In this contribution, a hydrophobically modified polysaccharide derivative is synthesized in an eco-friendly solvent water by conjugation of benzylamine with the backbone of the biopolymer. Owing to the presence of aromatic moieties, the resulting water-soluble polysaccharide derivative self-assembles spontaneously and selectively from solution on the surface of nanometric thin films and sheets of polystyrene (PS). The synthetic polymer modified in this way bears a biocompatible nanolayer suitable for the immobilization of horseradish peroxidase (HRP), a heme-containing metalloenzyme often employed in biocatalysis and biosensors. Besides the detailed characterization of the polysaccharide derivative, a quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM) are used to investigate the binding efficiency and interaction of HRP with the tailored polysaccharide interfaces. Subsequent enzyme activity tests reveal details of the interaction of HRP with the solid support. The novel polysaccharide derivative and its use as a material for the selective modification of PS lead to a beneficial, hydrophilic environment for HRP, resulting in high enzymatic activities and a stable immobilization of the enzyme for biocatalytic and analytic purposes.
COBISS.SI-ID: 18853398
As there is a large gap in the field of fibre microbiological testing, the successful establishment of appropriate techniques is extremely appreciated. Antimicrobials prevent bacterial cell division by damaging the cell wall or affecting the permeabilities of cells’ membranes; they denature proteins, block enzyme activity, prevent cell survival, etc. Intracellular potassium cations are released by the inhibitions of pathogenic micro-organisms. Their quantitative determination enables monitoring of the bactericidal effect regarding antimicrobials. It can be used as an alternative technique for determining the inhibition of micro-organisms in contact with antimicrobial agents. Chitosan, a biodegradable natural polymer, possesses antimicrobial characteristics that depend on a number of factors such as the protonated amino groups’ quantities, degree of acetylation, molecular weight, solvents, etc. Over recent years chitosan has become extremely attractive for fibre functionalization usage. The aim of this paper was to apply spectrophotometry and potentiometry using potassium ion-selective electrode, respectively, for the quantitative analysis of potassium efflux, resulting from the degradation of micro-organisms’ membranes in contact with chitosan itself, as well as with cellulose fibres functionalised by chitosan.
COBISS.SI-ID: 18567958
Porous gelatin (GEL) cryogels were processed by spatiotemporal and temperature-controlled gelation and freezing-lyophilizaton process, followed by zero-length cross-linking, using different molarities of reagents (EDC and NHS) and reaction media (100% PBS or 20/80% PBS/EtOH mixture) for variable time extensions (1-24 h). In this way, tuneable cryogels with gradient micro-porosity (from 100 um to1000 um) were formed, being mainly influenced by cross-linkers concentration and EtOH addition. Later affect the pore morphology (from round to ellipsoid), consequently modulating the stead- state physiological swelling profile towards twice lower values (~ 600%) comparing to step-vice swelling of in 100% PBS-media cross-linked cryogels. Whilst the presence of EtOH decelerate the cross-linking kinetic by retaining cryogels micro-structure formed during freezing, the 100% PBS and higher EDC molarity resulted in ~40% cross-linking degree, being expressed as a thermal resistance of cryogels up to ~73 °C. Finally, the tuneable enzymatic resistance allow time-dependent poly-L-Lysine (pL) release profile in up to month period. The processed GEL cryogels have potential in broad range biomedical applications, especially as sustainable, protein-based-drug delivery systems.
COBISS.SI-ID: 17920790
Numerous sources provide evidence of decorating textiles by reserving and dyeing, one of the techniques being blue-printing. Unfortunately, textile material´s fragment are subject to external influences; therefore, only a few textile exhibits have been preserved. In order to understand and preserve cultural heritage, it is very important to examine the representative samples of existing textile exhibits by using non-destructive methods. This study presents the results of measuring textile-physical properties of blue-printed textiles. We analysed material composition, weaving types, fabric density, twist direction, fabric thickness, yarn diameter and mass per unit area. Furthermore, analyses were conducted of colour characteristics regarding blue-printed textile exhibits. The results of both analyses served for the creation of qualitative replicas of blue-printed textile exhibits produced with the technique of modern digital printing with reactive dyes. Based on the results obtained using textile-physical measurements, the most suitable modern textile materials were selected and based on the results obtained from colour characteristics, the most suitable colours for digital printing were chosen. The resulting prints were re-evaluated, whereby the replicas were proved to sufficiently correspond to the original. The replicas of blue printed textiles are intended for museums for their exhibition needs, the making of missing pieces or entire textiles, for folklore purposes, as well as for the marketing of high-quality souvenirs, and the production of marketable clothes and home textiles with the elements of cultural heritage.
COBISS.SI-ID: 3120752
Mercaptopropyl-coated cobalt ferrite (CoFe2O4) magnetic nanoparticles synthesized using the co-precipitation method and surface modified using the Stöber method were investigated as a convenient and effective adsorbent for aqueous Hg2+ ions. The surfaces of the colloidal-CoFe2O4 nanoparticles were functionalized with tetraethoxysilane and 3-mercaptopropyltrimethoxysilane via the co-condensation process. The characteristics of these particles were assessed at different stages of the production process using X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, and vibrating-sample magnetometry. The adsorption capacity of the mercaptopropyl-coated CoFe2O4 nanoparticles with respect to the aqueous Hg2+ ions was evaluated using atomic absorption spectrometer. It was found that the pH value of the model solution, the mass of the adsorbent, the temperature and the time of the adsorption significantly influence the sorption of Hg2+ ions on the mercaptopropyl-coated cobalt ferrite nanoparticles. The maximum removal efficiency of the aqueous Hg2+ ions was 97 % at room temperature and neutral pH value.
COBISS.SI-ID: 18375958