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In this work, new composite films were prepared by incorporating the disintegrated bacterial cellulose (BCd) nanofibers and cerium oxide nanoparticles into chitosan (CS) matrices. The influence of the amount of nanofillers on the structure and properties of the polymer composites and the specific features of the intermolecular interactions in the materials were determined. An increase in film stiffness was observed as a result of reinforcing the CS matrix with BCd nanofibers: the Young’s modulus increased from 4.55 to 6.3 GPa with the introduction of 5% BCd. A further increase in Young’s modulus of 6.7 GPa and a significant increase in film strength (22% increase in yield stress compared to the CS film) were observed when the BCd concentration was increased to 20%. The amount of nanosized ceria affected the structure of the composite, followed by a change in the hydrophilic properties and texture of the composite films. Increasing the amount of nanoceria to 8% significantly improved the biocompatibility of the films and their adhesion to the culture of mesenchymal stem cells. The obtained nanocomposite films combine a number of favorable properties (good mechanical strength in dry and swollen states, improved biocompatibility in relation to the culture of mesenchymal stem cells), which allows us to recommend them for use as a matrix material for the culture of mesenchymal stem cells and wound dressings.

In this paper, we report on novel polyimide (PI) nanocomposites filled with binary mixtures of metal oxide (either TiO2 or ZrO2) nanoparticles and nanocarbon (either carbon nanofibers (CNFs) or functionalized carbon nanotubes (CNTfs)). The structure and morphology of the materials obtained were comprehensively studied. An exhaustive investigation of their thermal and mechanical properties was performed. We revealed a synergistic effect of the nanoconstituents with regard to a number of functional characteristics of the PIs compared with single-filler nanocomposites, including thermal stability, stiffness (below and above glass transition temperature), yield point, and temperature of flowing. Moreover, the possibility of manipulating the properties of the materials by choosing a proper combination of the nanofillers was demonstrated. The results obtained can become a platform in the design of PI-based engineering materials with tailored characteristics capable of operating in extreme conditions.

Polymeric drug delivery systems enhance the biopharmaceutical properties of antibiotics by increasing their bioavailability, providing programmable and controlled-release properties, and reducing toxicity. In addition, drug delivery systems are a promising strategy to improve the intestinal permeability of various antimicrobial agents, including colistin (CT). This study describes the modification of conjugates based on CT and hyaluronic acid (HA) with cyanocobalamin (vitamin B12). Vitamin B12 was chosen as a targeting ligand because it has its own absorption pathway in the small intestine. The resulting polysaccharide conjugates contained 95 μg/mg vitamin B12 and the CT content was 335 μg/mg; they consisted of particles of two sizes, 98 and 702 nm, with a ζ-potential of approximately −25 mV. An in vitro release test at pH 7.4 and pH 5.2 showed an ultra-slow release of colistin of approximately 1% after 10 h. The modified B12 conjugates retained their antimicrobial activity at the level of pure CT (minimum inhibitory concentration was 2 μg/mL). The resulting delivery systems also reduced the nephrotoxicity of CT by 30–40% (HEK 293 cell line). In addition, the modification of B12 improved the intestinal permeability of CT, and the apparent permeability coefficient of HA–CT–B12 conjugates was 3.5 × 10−6 cm/s, corresponding to an in vivo intestinal absorption of 50–100%. Thus, vitamin-B12-modified conjugates based on CT and HA may be promising oral delivery systems with improved biopharmaceutical properties.

A group of new hydrogel materials combining high physical properties and pronounced antibacterial activity has been developed. These are composite hydrogels “cellulose-polyacrylamide” based on cellulose matrices of two types: bacterial or regenerated plant cellulose. To form biologically active materials, a method of introducing cerium oxide nanoparticles with sizes less than 5 nm was elaborated. The developed technology allows to obtain hydrogels with the content of cerium oxide (in swollen material) up to 0.4–0.5 wt%. Variations of the ratio of gel components concentrations, type of matrix cellulose and synthesis conditions allow to change the complex of mechanical properties of the material within a wide range, in particular, to obtain both soft, low-modular nanocomposites and hydrogels with record high rigidity. Significant differences in mechanical properties of hydrogels based on different types of cellulose fully correlate with the difference in morphological characteristics of these two groups of materials, revealed by SEM. No palpable effect of nanoparticles on the morphological characteristics of the material was revealed. Both cerium oxide nanoparticles and hydrogels containing cerium oxide showed antibacterial activity against S. aureus ATCC 29213, S. aureus ATCC 43300, P. aeruginosa ATCC 27853, K. pneumoniae ATCC 33495. Different intensity of growth depression of the bacterial cells was determined depending on the samples composition and of the bacteria species.

Cellulose nanofibers (CNF) produced by bacterial were functionalized along the surface with 3-(trimethoxysilyl)propyl methacrylate (TMSPM). The chemical and crystalline structure of the material was confirmed with NMR, FTIR, EDX and XRD methods. Modified CNF were used as a crosslinker and reinforcer for polymerizable deep eutectic solvent (DES) based on acrylic acid and choline chloride. Dispersions of modified nanofibers in DES were applied as UV-curable ink for 3D printing. It was shown that shielding of -OH groups of the cellulose surface with TMSPM increased the quality of 3D printed filaments due to reduced CNF agglomeration. At the same time, surface methacrylic groups copolymerize with acrylic acid forming crosslinked ion gel. Elastic moduli of the prepared ion gels were identical to those of gels based on unmodified CNF and crosslinked with N,N'-methylenebisacrylamide. However, strength and the ultimate elongation of the material prepared in this work were 1.05 ± 0.08 MPa at 2700% that is significantly higher than those of the material prepared with unmodified CNF.

The covalent conjugation of pharmaceutical compounds to polymeric carriers represents an effective strategy for enhancing drug properties, including improved bioavailability, targeted delivery, and sustained release, while reducing systemic toxicity and adverse effects. By exploiting the physicochemical characteristics of biopolymers—particularly molecular charge and weight—we engineered a polymeric platform for glucocorticoid delivery with precisely controlled parameters including particle size, surface charge, targeting capability, and release kinetics. This study reports a linker-free synthesis of hyaluronic acid-dexamethasone (HA-DEX) conjugates through Steglich esterification, catalyzed by 4-dimethylaminopyridine (DMAP), which facilitates the acylation of sterically hindered alcohols. The reaction specifically couples carboxyl groups of hyaluronic acid with the C21 hydroxyl group of dexamethasone. Incorporation of hydrophobic dexamethasone moieties induced self-assembly into nanoparticles featuring a hydrophobic core and negatively charged hydrophilic shell (−20 to −25 mV ζ-potential). In vitro characterization revealed pH-dependent release profiles, with 80–90% dexamethasone liberated in mildly acidic phosphate buffer (pH 5.2) versus 50–60% in phosphate-buffered saline (pH 7.4) over 35 days, demonstrating both sustained release and inflammation-responsive behavior. The conjugates exhibited potent anti-inflammatory activity in a human tumor necrosis factor-α (TNFα)-induced inflammation model. These findings position HA-DEX conjugates as promising candidates for targeted glucocorticoid delivery to specific anatomical sites including ocular, articular, and tympanic tissues, where their combination of CD44-targeting capability, enhanced permeability and retention effects, and stimulus-responsive release can optimize therapeutic outcomes while minimizing off-target effects.

New aromatic co-polyamide-imides (coPAIs) containing both carboxyl and hydroxyl groups in the repeating units were synthesized for the first time. Transport, thermal and morphological properties of dense nonporous membranes from PAIs obtained using the diacid chloride of 2-(4-carboxyphenyl)-1,3-dioxoisoindoline-5-carboxylic acid and diamines 5,5′-methylene-bis (2-aminophenol)) and 3,5-Diaminobenzoic acid, taken in molar ratios of 7:3, 1:1, and 3:7, have been studied. High levels of membrane permeability accompanied by high selectivity for mixtures of liquids with significantly different polarities were determined by realization of intra- and intermolecular interactions in polymer, which was proved by thermal analyses and hydrodynamic characteristics of coPAIs. This effect is discussed in the context of the effectiveness of intermolecular interactions between polymer chains containing carboxyl and hydroxyl functional groups.

The structural features and thermophysical and transport properties of dense nonporous membranes of the casting type from (co)polyamide-imides synthesized by the polycondensation of the diacid chloride of 2-(4-carboxyphenyl)-1,3-dioxoisoindoline-5-carboxylic acid and diamines 5,5′-methylene-bis (2-aminophenol) (DADHyDPhM) and 4,4′-methylenebis(benzeneamine) (DADPhM), taken in molar ratios of 7:3, 1:1, and 3:7, have been studied. The effect of hydroxyl-containing modifying fragments of dihydroxy diphenylmethane introduced in various amounts into the main polymer chain on the pervaporation properties of the formed films is discussed. It has been shown that the presence of the residual solvent N-methyl-2-pyrrolidone in the films not only has a plasticizing effect on the characteristics of film membranes but also promotes the preferential transmembrane transport of polar liquids, primarily methanol (permeation rate over 2 kg for a copolymer with a ratio of DADHyDPhM:DADPhM = 7:3). The removal of the residual solvent from the polymer film, both thermally (heating to 200 °C) and by displacement with another solvent as a result of sequential pervaporation, led to a significant decrease in the rate of transfer of polar liquids and a decrease in the selectivity of the membrane. However, the dehydrocyclization reaction resulted in more brittle films with low permeability to penetrants of different polarities. The results of our comprehensive study made it possible to assume the decisive influence of structural changes in membranes occurring in connection with the competitive formation of intra- and intermolecular hydrogen bonds.

Abstract Optically active nanobiocolloids (NBC) containing plasmonic nanoparticles (NP) covered by helical biomacromolecules are interesting for various theranostic applications. We report the study of NBC colloids containing from 4.4 to 9.3 w/w % of small (ca. 10 nm) spherical AgNPs covered by polygalacturonic acid (PGA). The AgNPs were obtained by reduction of silver ions with the functional groups of PGA. The NBC structure was formed by nanoprecipitation of the final solution into an anti-solvent (ethanol) bath. The NBC powders were characterized by transmission electron and atomic force (AFM) microscopies, FT-IR, and X-ray diffraction. The FT-IR analysis showed that the carboxylate groups of PGA were attached to the AgNPs’ surface by bidentate binding. The PGA (the major constituent of the main chain of pectins) is a weak anionic polysaccharide which helical conformations and their self-assembly depend on the deprotonation of carboxyl groups. We studied how pH influences the form, size, depolarization of scattered light, and chiroplasmonic properties of NBC. The optical rotatory dispersion of NBC exhibited plasmonically enhanced Cotton effect related to helical PGA macromolecules capped to AgNPs. The Cotton effect changed its sign from negative (at pH 4.01) to positive (at pH 6.86) implying the inversion of handedness of the PGA helixes. By using dynamic and depolarized dynamic light scattering, the effective hydrodynamic radii were calculated for translational (Rh) and rotational (Rrot) diffusion. Their characteristic ratio Rrot/Rh expressed in terms of the Perrin frictional coefficients showed that the form of NBC colloids changed from spherical to elongated with decreasing pH. The elongated form in the acidic buffer was attributed to the side-by-side stacking of the helical segments of PGA. Low fraction of coupled plasmons and plasmonic enhancement of elliptical polarization of light by the helical conformers of PGA were both responsible for high depolarization of light scattered by NBC colloids. The highest depolarization degree of 40% observed in the acidic buffer was ascribed to the non-uniform elliptical shell of PGA around AgNPs. Contrary to the pristine particles of sodium polygalacturonate (PGA@Na), the NBC retained their size upon drying, as shown by AFM. In accord, comparison of the FT-IR spectra of NBC and PGA@Na showed that the NBC were stabilized by additional hydrogen bonds.

One of the main strategies for improving the efficiency of agricultural production is the use of fertilisers with slow or controlled release of nutrients, in which the granules of mineral fertilisers are covered with polymeric shells. The composition of the polymer coatings of mineral fertiliser granules with slow or controlled release of two widespread manufacturers and their ability to adsorb some heavy metal ions on their surface were examined in this study. It was found that the base polymers used to encapsulate the fertilisers studied are the co-polymer polyethylene–polyacrylic acid in the Brand A, and polyacrylamide, polyacrylic acid, and its esters in the Brand B fertiliser coating. The maximum adsorption rate of heavy metal ions on the surface of the polymer coatings with the rest of the mineral filler of Brand A and Brand B fertilisers was 54.64 and 28.90 mg/g for Cd(II) ions, 30.77 and 14.03 mg/g for Pb(II) ions, respectively. Therefore, the solution to the problem of increasing the efficiency of agricultural production through the use of fertilisers with slow or controlled release of nutrients leads to environmental pollution by microplastics remaining in the soil after fertiliser application, which are also capable of adsorbing from the soil various toxic pollutants.