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[en] Citrinin (CIT) is a nephrotoxic mycotoxin produced by several Aspergillus, Penicillium and Monascus species. CIT is unavoidable contaminant of different foods and drinks due to its wide occurrence and high thermal stability. For this reason, development of new, more sensitive analytical methods and decontamination strategies has high importance. In our study, the complex formation of CIT with native and chemically modified cyclodextrins was investigated using fluorescence spectroscopy. Furthermore, thermodynamic and molecular modeling studies were also performed for the deeper understanding of these host-guest interactions. Our results show that among the tested compounds methylated β-cyclodextrins form the most stable complexes with CIT and these derivatives cause the highest fluorescence enhancement of CIT as well. These observations recommend that some of the chemically modified derivatives show more favourable properties than the native cyclodextrin, and suggesting more promising analytical applicability and higher affinity as potential toxin binders.
[en] The review addresses the application of synthetic oligosaccharides related to fragments of capsular polysaccharides from different serotypes of the bacterium Streptococcus pneumoniae for the design of third-generation pneumococcal conjugate vaccines. Special focus is given to characteristic features of the chemical structures of oligosaccharides required for the induction of the protective immune response when using synthetic glycoconjugate vaccines based on oligosaccharide ligands and carrier proteins. The bibliography includes 101 references
[en] Ternary complexes of bismuth nanoparticles with β-cyclodextrin and polyvinylpyrrolidone are studied via UV and visible spectroscopy and dynamic light scattering. It is shown that, depending on the ratio of the concentrations of β-cyclodextrin to polyvinylpyrrolidone in a synthetic medium, bismuth nanoparticles can be stabilized sterically either by distributing polyvinylpyrrolidone molecules over the surface of a complex of nanoparticles with β-cyclodextrin or by forming inclusion complexes of nanoparticles in the hydrophobic cavity of β-cyclodextrin as a result of associated β-cyclodextrin molecules being pushed apart by polyvinylpyrrolidone molecules. The conditions are determined for the formation of ternary complexes that are aggregatively stable for 20 days and are characterized by a unimodal particle size distribution.
[en] Three-dimensional (3D) designed hydrogels are receiving considerable attention for use in tissue engineering. Herein, we present a novel method for bioprinting 3D hydrogels by electrodeposition with a pin art device. The device consists of a metal substrate and an array of electrode pins that can slide independently. To fabricate a 3D-hydrogel, pins are pushed from the rear with a 3D object to generate a 3D extruded-pin relief of the object; the extruded pins are then inserted into a chitosan/gelatin hydrogel. Due to H+ consumption at these pins, which collectively act as a cathode, the protonated amino groups of the chitosan become deprotonated, which results in the electrodeposition of the chitosan bound to the gelatin onto the extruded pins. The untreated hydrogel is removed by heating to provide the 3D-designed chitosan/gelatin hydrogel. As a proof of concept, hydrogels of various shapes were fabricated. In addition, cells were successfully cultured in a hydrogel, highlighting its biocompatibility. This method is useful for constructing 3D artificial tissue consisting of hydrogels and cells. (paper)
[en] Oligosaccharides on proteins and lipids play central roles in human health and disease. The molecular analysis of glycoconjugate function has benefited tremendously from new methods for their chemical synthesis, which provides homogeneous material not attainable from biosynthetic systems. Still, glycoconjugate synthesis requires the manipulation of multiple stereocenters and protecting groups and remains the domain of a few expert laboratories around the world. This account summarizes chemoselective approaches for assembling homogeneous glycoconjugates that attempt to reduce the barriers to their synthesis. The objective of these methods is to make glycoconjugate synthesis accessible to a broader community, thereby accelerating progress in glycobiology
[en] Chitosan/tripolyphosphate polyelectrolyte (TPP) microspheres, decorated and surface functionalized with silver nanoparticles (NPs) of average diameter of 15 nm, were synthesized following a simple two-step procedure. These Ag NP-functionalized polyelectrolyte microspheres (Ag-CSPMs) are found to be biocompatible and enhancing the reactive oxygen species in curcumin with excellent anti-bacterial activity for selected Gram-positive and negative bacterial strains, making them much attractive relative to bare surface counterparts; the well-stabilized silver NPs do not form any agglomerations on the surface of the chitosan microspheres. They also show excellent cytotoxic behavior towards MCF7 cell lines, showing a half-maximal inhibitory concentration (IC50) of 32 μg ml−1. Therefore, Ag-CSPMs exhibit multi-functional ability having potential towards theranostics applications. (paper)
[en] Inspired by the strong adhesive produced by English ivy, this paper proposes an in situ synthesis approach for fabricating tunable nanoparticle enhanced adhesives. Special attention was given to tunable features of the adhesive produced by the biological process. Parameters that may be used to tune properties of the adhesive will be proposed. To illustrate and validate the proposed approach, an experimental platform was presented for fabricating tunable chitosan adhesive enhanced by Au nanoparticles synthesized in situ. This study contributes to a bio-inspired approach for in situ synthesis of tunable nanocomposite adhesives by mimicking the natural biological processes of ivy adhesive synthesis. (paper)
[en] Highlights: ► Ternary diffusion coefficients for the systems KCl/βCD/H2O and KCl/HP-βCD/H2O. ► Influence of the KCl on diffusion of some cyclodextrins in the aqueous media. ► Estimation of the association constants of the complexes KCl/βCD and KCl/HP-βCD. - Abstract: Ternary mutual diffusion coefficients measured by the Taylor dispersion method (D11, D22, D12 and D21) are reported for two aqueous systems, that is, potassium chloride and 2-hydroxypropyl-β-cyclodextrin (HP-βCD), and potassium chloride and β-cyclodextrin (βCD) at T = 298.15 K and T = 310.15 K, and at carrier concentrations from (0.000 to 0.010) mol·dm−3 for each solute. Based on these data, some conclusions about the influence of KCl on the diffusion of the cyclodextrins (HP-βCD and βCD) were made, and the association constants of the complexes formed between the two components for each system (KCl and βCD, and KCl and HP-βCD) were estimated.