Advances in Applications of Polysaccharides and Polysaccharide-Based Materials.

Polysaccharides, complex carbohydrates composed of long chains of residues of sugar molecules, have garnered significant attention in recent years due to their diverse applications across various industries [...].

Polysaccharide-based films: from packaging materials to functional food.

A wider application of naturally derived polysaccharides is of great interest as materials for food packaging industry. Biocompatibility and biodegradability of polysaccharide-based films and coatings ally with a shift from application of non-biodegradable petrochemical polymers to the more environmentally friendly ones. Due to a range of inherent features in chemical structure and bioactivity, the polysaccharide materials could bring additional functionality to food packaging. The chelating ability of the polysaccharides provides also their application as carriers of additional active components, such as nanoparticles, essential oils and polyphenols. The improved physicochemical, antibacterial and antioxidant properties of the filled films allows to consider the edible polysaccharide-based films as functional food products. This review is aimed at analysis of evolution of polysaccharide-based food packaging materials from inert one starting from cellophane to recent research works on development of multicomponent polysaccharide-based functional food films and coatings.

A π-Stacking Based Fluorescent Probe for Labeling of Flavin Analogues in Live Cells through Unusual FRET Process.

The flavin adenine dinucleotide (FAD) is an indispensable coenzyme in live cells. It acts as a catalyst in many redox responsive metabolic reactions, including oxidative phosphorylation in mitochondria. The real-time monitoring of flavin is important to understand the disorder in the metabolic process, redox system, etc. Thus, we have developed a fluorescent probe CPy-1 that noncovalently binds with flavin to exhibit the FRET process. 1H- NMR and docking study indicated that there is a strong hydrophobic interaction between flavins and CPy-1. Also, a π-π stacking between isoalloxazine ring in flavin and quinoline and coumarin moieties of CPy-1 favors self-assembly. The nontoxic probe CPy-1 could distinguish cancer cells from normal cells based on expressions of endogenous FAD.

Mechanochemical Transformations of Polysaccharides: A Systematic Review.

Taking into consideration the items of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), this study reviews application of mechanochemical approaches to the modification of polysaccharides. The ability to avoid toxic solvents, initiators, or catalysts during processes is an important characteristic of the considered approach and is in line with current trends in the world. The mechanisms of chemical transformations in solid reactive systems during mechanical activation, the structure and physicochemical properties of the obtained products, their ability to dissolve and swell in different media, to form films and fibers, to self-organize in solution and stabilize nanodispersed inorganic particles and biologically active substances are considered using a number of polysaccharides and their derivatives as examples.

Biodegradable Cell Microcarriers Based on Chitosan/Polyester Graft-Copolymers.

Self-stabilizing biodegradable microcarriers were produced via an oil/water solvent evaporation technique using amphiphilic chitosan-g-polyester copolymers as a core material in oil phase without the addition of any emulsifier in aqueous phase. The total yield of the copolymer-based microparticles reached up to 79 wt. %, which is comparable to a yield achievable using traditional emulsifiers. The kinetics of microparticle self-stabilization, monitored during their process, were correlated to the migration of hydrophilic copolymer's moieties to the oil/water interface. With a favorable surface/volume ratio and the presence of bioadhesive natural fragments anchored to their surface, the performance of these novel microcarriers has been highlighted by evaluating cell morphology and proliferation within a week of cell cultivation in vitro.

Chitosan impregnation with biologically active tryaryl imidazoles in supercritical carbon dioxide.

The presented paper is focused on impregnation of chitosan and its derivatives with a biologically active triaryl imidazole model compound ((2-2-hydroxyphenyl)-4.5-diphenyl-1H-imidazole) in the supercritical carbon dioxide medium. Since initial chitosan represents a polycation-exchange resin and does not swell in supercritical carbon dioxide, the impregnation was carried out in the presence of water (0.15-3.0 vol%). The maximum 2-2-hydroxyphenyl)-4.5-diphenyl-1H-imidazole concentration in a chitosan film was achieved at the ~5 × 10(-3) g/cm(3) water content in the reactor. We also used hydroxy carboxylic acid derivatives of chitosan and its copolymer with polylactide as matrices for introduction of hydrophobic 2-2-hydroxyphenyl)-4.5-diphenyl-1H-imidazole. We have shown that unmodified chitosan contains the greatest amount of 2-2-hydroxyphenyl)-4.5-diphenyl-1H-imidazole, as compared with its hydrophobic derivatives. The kinetics of 2-2-hydroxyphenyl)-4.5-diphenyl-1H-imidazole diffusion from a chitosan matrix was studied in acidified water with pH 1.6. We found that the complete release of 2-2-hydroxyphenyl)-4.5-diphenyl-1H-imidazole into the aqueous phase from unmodified chitosan films occurred in 48 h, while its complete release from chitosan modified with hydroxy carboxylic acids occurred in 5 min or less.

Fibroblasts and polymer composition are essential for bioengineering of airway epithelium on nonwoven scaffolds.

To make tissue engineering a truly effective tool, it is necessary to understand how the patterns of specific tissue development are modulated by and depend on the artificial environment. Even the most advanced approaches still do not fully meet the requirements of practical engineering of tracheobronchial epithelium. This study aimed to test the ability of the synthetic and natural nonwoven scaffolds to support the formation of morphological sound airway epithelium including the basement membrane (BM). We also sought to identify the potential role of fibroblasts in this process. Our results showed that nonwoven scaffolds are generally suitable for producing well-differentiated tracheobronchial epithelium (with cilia and goblet cells), while the structure and functionality of the equivalents appeared to be highly dependent on the composition of the scaffolds. Unlike natural scaffolds, synthetic ones supported the formation of the epithelium only when epithelial cells were cocultured with fibroblasts. Fibroblasts also appeared to be obligatory for basal lamina formation, regardless of the type of the nonwoven material used. However, even in the presence of fibroblasts, the synthetic scaffolds were unable to support the formation of the epithelium and of the BM (in particular, basal lamina) as effectively as the natural scaffolds did.

New surface-enhanced Raman scattering platforms: composite calcium carbonate microspheres coated with astralen and silver nanoparticles.

Surface-enhanced Raman scattering (SERS) microspectroscopy is a very promising label-free, noncontact, and nondestructive method for real-time monitoring of extracellular matrix (ECM) development and cell integration in scaffolds for tissue engineering. Here, we prepare a new type of micrometer-sized SERS substrate, core-shell microparticles composed of solid carbonate core coated with silver nanoparticles and polyhedral multishell fullerene-like structure, astralen. Astralen has been assembled with polyallylamine hydrochloride (PAH) by the layer-by-layer manner followed by Ag nanoparticle formation by means of a silver mirror reaction, giving the final structure of composite particles CaCO3(PAH/astralen)x/Ag, where x = 1-3. The components of the microparticle carry multiple functionalities: (i) an easy identification by Raman imaging (photostable astralen) and (ii) SERS due to a rough surface of Ag nanoparticles. A combination of Ag and astralen nanoparticles provides an enhancement of astralen Raman signal by more than 1 order of magnitude. Raman signals of commonly used scaffold components such as polylactide and polyvinyl alcohol as well as ECM component (hyaluronic acid) are significantly enhanced. Thus, we demonstrate that new mechanically robust and easily detectable (by astralen signal or optically) core-shell microspheres based on biocompatible CaCO3 can be used as SERS platform. Particle design opens many future perspectives for fabrication of SERS platforms with multiple functions for biomedical applications, for example, for theranostic.

Universal Microcarriers Based on Natural and Synthetic Polymers for Co-Delivery of Hydrophilic and Hydrophobic Compounds.

Several variants of hybrid polyelectrolyte microcapsules (hPEMC) were designed and produced by modifying in situ gelation methods and layer-by-layer (LbL) techniques. All of the hPEMC designs tested in the study demonstrated high efficiency of the model hydrophilic compound loading into the carrier cavity. In addition, the microcarriers were characterized by high efficiency of incorporating the model hydrophobic compound rhodamine B isothiocyanate (RBITC) into the hydrophobic layer consisting of poly-(d,l)-lactide-co-glycolide (PLGA), oligo-(l)-lactide (OLL), oligo-(d)-lactide (OLD) and chitosan/gelatin/poly-l-lactide copolymer (CGP). The obtained microcapsules exhibited high storage stability regardless of the composition and thickness of the polyelectrolyte shell. Study of the impact of hybrid polyelectrolyte microcapsules on viability of the adhesive L929 and suspension HL-60 cell lines revealed no apparent toxic effects of hPEMC of different architecture on live cells. Interaction of hPEMC with peritoneal macrophages for the course of 48 h resulted in partial deformation and degradation of microcapsules accompanied by release of the content of their hydrophilic (BSA-fluorescein isothiocyanate conjugate (BSA-FITC)) and hydrophobic (RBITC) layer. Our results demonstrate the functional efficiency of novel hybrid microcarriers and their potential for joint delivery of drugs with different physico-chemical properties in complex therapy.

Biodegradable Microparticles for Regenerative Medicine: A State of the Art and Trends to Clinical Application.

Tissue engineering and cell therapy are very attractive in terms of potential applications but remain quite challenging regarding the clinical aspects. Amongst the different strategies proposed to facilitate their implementation in clinical practices, biodegradable microparticles have shown promising outcomes with several advantages and potentialities. This critical review aims to establish a survey of the most relevant materials and processing techniques to prepare these micro vehicles. Special attention will be paid to their main potential applications, considering the regulatory constraints and the relative easiness to implement their production at an industrial level to better evaluate their application in clinical practices.

Controlled Structure of Polyester/Hydroxyapatite Microparticles Fabricated via Pickering Emulsion Approach.

Biodegradable polyester/hydroxyapatite microparticles are widely proposed as microcarriers for drug/cell delivery or scaffolds for bone tissue regeneration. The current research implements the surfactant-free approach for the fabrication of polyester-based microparticles filled with hydroxyapatite nanoparticles (nHA) via the oil/water Pickering emulsion solvent evaporation technique for the first time, to the best of our knowledge. The process of polyester microparticle fabrication using nHA for the oil/water interface stabilization was studied as a function of phase used for nHA addition, which allows the preparation of a range of microparticles either filled with nHA or having it as a shell over the polymeric core. The effect of processing conditions (polymer nature, polymer/nHA ratio, ultrasound treatment) on particles' total yield, size distribution, surface and volume morphology, and chemical structure was analyzed using SEM, EDX, Raman spectroscopy, and mapping. Addition of nHA either within the aqueous or oil phase allowed the effective stabilization of the oil/water interface without additional molecular surfactants, giving rise to hybrid microparticles in which total yield, size distribution, and surface morphology depended on all studied processing conditions. Preliminary ultrasound treatment of any phase before the emulsification process led to a complex effect but did not affect the homogeneity of nHA distribution within the polymeric core of the hybrid microparticles.

Effective and Easy Techniques of Collagen Deposition onto Polylactide Films: DC-Discharge Plasma Treatment vs. Chemical Entrapment.

Enhancement of cell adhesion and growth on surface of the biodegradable materials is one of the important tasks in development of materials for regenerative medicine. This work focuses on comparison of various methods of collagen coating deposition onto polylactide films, aiming to increase their biocompatibility with human mesenchymal stromal cells. The collagen deposition was realized using either preliminary plasma treatment of the polylactide films or pre-swelling in solvent mixture. These techniques were compared in terms of the effect on the surface's chemical structure, morphology, hydrophilicity and ability to support adhesion and growth of human mesenchymal stromal cells.

Electrospinning vs. Electro-Assisted Solution Blow Spinning for Fabrication of Fibrous Scaffolds for Tissue Engineering.

Biodegradable polymeric fibrous non-woven materials are widely used type of scaffolds for tissue engineering. Their morphology and properties could be controlled by composition and fabrication technology. This work is aimed at development of fibrous scaffolds from a multicomponent polymeric system containing biodegradable synthetic (polylactide, polycaprolactone) and natural (gelatin, chitosan) components using different methods of non-woven mats fabrication: electrospinning and electro-assisted solution blow spinning. The effect of the fabrication technique of the fibrous materials onto their morphology and properties, including the ability to support adhesion and growth of cells, was evaluated. The mats fabricated using electrospinning technology consist of randomly oriented monofilament fibers, while application of solution blow spinning gave a rise to chaotically arranged multifilament fibers. Cytocompatibility of all fabricated fibrous mats was confirmed using in vitro analysis of metabolic activity, proliferative capacity and morphology of NIH 3T3 cell line. Live/Dead assay revealed the formation of the highest number of cell-cell contacts in the case of multifilament sample formed by electro-assisted solution blow spinning technology.

Hydrophobic Modification of Chitosan via Reactive Solvent-Free Extrusion.

Hydrophobic derivatives of polysaccharides possess an amphiphilic behavior and are widely used as rheological modifiers, selective sorbents, and stabilizers for compositions intended for various applications. In this work, we studied the mechanochemical reactions of chitosan alkylation when interacting with docosylglycidyl and hexadecylglycidyl ethers in the absence of solvents at shear deformation in a pilot twin-screw extruder. The chemical structure and physical properties of the obtained derivatives were characterized by elemental analysis, FT-IR spectroscopy, dynamic light scattering, scanning electron microscopy, and mechanical tests. According to calculations for products soluble in aqueous media, it was possible to introduce about 5-12 hydrophobic fragments per chitosan macromolecule with a degree of polymerization of 500-2000. The length of the carbon chain of the alkyl substituent significantly affects its reactivity under the chosen conditions of mechanochemical synthesis. It was shown that modification disturbs the packing ability of the macromolecules, resulting in an increase of plasticity and drop in the elastic modulus of the film made from the hydrophobically modified chitosan samples.

Polysaccharides as Stabilizers for Polymeric Microcarriers Fabrication.

Biodegradable polymeric microparticles are widely used in drug delivery systems with prolonged-release profiles and/or cell microcarriers. Their fabrication via the oil/water emulsion solvent evaporation technique has normally required emulsifiers in the aqueous phase. The present work aims to evaluate the effectiveness of various polysaccharides, such as chitosan, hyaluronic acid, cellulose, arabinogalactan, guar and their derivatives, as an alternative to synthetic surfactants for polylactide microparticle stabilization during their fabrication. Targeted modification of the biopolymer's chemical structure was also tested as a tool to enhance polysaccharides' emulsifying ability. The transformation of biomacromolecules into a form of nanoparticle via bottom-up or top-down methods and their subsequent application for microparticle fabrication via the Pickering emulsion solvent evaporation technique was useful as a one-step approach towards the preparation of core/shell microparticles. The effect of polysaccharides' chemical structure and the form of their application on the polylactide microparticles' total yield, size distribution and morphology was evaluated. The application of polysaccharides has great potential in terms of the development of green chemistry and the biocompatibility of the formed microparticles, which is especially important in biomedicine application.

Plasma Treatment of Poly(ethylene terephthalate) Films and Chitosan Deposition: DC- vs. AC-Discharge.

Plasma treatment is one of the most promising tools to control surface properties of materials tailored for biomedical application. Among a variety of processing conditions, such as the nature of the working gas and time of treatment, discharge type is rarely studied, because it is mainly fixed by equipment used. This study aimed to investigate the effect of discharge type (direct vs. alternated current) using air as the working gas on plasma treatment of poly(ethylene terephthalate) films, in terms of their surface chemical structure, morphology and properties using X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and contact angle measurements. The effect of the observed changes in terms of subsequent chitosan immobilization on plasma-treated films was also evaluated. The ability of native, plasma-treated and chitosan-coated films to support adhesion and growth of mesenchymal stem cells was studied to determine the practicability of this approach for the biomedical application of poly(ethylene terephthalate) films.

Multicomponent Non-Woven Fibrous Mats with Balanced Processing and Functional Properties.

The mimicking of the architectonics of native tissue, biodegradable non-woven fibrous mats is one of the most promising forms of scaffolding for tissue engineering. The key properties needed for their successful application in vivo, such as biodegradability, biocompatibility, morphology, mechanical properties, etc., rely on their composition and appropriate 3D structure. A multicomponent system based on biodegradable synthetic (polycaprolactone, oligo-/polylactide) and natural (chitosan, gelatin) polymers, providing the desired processing characteristics and functionality to non-woven mats fabricated via the electrospinning technique, was developed. The solid-state reactive blending of these components provided a one-step synthesis of amphiphilic graft copolymer with an ability to form stable ultra-fine dispersions in chlorinated solvents, which could be successfully used as casting solvents for the electrospinning technique. The synthesized graft copolymer was analyzed with the aim of fractional analysis, dynamic laser scattering, FTIR-spectroscopy and DSC. Casting solution characteristics, namely viscosity, surface tension, and electroconductivity, as well as electrospinning parameters, were studied and optimized. The morphology, chemical structure of the surface layer, mechanical properties and cytocompatibility were analyzed to confirm the appropriate functionality of the formed fibrous materials as scaffolds for tissue engineering.

Solid-State Synthesis of Water-Soluble Chitosan-g-Hydroxyethyl Cellulose Copolymers.

Graft copolymers of chitosan with cellulose ether have been obtained by the solid-state reactive mixing of chitin, sodium hydroxide and hydroxyethyl cellulose under shear deformation in a pilot twin-screw extruder. The structure and composition of the products were determined by elemental analysis and IR spectroscopy. The physicochemical properties of aqueous solutions of copolymers were studied as a function of the composition, and were correlated to the mechanical characteristics of the resulting films to assess the performance of new copolymers as coating materials, non-woven fibrous materials or emulsifiers for interface stabilization during the microparticle fabrication process.

Chitosan-g-oligo(L,L-lactide) Copolymer Hydrogel Potential for Neural Stem Cell Differentiation.

We evaluated the applicability of chitosan-g-oligo(L,L-lactide) copolymer (CLC) hydrogel for central nervous system tissue engineering. The biomechanical properties of the CLC hydrogel were characterized and its biocompatibility was assessed with neural progenitor cells obtained from two different sources: H9-derived neural stem cells (H9D-NSCs) and directly reprogrammed neural precursor cells (drNPCs). Our study found that the optically transparent CLC hydrogel possessed biomechanical characteristics suitable for culturing human neural stem/precursor cells and was noncytotoxic. When seeded on films prepared from CLC copolymer hydrogel, both H9D-NSC and drNPC adhered well, expanded and exhibited signs of spontaneous differentiation. While H9D-NSC mainly preserved multipotency as shown by a high proportion of Nestin+ and Sox2+ cells and a comparatively lower expression of the neuronal markers ßIII-tubulin and MAP2, drNPCs, obtained by direct reprogramming, differentiated more extensively along the neuronal lineage. Our study indicates that the CLC hydrogel may be considered as a substrate for tissue-engineered constructs, applicable for therapy of neurodegenerative diseases. Impact statement We synthetized a chitosan-g-oligo(L,L-lactide) hydrogel that sustained multipotency of embryonic-derived neural stem cells (NSCs) and supported differentiation of directly reprogrammed NSC predominantly along the neuronal lineage. The hydrogel exhibited no cytotoxicity in vitro, both in extraction and contact cytotoxicity tests. When seeded on the hydrogel, both types of NSCs adhered well, expanded, and exhibited signs of spontaneous differentiation. The biomechanical properties of the hydrogel were similar to that of human spinal cord with incised pia mater. These data pave the way for further investigations of the hydrogel toward its applicability in central nervous system tissue engineering.

Solvent-free synthesis and characterization of allyl chitosan derivatives.

The solvent-free synthesis of allyl-substituted chitosan derivatives through reactive co-extrusion of chitosan powder with allyl bromide at shear deformation was performed. For the structural characterization, FTIR and NMR methods were employed. The results were confirmed by chemical analysis. The total content of allyl substituents from 5 to 50 per 100 chitosan units as a function of the component ratio in the reactive mixtures was revealed. Carrying out the reaction without any additives leads to the selective formation of N-alkylated derivatives, whereas in the presence of alkali the ethers of chitosan were preferentially formed. The results suggest that the proposed approach allows significantly higher yield of products to be obtained at high process speeds and significantly lower reagent consumption as compared with the liquid-phase synthesis in organic medium. The synthesized unsaturated derivatives are promising photosensitive components for use in laser stereolithography for fabrication of three-dimensional biocompatible structures with well-defined architectonics.