution, showing promising attributes for further valorization. Furthermore, the study delves into the antimicrobial activity of trimethylchitosan nanoparticles on Pseudomonas aeruginosa and confirms the benefits of both nanoformulation and modification of chitosan, as our prepared nanoparticles inhibit 50% of the bacterial population at concentration ≥160 mg L-1 within tested strains. Additionally, we identified a concentration of 5 mg L-1 that no longer impedes bacterial growth, allowing reliable verification of the effect of the prepared nanoparticles on Pseudomonas aeruginosa virulence factors, including motility, protease activity, hemolytic activity, rhamnolipids, pyocyanin, and biofilm production. Although trimethylchitosan nanoparticles exhibit promise as an effective antibiofilm agent (reducing biofilm development by 50% at concentrations ranging from 80 to 160 mg L-1) their impact on virulence manifestation is likely not directly associated with quorum sensing. Instead, it can probably be attributed to non-specific interactions with the bacterial surface. This exploration provides valuable insights into the potential of quaternized chitosan nanoparticles in addressing Pseudomonas aeruginosa infections and underscores the multifaceted nature of their antimicrobial effects.

• Publikační typ
• časopisecké články MeSH

Stimuli-responsive copolymers are of great interest for targeted drug delivery. This study reports on a controllable post-polymerization quaternization with 2-bromomethyl-4-fluorophenylboronic acid of the poly(4-vinyl pyridine) (P4VP) block of a common poly(styrene)-b-poly(4-vinyl pyridine)-b-poly(ethylene oxide) (SVE) triblock terpolymer in order to achieve a selective responsivity to various diols. For this purpose, a reproducible method was established for P4VP block quaternization at a defined ratio, confirming the reaction yield by 11B, 1H NMR. Then, a reproducible self-assembly protocol is designed for preparing stable micelles from functionalized stimuli-responsive triblock terpolymers, which are characterized by light scattering and by cryogenic transmission electron microscopy. In addition, UV-Vis spectroscopy is used to monitor the boron-ester bonding and hydrolysis with alizarin as a model drug and to study encapsulation and release of this drug, induced by sensing with three geminal diols: fructose, galactose and ascorbic acid. The obtained results show that only the latter, with the vicinal diol group on sp2-hybridized carbons, was efficient for alizarin release. Therefore, the post-polymerization method for triblock terpolymer functionalization presented in this study allows for preparation of specific stimuli-responsive systems with a high potential for targeted drug delivery, especially for cancer treatment.

• Klíčová slova
• alizarin, drug delivery systems, micelles, poly(4-vinyl pyridine), poly(styrene)-b-poly(4-vinyl pyridine)-b-poly(ethylene oxide) terpolymer, quaternization,
• Publikační typ
• časopisecké články MeSH

Layer-by-layer (LbL) polyelectrolyte coatings are intensively studied as reservoirs of bioactive proteins for modulating interactions between biomaterial surfaces and cells. Mild conditions for the incorporation of growth factors into delivery systems are required to maintain protein bioactivity. Here, we present LbL films composed of water-soluble N-[(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride (HTCC), heparin (Hep), and tannic acid (TA) fabricated under physiological conditions with the ability to release heparin-binding proteins. Surface plasmon resonance analysis showed that the films formed on an anchoring HTCC/TA bilayer, with TA serving as a physical crosslinker, were more stable during their assembly, leading to increased film thickness and increased protein release. X-ray reflectivity measurements confirmed intermixing of the deposited layers. Protein release also increased when the proteins were present as an integral part of the Hep layers rather than as individual protein layers. The 4-week release pattern depended on the protein type; VEGF, CXCL12, and TGF-β1 exhibited a typical high initial release, whereas FGF-2 was sustainably released over 4 weeks. Notably, the films were nontoxic, and the released proteins retained their bioactivity, as demonstrated by the intensive chemotaxis of T-lymphocytes in response to the released CXCL12. Therefore, the proposed LbL films are promising biomaterial coating candidates for stimulating cellular responses.

• MeSH
• biokompatibilní materiály MeSH
• chitosan * MeSH
• heparin MeSH
• polyelektrolyty MeSH
• proteiny MeSH
• taniny MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biokompatibilní materiály MeSH
• chitosan * MeSH
• heparin MeSH
• polyelektrolyty MeSH
• proteiny MeSH
• taniny MeSH

Fluorescent carbon dots (CDs) are potential tools for the labeling of cells with many advantages such as photostability, multicolor emission, small size, rapid uptake, biocompatibility, and easy preparation. Affinity towards organelles can be influenced by the surface properties of CDs which affect the interaction with the cell and cytoplasmic distribution. Organelle targeting by carbon dots is promising for anticancer treatment; thus, intracellular trafficking and cytotoxicity of cationic CDs was investigated. Based on our previous study, we used quaternized carbon dots (QCDs) for treatment and monitoring the behavior of two human cancer cell MCF-7 and HeLa lines. We found similarities between human cancer cells and mouse fibroblasts in the case of QCDs uptake. Time lapse microscopy of QCDs-labeled MCF-7 cells showed that cells are dying during the first two hours, faster at lower doses than at higher ones. QCDs at a concentration of 100 µg/mL entered into the nucleus before cellular death; however, at a dose of 200 µg/mL, blebbing of the cellular membrane occurred, with a subsequent penetration of QCDs into the nuclear area. In the case of HeLa cells, the dose-depended effect did not happen; however, the labeled cells were also dying in mitosis and genotoxicity occurred nearly at all doses. Moreover, contrasted intracellular compartments, probably mitochondria, were obvious after 24 h incubation with 100 µg/mL of QCDs. The levels of reactive oxygen species (ROS) slightly increased after 24 h, depending on the concentration, thus the genotoxicity was likely evoked by the nanomaterial. A decrease in viability did not reach IC 50 as the DNA damage was probably partly repaired in the prolonged G0/G1 phase of the cell cycle. Thus, the defects in the G2/M phase may have allowed a damaged cell to enter mitosis and undergo apoptosis. The anticancer effect in both cell lines was manifested mainly through genotoxicity.

• Klíčová slova
• HeLa, MCF-7, cancer cells, cationic carbon dots, cytotoxicity, fluorescence microspectroscopy, genotoxicity, nucleus,
• MeSH
• biologický transport MeSH
• buněčné linie MeSH
• časosběrné zobrazování metody   MeSH
• fibroblasty cytologie   účinky léků   metabolismus   MeSH
• HeLa buňky MeSH
• kontrolní body fáze G2 buněčného cyklu účinky léků   MeSH
• kvantové tečky chemie   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• myši MeSH
• nádory farmakoterapie   genetika   metabolismus   MeSH
• optické zobrazování MeSH
• poškození DNA MeSH
• proliferace buněk MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• uhlík chemie   farmakokinetika   farmakologie   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• reaktivní formy kyslíku MeSH
• uhlík MeSH

HYPOTHESIS: Development of highly efficient low-molecular weight gelators (LMWGs) for safe energy storage materials is of great demand. Energy storage materials as fuel gels are often achieved by construction of hybrid organic frameworks capable of multiple noncovalent interactions in self-assembly, which allow tuning required properties at the molecular level by altering individual building blocks of the LMWG. However, LMWGs have limited rechargeable capability due to their chemical instability. EXPERIMENTS: We designed, synthesized and characterized a novel, bio-inspired chiral gemini amphiphile derivative 1 containing N-hexadecyl aliphatic tails from quaternized nicotinamide-based segment and bromide anion showing supergelation ability in water, alcohols, aprotic polar and aromatic solvents, with critical gel concentrations as low as 0.1 and 0.035 wt% in isopropanol and water, respectively. FINDINGS: Nanostructural architecture of the network depended on the solvent used and showed variations in size and shape of 1D nanofibers. Supergelation is attributed to a unique asymmetric NH⋯OC, H⋯Br- hydrogen bonding pattern between H-2 hydrogens from nicotinamide-based segment, amide functional groups from chiral trans-cyclohexane-1,2-diamide-based segment and bromide ions, supporting the intermolecular amide-amide interactions appearing across one strand of the self-assembly. Gels formed from 1 exhibit high stiffness, self-healing, moldable and colorable properties. In addition, isopropanol gels of 1 are attractive as reusable, shape-persistent non-toxic fuels maintaining the chemical structure with gelation efficiency for at least five consecutive burning cycles.

• Klíčová slova
• Circular dichroism, DFT calculations, Fuel gel, Low-molecular weight gelators, Nicotinamide derivative, Supergelation,
• MeSH
• gely MeSH
• molekulová hmotnost MeSH
• niacinamid * MeSH
• rozpouštědla MeSH
• vodíková vazba MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• gely MeSH
• niacinamid * MeSH
• rozpouštědla MeSH

Nine chromophores with ferrocene donor and pyridine/pyridinium acceptors have been prepared and further investigated. The performed X-ray analysis showed partially polarized and geometrically oblate pyridine unit. An extension of the π-system and N-quaternization were revealed as suitable tools for exclusive manipulation of the LUMO with the almost steady HOMO. Whereas the electrochemical HOMO-LUMO gap can be tuned from 3.01 to 1.49 eV, the high- and low-energy absorption bands were found within the range of 280-402/456-547 nm. The pyridinium chromophores showed distinct negative solvatochromism. A thorough DFT analysis has been performed; it turned out that ferrocene donor is capable of two principal D-A interactions, whose employment depends on the appended electron-withdrawing moiety.

• Publikační typ
• časopisecké články MeSH