Polysaccharides

Although diglycidyl ethers of glycols (DEs)—FDA-approved reagents for biomedical applications—were considered unsuitable for the fabrication of chitosan (CH) hydrogels and cryogels, we have recently shown that CH cross-linking with DEs is possible, but its efficiency depends on the nature of the acid used to dissolve chitosan and pH. To elucidate the origin of the low efficiency of chitosan interactions with DEs in acetic acid solutions, we have put forward two hypotheses: (i) DEs are consumed in a side reaction with acetic acid; (ii) DE chain length strongly affects the probability of cross-linking. We then verified them using FT-IR spectroscopy, rheological measurements, and uniaxial compression tests. The formation of esters in acetic acid solutions was confirmed for ethylene glycol diglycidyl ether (EGDE) and poly(ethylene glycol) diglycidyl ether (PEGDE). By the 7th day of gelation at pH 5.5, the G’_HCl/G’_HAc ratio was 5.1 and 1.5 for EGDE and PEGDE, respectively, indicating that the loss of cross-linking efficiency in acetic acid solution was less pronounced for the long-chain cross-linker. Under conditions of cryotropic gelation, only weak cryogels were obtained from acetic acid solutions at a DE:CH molar ratio of 1:1, while stable cryogels were fabricated at a molar ratio of 1:20 from HCl solutions. Full article

We cross-linked unfractionated heparin (H) using epichlorohydrin (E), in the absence or presence of imidazole (I), using various ratios of H, E, and I substances. The objectives and goals were to use the reaction for the preparation of medical materials suitable for blood sample applications. Nuclear magnetic resonance indicated the involvement of an H-end sequence [H-(1→4)-β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl-α-Ser] in the linkage with the 2-hydroxypropyl bridge. The yields of the individual experiments were found to increase in the following ratios: 1H/1E/3I (24%) < 1H/1E/2I (32%) < 1H/3E (42%) < 1H/1E/1I (46%) < 1H/2E (64%) < 1H/1E (77%). According to size-exclusion chromatography with multiple-angle light scattering (SEC-MALS) analysis, the mass at the peak increased in the following order: H (9292 g/mol) < 1H/1E (9294 g/mol) < 1H/2E (9326 g/mol) < 1H/3E (9708 g/mol) < 1H/1E/2I (11,212 g/mol) < 1H/1E/3I (12,301 g/mol) < 1H/1E/1I (13,800 g/mol) and in the reverse order with the increase in amount of epichlorohydrin and imidazole, i.e., 1H/1E > 1H/2E > 1H/3E and 1H/1E/1I > 1H/1E/2I > 1H/1E/3I. X-ray diffraction revealed that all prepared films were amorphous. An evaluation of the surface morphology using atomic force microscopy (AFM) confirmed a relatively low films roughness (~0.9–3.6 nm). The surface reduced elastic modulus, determined by the PeakForce quantitative nanomechanical mapping (PF-QNM) technique, was found to increase by up to ~63% for films cross-linked with E in the absence of I when compared with the results for the H substrate. A negligible change in modulus was, however, observed for films cross-linked in the presence of I, or was even reduced by ~15% (1H/1E/3I) compared to that for the H substrate. This could be explained by the parallel cross-linking of H only with E within its serine end unit and in competition with only one nitrogen of I. According to the highest yield (77%) of 1H/1E, the preferred product is the following: H-(1→4)-β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl-α-Ser-CH₂-CH(OH)-CH₂-OH. For the 1H/1E/1I (46% yield), 1H/1E/2I (32%), and 1H/1E/3I (24%) products, the cross-linked motif was the same, and the difference represented the surplus amount of the imidazolium cation ionically bound to the heparin anionic groups. Full article

Numerous bacterial species can both suppress plant pathogens and promote plant growth. By combining these bacteria with stabilizing substances, we can develop biological products with an extended shelf life, contributing to sustainable agriculture. Bacillus subtilis is one such bacterial species, possessing traits that enhance plant growth and offer effective protection, making it suitable for various applications. In this study, we successfully incorporated B. subtilis into hybrid materials composed of poly(3-hydroxybutyrate) (PHB) fibers coated with chitosan film. The polymer carrier not only supports the normal growth of the bioagent but also preserves its viability during long-term storage. For that reason, the impact of chitosan molecular weight on the dynamic viscosity of the solutions used for film formation, as well as the resulting film’s morphology, mechanical properties, and quantity of incorporated B. subtilis, along with their growth dynamics was investigated. SEM was used to examine the morphology of B. subtilis, electrospun PHB, and PHB mats coated with chitosan/B. subtilis. The results from mechanical tests demonstrate that chitosan film formation enhanced the tensile strength of the tested materials. Microbiological tests confirmed that the bacteria incorporated into the hybrid materials grow normally. The conducted viability tests demonstrate that the bacteria incorporated within the electrospun materials remained viable both after incorporation and following 90 days of storage. Moreover, the prepared biohybrid materials effectively inhibited the growth of the plant pathogenic strain Alternaria. Thus, the study provides more efficient and sustainable agricultural solutions by reducing reliance on synthetic materials and enhancing environmental compatibility through the development of advanced biomaterials capable of delivering active biocontrol agents. Full article

The increasing demand for sustainable materials has propelled research into polysaccharide modifications for various applications, particularly in active packaging. This review aims to explore the incorporation of bioactive compounds such as polyphenols into polysaccharides, focusing on chemical modification through free radical grafting techniques. The methods examined include enzymatic, physical, and chemical grafting techniques, highlighting their effectiveness in enhancing the properties of polysaccharide-based films. Recent studies have demonstrated that free radical grafting can significantly improve the mechanical, barrier, and antimicrobial properties of these films, extending their applicability in the food and pharmaceutical industries. However, challenges such as the stability of polyphenols and the understanding of grafting mechanisms remain critical areas for further investigation. This review discusses these advancements and outlines future research directions, emphasizing the potential of polysaccharide modifications to create innovative materials that meet the evolving needs of consumers and industries alike. Full article

The increasing production of plastics, driven by modern societal development, has resulted in a significant rise in plastic waste, which poses serious environmental concerns due to its lengthy degradation times. The growing issue of single-use plastics (SUPs), such as packaging for food items and disposable utensils, has led to their reduction and potential future prohibition in the European Union. Cellulose, a natural biopolymer sourced from nature, has been proposed as a viable alternative to SUPs because it degrades without toxicity. However, its limited barrier properties against water and grease have restricted its effectiveness as a substitute. This study focuses on developing an environmentally friendly alternative to SUPs by combining cellulose with acetylated starch and incorporating inorganic fillers like kaolin and talc. These fillers enhance the material’s barrier properties and reduce production costs. The results indicate that the addition of kaolin significantly lowers moisture absorption and water vapor permeability, while a mixture of kaolin and talc provides superior grease resistance. Additionally, incorporating D-sorbitol as a plasticizer improves the mechanical properties of the coated sheets, preventing cracking and enhancing strength. Overall, these coatings offer a promising alternative for packaging applications, such as for sugar, candies, or chocolate. Full article

Polysaccharide-functionalized gold nanoparticles (Au NPs) exhibit a promising application in biomedical fields due to their excellent stability and functional properties. The Au NPs from Auricularia auricula polysaccharide (AAP) were successfully synthesized using a straightforward method. By controlling the mass fraction of AAP, pH, reaction temperature, reaction time, and concentration of gold precursor, the highly dispersed spherical AAP-functionalized Au NPs (AAP-Au NPs) were prepared. The Fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS) indicated that the synthesis mechanism of AAP-Au NPs was as follows: the molecular chain of AAP undergoes a glycosidic bond breakage to expose the reduction terminus in the presence of gold precursor, which reduced Au(III) to Au(0), and itself was oxidized to carboxylate compounds for maintaining the stability of AAP-Au NPs. Additionally, based on the electrostatic interactions and steric forces, as-prepared AAP-Au NPs exhibit excellent stability at various pH (5–11), temperature (25–60 °C), 5 mmol/L glutathione, and 0.1 mol/L Na⁺ and K⁺ solutions. Furthermore, AAP-Au NPs retained the ability to scavenge DDPH and ABTS radicals, which is expected to expand the application of Au NPs in biomedical fields. Full article

Chitosan is a biopolymer with a wide range of applications. It typically requires depolymerization to achieve a desired molecular weight for specific uses. This study investigated the potential for depolymerizing chitosan by thermal shock and grinding to produce nanochitosan. A series of thermal shock cycles combined with grinding were performed to assess the influence of drying temperature, residence time, and number of thermal cycles on the molecular weight, particle size, and crystallinity of chitosan. The thermal shock reduced the molecular weight and particle size of chitosan within the first hour of treatment, with optimal conditions achieved at a drying temperature of 90 °C and residence time inside the oven of 5 min. These conditions resulted in a molecular weight of 15.0 kDa with an average diameter of 136 nm. Thermal shock can be considered an effective method for chitosan depolymerization with grinding serving to standardize the particle size. This optimized process offers promising applications where low-molecular-weight chitosan is required, including biomedical, agricultural, and food industries, as well as the potential for reducing time and energy consumption. Full article

Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning electron microscopy (SEM) were used to study the effects of heat treatments and water removal by freeze-drying after different time intervals (6, 12, 24, 48, and 72 h) on the molecular structure of potato tubers. SEM images show structural differences between raw (RP), microwaved (MP), and boiled potato (BP). MP showed a cracked structure. BP was able to re-associate into a granule-like structure after 6 h of freeze-dying, whereas RP had dried granules within a porous matrix after 24 h of freeze-drying. These results are consistent with the moisture content and FTIR results for MP and BP, which demonstrated dried spectra after 6 h of freeze-drying and relatively coincided with RP results after 24 h of freeze-drying. Additionally, three types of hydrogen bonds have been characterized between water and starch, and the prevalence of water very weakly bound to starch has also been detected. The relative crystallinity (RC) was increased by thermal treatment, whereby microwaving recorded the highest value. A comparison of the FTIR and XRD results indicated that freeze-drying treatment overcomes heat effects to generate an integral starch molecule. Full article

Hyaluronic acid (HA) plays important roles in tissue hydration and the transport of fluid and solutes through the interstitium. Hydroxyethyl starch (HES) solution is a synthetic colloid solution used during surgery. As HES leaks into the interstitium under inflammatory conditions during surgery, the effects of HES on HA’s structure and distribution are of clinical relevance. To examine these under fluid shear stress, dynamic shear moduli of 0.1% sodium hyaluronic acid (NaHA) solution with or without HES during shear stress loading were measured using a rotational rheometer for 8 h. The loss shear modulus of NaHA in 0.15 M NaCl solution decreased over time by 30% relative to that before shear stress loading. The presence of 1% and 2% HES reduced the decrease in loss shear modulus of NaHA solution to 20% and 4%, respectively. To investigate the convective transport of 0.1% fluorescein-labeled hyaluronic acid (FHA) by infusion of 0.15 M NaCl or HES solution, the absorbance of FHA in a UV flow cell was continuously measured. HES solution of 0.5% increased transported FHA quantities by 120% compared to 0.15 M NaCl solution. HES-induced attenuation of shear-induced distortion of HA and acceleration of convective transport of HA should be considered during surgery. Full article

RNA interference (RNAi) is a promising approach for gene therapy in cancers, but it requires carriers to protect and deliver therapeutic small interfering RNA (siRNA) molecules to cancerous cells. Starch-based carriers, such as quaternized starch (Q-Starch), have been shown to be biocompatible and are able to form nanocomplexes with siRNA, but significant electrostatic interactions between the carrier and siRNA prevent its release at the target site. In this study, we aim to characterize the effects of the degree of substitution (DS) and molecular weight (Mw) of Q-Starch on the gene silencing capabilities of the Q-Starch/siRNA transfection system. We show that reducing the DS reduces the electrostatic interactions between Q-Starch and siRNA, which now decomplex at more physiologically relevant conditions, but also affects additional parameters such as complex size while mostly maintaining cellular uptake capabilities. Notably, reducing the DS renders Q-Starch more susceptible to enzymatic degradation by α-amylase during the initial Q-Starch pretreatment. Enzymatic cleavage leads to a reduction in the Mw of Q-Starch, resulting in a 25% enhancement in its transfection capabilities. This study provides a better understanding of the effects of the DS and Mw on the polysaccharide-based siRNA delivery system and indicates that the polysaccharide Mw may be the key factor in determining the transfection efficacy of this system. Full article

This research work focuses on the development of an environmentally friendly wound dressing using natural polymers. The inclusion of cannabis in these hydrogels stems from its innovative potential in medicine, particularly for wound healing and pain relief. The hydrogels were prepared by a simple methodology using natural polysaccharides, and cannabis extract through electrostatic interactions and crosslinking with sodium tripolyphosphate (TPP). Several tests were carried out to analyze the morphological, physical, thermal, mechanical, barrier, and antimicrobial properties of these hydrogels. Different types of hydrogels were synthesized including chitosan- gum arabic hydrogel (ChiGA), hydrogel loaded with cannabis extract (ChiGACann), hydrogel crosslinked with TPP (ChiGATPP), and ChiGACann crosslinked with TPP (ChiGACannTPP). The impact of both cannabis extract and TPP crosslinking on the properties of chitosan hydrogels was investigated. The significant swelling capacity measured to the hydrogels, with ChiGACann exhibiting a 250–350% in physiological conditions, making them suitable for wound dressing applications due to their exudate absorption capacity. Antimicrobial activity evaluation demonstrated that the hydrogels acted as barriers against different microorganisms, with Gram-positive bacteria being more sensitive than Gram-negative bacteria. Mechanical testing showed improved mechanical properties in the presence of cannabis extract and TPP crosslinking (20–30 kPa of compression modulus). In conclusion, these results highlight the application of ChiGACann hydrogels as promising materials for manufacturing wound dressings. Full article

This study determined the optimal production of furfural (FuR) from liquid hydrolysate xylan liquor obtained through a two-stage pretreatment process using NaOH for de-ashing and EtOH for the delignification of raw rice husk (RH). The de-ashing pretreatment was conducted at 150 °C, with 6.0% (w/v) NaOH and a reaction time of 40 min. The optimal conditions for delignification pretreatment, performed using an organosolv fractionation method with EtOH, were a reaction temperature of 150 °C, 60% (v/v) EtOH, 0.25% (w/v) H₂SO₄, and a reaction time of 90 min. Through a two-stage pretreatment process, a liquid hydrolysate in the form of xylan liquor was obtained, which was subjected to an acid catalytic conversion process to produce FuR. The process conditions were varied, with reaction temperatures of 130–170 °C, H₂SO₄ catalyst concentrations of 1.0–3.0 wt.%, and reaction times of 0–90 min. The Response Surface Methodology tool was used to identify the optimal FuR yield from xylan liquor. Ultimately, the optimal process conditions for the acid catalytic conversion were found to be a substrate-to-catalyst ratio of 2:8, a reaction temperature of 168.9 °C, a catalyst concentration of 1.9 wt.%, and a reaction time of 41.24 min, achieving an FuR yield of 67.31%. Full article

The chitinous skeleton of the marine demosponge Ianthella basta exhibits a unique network-like 3D architecture, excellent capillary properties, and chemical inertness, making it highly suitable for interdisciplinary research, especially in biomedical applications. This study investigates the potential of renewable I. basta chitinous scaffolds for drug delivery and wound dressing. The scaffolds, characterized by a microtubular structure, were impregnated with selected commercially available antiseptics, including solutions with hydrophilic and hydrophobic properties. Evaluations against selected clinical strains of bacteria, as well as fungi, demonstrated significant zones of growth inhibition with antiseptics such as brilliant green, gentian violet, decamethoxine, and polyhexanide. Notably, the antibacterial properties of these antiseptic-treated chitin matrices persisted for over 72 h, effectively inhibiting microbial growth in fresh cultures. These findings highlight the considerable potential of I. basta chitin scaffolds as sustainable, innovative biomaterials for controlled drug release and wound dressing applications. Full article

Annona muricata is a fruit species belonging to the Annonaceae family, which is native to the warmer tropical areas of North and South America. A large amount of discarded residue from A. muricata is of interest for obtaining new industrial inputs. To propose the applications of the biopolymer from A. muricata residues (Biop_AmRs), this study aimed to characterize this input chemically and functionally, as well as to evaluate its potential for hemocompatibility and cytotoxicity activity in vitro. Biop_AmRs is an anionic heteropolysaccharide composed of glucose, arabinose, xylose, galactose, mannose, uronic acid, and proteins. This biopolymer exhibited a semicrystalline structure and good thermal stability. Biop_AmRs exhibited excellent water holding capacity, emulsifying properties, and mucoadhesiviness and demonstrated hemocompatibility and cytocompatibility on the L929 cell line. These results indicate possible applications for this biopolymer as a potential environmentally friendly raw material in the food, pharmaceutical, biomedical, and cosmetic industries. Full article

The paper presents the production of thermoplastic starch (TPS) mixtures using potato starch and two types of plasticizers: glycerol and sorbitol. The effects of plasticizers, citric acid, organically modified montmorillonite clay nanofiller (OMMT) and an additive based on ultrahigh molecular weight siloxane polymer on the structure and physical–mechanical and thermal properties of TPS samples were analysed. Starch mixtures plasticized with glycerol were obtained, where the starch/glycerol mass ratio was 70:30, as well as starch mixtures plasticized with glycerol and sorbitol, with a starch/glycerol/sorbitol mass ratio of 60:20:20. The starch gelatinization process to obtain TPS was carried out in a Brabender Plasti-Corder internal mixer at 120 °C, with a mixing speed of 30–80 rpm, for 10 min. The obtained results indicate that by adding 2% (weight percentage) of citric acid to the TPS mixtures, there is an improvement in the physical–mechanical properties, as well as structural changes that can indicate both cross-linking reactions by esterification in stages and depolymerisation reactions. The sample of TPS plasticized with glycerol, which contains OMMT, shows an increase in tensile strength by 34.4%, compared to the control sample. Full article

Kefiran is a heteropolysaccharide that is considered a postbiotic and is obtained by kefir grains fermented in cow’s milk, while little is known about the donkey milk (DM) variety. Postbiotics are recognised as having important human health benefits that are very similar to probiotics but without the negative effects associated with their ingestion. Donkey is a monogastric animal, as are humans, and when used as an alternative food for infants who suffer from cow milk protein allergies, DM could therefore display more biocompatibility. In this study, the DM kefiran was extracted by ultrasound from kefir grains cultured in donkey milk and fully characterized for its structural and physicochemical properties by Fourier-transform infrared spectroscopy (FT-IR), High-Performance Liquid Chromatography- Refractive Index (HPLC-RI), Scanning electron microscope (SEM), Differential Scanning Calorimeters (DSC) and rheological analyses. In addition, tests were conducted on keratinocytes cell lines and human red blood cells to assess the nontoxicity and haemolysis degree of the polymer. The extraction yield of the DM kefiran was 6.5 ± 0.15%. The FT-IR analysis confirmed the structure of the polysaccharide by showing that the stretching of the C-O-C and C-O bonds in the ring, which formed two bands at 1157 and 1071 cm⁻¹, respectively, and the anomeric band at 896 cm⁻¹ indicates the β configuration and vibrational modes of glucose and galactose. Results were confirmed by HPLC-RI analysis indicating that the ratio glucose/galactose was 1:0.87. Furthermore, the SEM analysis showed a porous and homogeneous structure. The rheological analysis confirmed the pseudoplastic nature of the polymer, while the DSC analysis highlighted excellent thermal resistance (324 °C). Finally, DM kefiran was revealed to have biologically acceptable toxicity, showing a haemolytic activity of less than 2% when using fresh human red blood cells and showing no cytotoxicity on human keratinocytes. Therefore, kefiran obtained by DM shows an excellent biocompatibility, establishing it as a promising polymer for bioengineering human tissue for regenerative applications. Full article

Fenugreek (Trigonella foenum-graecum L.) is an annual, dicotyledonous medicinal plant which belongs to the Leguminosae family, and its leaves and seeds are widely used and cultivated throughout the world. Their widespread utilization is attributed to the great variety of primary and secondary metabolites they contain, such as flavonoids, alkaloids, steroidal saponins, tannins, as well as carbohydrates, in particular galactomannan, which is the focus of the current study. The presence of an equal number of galactose and mannose residues (Gal/Man ratio of 1:1) prevents the formation of hydrogen bonds between the mannose ones. This determines the good solubility of fenugreek galactomannan in cold water, even at low concentrations. The water solubility would be significantly better than that of carob and even slightly higher than that of guar gum, precisely due to their structural characteristics, which contribute to their possible advantages. Moreover, it is a good alternative as an excipient for the development of pharmaceutical dosage forms, as well as in the preparation of food products, affecting not only their structure but also their shelf life. Furthermore, it has promising applications not only in the fields of medicine and pharmaceutics but also offers environmental benefits. All of the above-mentioned factors are of high interest and qualify fenugreek galactomannan as a versatile polysaccharide, which is the reason for summarizing its benefits in this review. Full article

Cellulose obtained from oat hulls by bleaching with peracetic acid was modified, employing an ultrasound method that resulted in an esterification reaction with different vegetable oils (soybean, sunflower, and coconut) to produce modified cellulose (MC) with increased hydrophobicity. MC samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, scanning electron microscopy, and their wettability and oil and water absorption capacities. FTIR indicated that the reaction occurred with all oils, which was observed by forming a new band associated with ester carbonyl groups at 1747 cm⁻¹. The modification did not affect the crystalline structure or surface morphology of the cellulose. MC samples modified with all oil sources showed a 6 to 9-fold decrease in water absorption capacity, a 3-fold increase in oil absorption capacity, and a higher affinity for nonpolar solvents. The modified samples adsorbed lower amounts of water at a slower rate. Different oil sources did not affect the main properties of MC. The ultrasonication-assisted process was not only effective in modifying cellulose by esterification with vegetable oils but was also an eco-friendly and simple strategy that does not require toxic reagents, providing reassurance of its sustainability. Full article

Protein hydrolysates containing bioactive peptides have emerged as therapeutic agents. However, these peptides may lose this bioactivity under gastrointestinal conditions. Encapsulation in edible biopolymers is a solution to this problem. Protein hydrolysates with ACE-I inhibitory activity, obtained previously, were encapsulated. A 1% solution of the biopolymers alginate (AG) and pectin (PC) in various ratios was prepared. The beads formed were evaluated in both wet and dry states for size, roundness, thermal gravimetric analysis (TGA), encapsulation efficiency, and ACE-I inhibitory activity. Selected samples underwent in vitro digestion, after which peptide release and ACE-I inhibitory activity were determined. Size analysis revealed that increasing the PC content increased the bead size, with 100% PC beads showing total deformation and reduced roundness. TGA indicated that wet beads had lower thermal stability compared to dry beads. The highest encapsulation efficiency (95.57% ± 0.49) was observed with 100% AG beads. The 75% AG 25% PC beads exhibited the highest ACE-I inhibitory activity (97.97% ± 1.01). Encapsulated protein hydrolysates retained their ACE-I inhibitory activity after simulated digestion, whereas non-encapsulated hydrolysates lost their bioactivity. Encapsulation of amaranth protein hydrolysates with AG and PC thus preserves antihypertensive activity even after in vitro digestion. Full article