Chitosan oligosaccharide (COS): An overview

Hydrogel Based on Bletilla Striata Polysaccharide for Sustained Sodium Danshensu Release for Wound Healing

Bletilla striata polysaccharide (BSP) is effective at healing wounds and has important application value in the research and development of biomedical materials. In this study, BSP, chitosan, and sodium β-glycerophosphate were used to generate a complex hydrogel with a very small pore size of 10-30 μm without the use of cross-linking agents. By improving the cross-linking density, the mechanical property defects caused by excessive BSP dissolution were overcome without affecting its physiological activity. Moreover, the small molecule Danshen sodium (SDSS) was loaded into the three-dimensional network of this hydrogel to form a hydrogel drug carrier system. SDSS could be released in the long term, and the total amount released after 53 h was 96.26 ± 2.57%. The BSP hydrogel had good water absorption (169.47 ± 4.54%) and bonding properties. In vitro studies confirmed that it has a good antibacterial performance and biocompatibility and the ability to promote cell proliferation (>200%) and migration. Molecular experiments confirmed that the hydrogel promotes collagen expression. In vivo experiments using a mouse wound healing model confirmed that the hydrogel has an excellent ability to promote wound healing, particularly during the first 7 days of the wound. The wound healing rate of the hydrogel group was higher than that of the blank group by 27.61% (p < 0.05), and the effect of the hydrogel to promote wound healing was confirmed by wound tissue staining.

Ursodeoxycholic acid grafted chitosan oligosaccharide self-assembled micelles with enhanced oral absorption and antidiabetic effect of oleanolic acid

Oleanolic acid (OA) is a food-derived bioactive component with antidiabetic activity, but its water solubility and oral bioavailability are notably restricted. In this study, to overcome these limitations, ursodeoxycholic acid-modified chitosan oligosaccharide (UCOS) was synthesized to encapsulate OA in self-assembled nanomicelles (UCOS-OA). The encapsulation efficiency and drug loading of UCOS-OA were 86 % and 11 %, respectively. UCOS-OA exhibited enhanced gastrointestinal stability and prolonged intestinal retention time when compared with free OA, resulting in a 10.6-fold increase in oral bioavailability. The enhanced antidiabetic activity of UCOS-OA was confirmed in the type 2 diabetes mellitus mice model, as it significantly improved glycolipid metabolism disorders and mitigated liver injury. Furthermore, UCOS-OA ameliorated the dysbiosis of gut microbiota and fecal metabolites. In conclusion, UCOS serves as an effective polymeric carrier for encapsulating OA, thereby improving its bioavailability and antidiabetic activity. This work provides valuable insights for the advancement of oral delivery systems for bioactive compounds.

Prospects and applications of efficient physical field processing technologies for polysaccharide extraction and quality improvement in edible mushrooms: A systematic review

Edible mushroom-derived polysaccharides (EMPs) have been widely used in foods, medicine, and cosmetics due to theirs' diverse and versatile biological activities. Currently, many conventional extraction methods for extracting EMPs are struggling to meet the growing demand, and the produced EMPs with poor quality and low bioactivity. Novel physical field (e.g., acoustic, electromagnetic, electrical, and mechanical field) processing technologies not only overcome the shortcomings of conventional extraction methods, but also improve the structural feature, bioactivity, and solution behavior of EMPs. Moreover, physical field-assisted techniques can induce the degradation or modification of EMPs, thereby effectively altering the physicochemical properties and structural features of EMPs to improve their bioactivities or processing properties. Therefore, a comprehensive review of physical field processing technologies such as ultrasound, high pressure, pulsed electric field, and microwave for extracting and modifying EMPs in recent years, is presented. In addition, recent advances in physical field-assisted extraction/degradation techniques for EMPs, as well as their mechanisms of action and synergistic effects, are discussed and summarized. In summary, this review provides a theoretical basis and practical guidance for the physical field processing technology in improving the extraction yield and quality of EMPs, as well as large-scale industrial production.

An anti-inflammatory and anti-fibrotic Janus hydrogel for preventing postoperative peritoneal adhesion

Postoperative peritoneal adhesion (PPA) is pathological tissue hyperplasia between surgical wounds and nearby organs. Currently, traditional double-sided bioadhesives are limited in preventing PPA due to the indiscriminate adhesive properties and the poor interaction with wet tissues. Herein, we developed a Janus hydrogel, named PAA-Cos, by using the polycationic carbohydrate polymer of chitooligosaccharide (Cos) and the polyanionic polymer of polyacrylic acid (PAA). The adhesive layer of Janus hydrogels could adhere to wet tissue tightly due to surfaces composed of carboxyls, and the positively charged biomaterial (Cos) neutralized carboxyls on one side of PAA hydrogel to form Janus hydrogels. Moreover, PAA-Cos can further load with ligustrazine hydrochloride (Ligu), a pharmaceutical compound with anti-inflammatory and anti-fibrotic effects, finally obtaining PAA-Cos@Ligu. After the application of PAA-Cos@Ligu on the surgical trauma, the bottom surface can adhere to wet tissues robustly to restore the wound, while the top surface acts as a physical barrier with antiadhesive effects to avoid PPA. PAA-Cos@Ligu also exhibited anti-inflammatory effects by promoting M2 macrophage polarization, inhibiting the myofibroblast-like differentiation of peritoneal mesothelial cells, and blocking the TGF-β/Smad2/3 signaling pathway to hinder collagen deposition. Our findings suggest that PAA-Cos@Ligu has great potential as an anti-adhesion candidate with biocompatibility and ease of preparation.

Development of supercritical technology to obtain improved functional dietary fiber for the valorization of broccoli by-product

BACKGROUND

This research aimed to enhance the functional value of dietary fiber from broccoli leaves using supercritical fluid technology. By optimizing pressure, temperature, and time parameters through response surface methodology, the study sought to improve the bioactive properties of the fiber and develop a predictive model for its chemical composition and functional properties.

RESULTS

Structural analysis indicated that modified samples had a higher concentration of oligosaccharides than control samples did, with significant increases in galacturonic acid and neutral sugars after supercritical fluid technology treatment, highlighting enhanced pectin release due to cell wall degradation. Functional properties, such as water solubility, glucose absorption capacity, and antioxidant activity, improved significantly under optimized conditions (191 bar, 40 °C, 1 h). Multivariate analysis confirmed the effectiveness of supercritical fluid technology in enhancing the dietary fiber properties, achieving a global desirability value of 0.805.

CONCLUSION

These results underscore the potential of supercritical technology for valorizing broccoli leaf by-products, enhancing their health-promoting characteristics and functional applications in the food industry. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Chitooligosaccharide enhances plant resistance to P. nicotianae via sugar homeostasis and microorganism assembly

Phytophthora nicotianae is a highly destructive soil-borne plant pathogen that leads to significant economic losses in agriculture. Chitooligosaccharides (COS) are popular biostimulant which can promote plant growth and responses to biotic and abiotic stresses. However, the role of COS in resisting the black-shank disease (BSD, caused by P. nicotianae) through regulating plant root exudates and rhizosphere microecology remains unclear. An integrative analysis, based on the transcriptome analysis, root exudate metabolome, and biochemical tests, revealed the secretion of more sugar-related differential metabolites and differential gene expressions expressed under COS treatment during the disease resistance response. Furthermore, increased accumulation of trehalose and trehalose 6-phosphate as well as increased activity of trehalose 6-phosphate synthase was observed under COS treatment after inoculation with P. nicotianae. Additionally, sucrose and glucose, which positively regulate resistance to plant diseases, also exhibited elevated levels. Beneficial microorganisms, such as Bacillus were enriched in the rhizosphere soil during COS treatment. The isolated Bacillus velezensis T-2 strain exerted inhibitory activity on P. nicotianae, which was enhanced by the presence of trehalose. This multi-omics study of transcriptome, metabolome, and microbiomics revealed that COS enhances resistance to tobacco BSD by regulating sugar homeostasis and recruiting beneficial microorganisms.

Chito-oligosaccharide impairs the proliferation, invasion and migration of pancreatic cancer cells

BACKGROUND

Chito-oligosaccharide (COS) is a low molecular weight polymer obtained by degrading chitosan through special enzymatic technology, with good water solubility and high biological activity. It is also the only positively charged cationic basic amino oligosaccharide in nature. Studies have confirmed that COS has antitumour effect, but research on its effect on pancreatic cancer (PC) remains limited and unclear. This study aimed to explore the effects of COS on PC cells (PANC-1 and MIAPaCa-2).

METHOD

We used different concentrations of COS to treat PC cells and conducted Cell Counting Kit-8, wound-healing, and transwell assays to evaluate the proliferation, invasion, and migration ability of PC cells, respectively. Western blot was conducted to assess the expression levels of epithelial-mesenchymal transition (EMT) related markers.

RESULT

The proliferation, invasion, and migration ability of PC cells (PANC-1 and MIAPaCa-2) gradually decreased in a manner dependent on COS concentration. COS at 10 mg/mL exerted the strongest inhibitory effect on the two PC cell lines. At 10 mg/mL, the proliferative activity was 60.61% ± 5.25% and 64.02% ± 4.96%, respectively; the invasive ability was (18.67 ± 4.416) and (31.33 ± 3.162), respectively; and the cell-migration ability was 26.83% ± 0.442% and 17.66% ± 0.647%, respectively. The expression levels of N-cadherin and vimentin were significantly downregulated in PANC-1 cells (0.198 ± 0.047 and 0.225 ± 0.038, respectively) and MIAPaCa-2 cells (0.214 ± 0.094 and 0.214 ± 0.094, respectively) at 10 mg/mL, respectively. Conversely, E-cadherin was upregulated (0.460 ± 0.037 and 0.491 ± 0.047, respectively). Compared with control group, the differences were statistically significant.

CONCLUSION

The upregulation of E-cadherin and the downregulation of vimentin and N-cadherin suggested that the specific mechanism of COS in PC may be related to EMT. This study provided a new direction for PC treatment.

Construction of Chitosan Oligosaccharide-Coated Nanostructured Lipid Carriers for the Sustained Release of Strontium Ranelate

BACKGROUND

Strontium ranelate (SR) is an effective bone regeneration drug; however, its low bioavailability and strong hydrophilicity cause a strong cytotoxicity, venous thrombosis, and allergic reactions when administered in its free form. This study aims to enhance the SR bioavailability by utilizing nanostructured lipid carriers (NLC) as a drug delivery system (DDS).

METHODS

To improve the drug delivery efficiency and sustained release of the NLC, their surfaces were coated with chitosan oligosaccharide (COS), a natural polymer. The synthesis of COS-NLC was confirmed by measuring particle size and zeta potential, while surface morphology was evaluated using atomic force microscopy (AFM). SR loading efficiencies and release profiles were analyzed via reversed-phase high-performance liquid chromatography (RP-HPLC), and cytotoxicity was evaluated in mouse fibroblast L929 cells.

RESULTS

Particle characterization indicated that the COS coating slightly increased the particle size (i.e., from 128.99 ± 2.77 to 131.46 ± 2.13 nm) and zeta potential (i.e., from - 13.94 ± 0.49 to - 6.58 ± 0.32 mV) of the NLC. The COS-NLC exhibited a high SR-loading efficiency of ~ 86.31 ± 3.28%. An in vitro release test demonstrated an improved sustained release tendency of SR from the COS-NLC compared to that from the uncoated NLC. In cytotoxicity assays using L929 cells, the COS coating reduced the cytotoxicity of the formulated DDS, and the SR-COS-NLC exhibited a 1.4-fold higher cell regeneration effect than SR alone.

CONCLUSION

These findings suggest that the developed COS-NLC serve as an effective and biocompatible DDS platform for the delivery of poorly bioavailable drugs.

Preparation, characterization and antibacterial investigation of water-soluble curcumin-chitooligosaccharide complexes

Curcumin has a wide range of application prospects, with various bioactivities in the food industry and in the biomedical field. However, curcumin has poor water solubility and is sensitive to pH, light and temperature. In this study, curcumin-chitooligosaccharide (CUR-COS) complexes were prepared via mechanochemical methods, and the CUR-COS complex was more soluble after freeze-drying (up to 862-fold greater than that of curcumin). The complex was characterized by SEM, XRD, FT-IR and thermal analysis, and its stability against pH, light and thermal treatment was evaluated. COSs could serve as carriers for curcumin delivery. Additionally, the antibacterial activity of the formed complex was determined. As a result, CUR-COS exhibited significantly better water solubility, enhanced stability, and stronger antibacterial properties than did pure CUR, offering a promising pathway for the extensive application of lipophilic natural products in foods, especially water-based products.

Genipin crosslinked sodium caseinate-chitosan oligosaccharide nanoparticles for optimizing β-carotene stability and bioavailability

In this study, genipin served as crosslinker to combine sodium caseinate (SC) and chitosan oligosaccharide (COS), aiming to improve the physicochemical properties and encapsulation efficiency of SC in delivering hydrophobic nutritional factors. The genipin crosslinked complex of SC and COS (GSCC) was characterized by circular dichroism spectrum and infrared spectrum analyses. Nanoparticles produced from GSCC (GSCCNP) exhibited a superior hydrophilicity compared to those derived from SC (SCNP). GSCCNP significantly augmented the encapsulation efficacy and photostability of β-carotene. β-Carotene encapsulated within GSCCNP (βC-GSCCNP) exhibited remarkable in vitro sustained release characteristics and heightened bioavailability. In addition, βC-GSCCNP showed significant in vitro anti-inflammatory activity. These findings indicated that genipin crosslinking COS-modified SC could construct a nano-delivery system to enhance the stability and bioavailability of insoluble nutritional factors, thereby presenting promising applications for hydrophobic nutrients in the development of functional foods and beverages.

Natural Feed Supplements From Crustacean Processing Side Streams for Improved Growth of Finfishes and Crustaceans: A Review

Natural feed additives of plant/animal/microbial origin are researched as supplements in aquaculture to improve the properties of feed, minimize the usage of chemical alternatives, reduce food safety risks and ensure sustainability to combat global food and nutritional security. Side streams generated during shellfish processing possess valuable ingredients: protein, lipids, carotenoids, minerals and chitins. Considering the current trend of organic farming and antibiotic-free fish and shellfish, crustacean processing side streams and their derivatives seem promising and emerging resources as natural additives/supplements for formulating high-quality feeds with superior benefits. Lower concentrations of chitin and chitosan in diets are reported to stimulate the growth of shellfish and finfish under controlled conditions. Oligomers of chitosan and nano-chitosan are also the other potential derivatives as natural supplements in feed for better growth performance of aquaculture varieties. This review focuses on the significance of crustacean processing side streams and their derivatives, especially shrimp head meal, chitin, chitosan and chitosan oligosaccharides as potential natural additives in aquafeeds for promoting the growth performance of cultured fin fishes and shell fishes. Utilization in aquafeeds and the development of natural value-added supplements from crustacean processing side streams, especially shrimp head and shell leftover, offer an answer to the negative environmental impact due to its dumping; reduce the dependency on food fish for fish meal production & fishmeal for aquafeeds; solution to maintain the economic viability of the fish farmers & industry as well as to ensure the supply of safer and healthy aquatic foods to meet the objectives of sustainable development goals.

A low chemical consumption cationization and salt-free dyeing process for cotton fabrics by reusing polyallylamine modification bath

Cationic polymers have been used in the cationization of cotton fabrics for salt-free dyeing, but commonly used polymers are limited by their high molecular weight and low adsorption efficiency, leading to high dosage or complex modification conditions. In this study, polyallylamine with low molecular weight was found to be an efficient cationic agent for cotton modification and the modified fabrics can be salt-free dyed with different kinds of reactive dyes after the optimization of the modification process. Furthermore, the modification bath was reused by replenishing a small amount of cationic agent and adjusting the pH to the original level. The results showed that all the salt-free dyed cotton fabrics had excellent performance when the fabrics were modified with a 2 g L-1 polyallylamine solution at pH 12 for 1 h. During five consecutive bath reusing cycles, the elemental nitrogen content, zeta potential, and salt-free dyeing performance of the modified cotton fabrics were relatively stable, all the uptakes of C.I. reactive red 24 were >75 %, and all the K/S values of the dyed fabrics were higher than 11, much greater than that of conventional dyeing (about 6). In addition, compared with the conventional dyeing process and the salt-free dyeing with the bath-unreused route, the bath-reused and salt-free dyeing process reduces by 98.36 % and 62.31 % chemicals consumption per kilogram of dyed cotton fabric, respectively. This work provides a low-pollution process for salt-free dyeing of cationic cotton fabrics and provides a reference for improving the utilization efficiency of the cationic agent.

Mining, Identification, and Fermentation Optimization of Chitin Deacetylase from a Novel Strain Enterobacter sp. ZCDA27

Chitin, a natural organic compound with content slightly lower than cellulose, is also known for chitosan, a substance derived from chitin through deacetylation. In this experiment, preliminary screening was conducted using the plate discoloration circle method, leading to the selection of a high-yield CDA-producing strain from 28 candidates through rescreening. Morphological characteristics and 16S rDNA sequence analysis revealed 99.93% homology with Enterobacter sichuanensis strain N24, thus naming this strain Enterobacter strain ZCDA27. Initial fermentation of the strain yielded CDA activity of 9.29 U/mL. Single-factor optimization was then performed, followed by a PB test to screen for significant factors affecting enzyme production. The response surface method was used to further optimize the fermentation conditions. The optimal fermentation conditions for the carbon source, nitrogen source, metal ion, fermentation temperature, time, liquid volume, and initial pH were explored. Significant factors affecting enzyme production, including MgSO4, initial medium pH, and fructose levels, were identified using the PB test. Finally, the fermentation conditions of ZCDA27 were optimized using the Box-Behnken design combined with RSM, which comprised fructose at 1.020%, magnesium sulfate at 0.016%, and peptone at 1%. The fermentation conditions included a temperature of 37, initial pH of 7.1, rotation speed of 140 × g, fermentation time of 28 h, inoculation amount of 2%, and liquid volume of 40%. Under these conditions, the enzyme activity of ZCDA27 reached 14.52 U/mL, a 1.6-fold increase from the pre-optimization levels. In summary, this study provides an experimental foundation for further development and application of Enterobacter spp. ZCDA27 CDA.

The blood-brain barriers: novel nanocarriers for central nervous system diseases

The central nervous system (CNS) diseases are major contributors to death and disability worldwide. However, the blood-brain barrier (BBB) often prevents drugs intended for CNS diseases from effectively crossing into the brain parenchyma to deliver their therapeutic effects. The blood-brain barrier is a semi-permeable barrier with high selectivity. The BBB primarily manages the transport of substances between the blood and the CNS. To enhance drug delivery for CNS disease treatment, various brain-based drug delivery strategies overcoming the BBB have been developed. Among them, nanoparticles (NPs) have been emphasized due to their multiple excellent properties. This review starts with an overview of the BBB's anatomical structure and physiological roles, and then explores the mechanisms, both endogenous and exogenous, that facilitate the NP passage across the BBB. The text also delves into how nanoparticles' shape, charge, size, and surface ligands affect their ability to cross the BBB and offers an overview of different nanoparticle classifications. This review concludes with an examination of the current challenges in utilizing nanomaterials for brain drug delivery and discusses corresponding directions for solutions. This review aims to propose innovative diagnostic and therapeutic approaches for CNS diseases and enhance drug design for more effective delivery across the BBB.

Chitosan-based structures for skin repair: A literature review

The use of chitosan in technological and biomedical applications has gained significant relevance due to its functional properties. Among its biological activities, its hemostatic, analgesic, antibacterial and anti-inflammatory activities make this natural biopolymer one of the most promising in the development of structures for skin repair. Its application and effects can be optimized by exploring efficient structuring techniques. In this context, this review is based on scientific evidence reported in the last decade regarding the development and use of chitosan-based structures in the skin repair process to show the most common structuring methods, the main mechanisms of action of chitosan, and its potential applications in skin repair processes. Additionally, this article brings a compilation of scientific and commercial works on the use of chitosan-based structures, in addition to vitro and/or in vivo results.

Chitosan oligosaccharides ameliorates maternal diabetes-induced embryonic neural tube defects via inhibitting excessive pyroptosis of neuroepithelial cells

Maternal diabetes significantly induces embryonic neural tube defects (NTDs). Thus, it is urgent need to further investigate the regulatory mechanism and therapeutic strategy for maternal diabetes-induced embryonic NTDs. Pyroptosis is a novel mode of programmed cell death. The role of pyroptosis on the maternal diabetes-induced embryonic NTDs is still unclear. Chitosan oligosaccharides (COSs) is a kind of natural polysaccharide with anti-inflammatory and anti-oxidant bioactivities, and its role on NTDs formation is poorly understood. Here, we hypothesized that excessive pyroptosis is another important mechanism for diabetes-induced NTDs formation, and COSs can exert its anti-inflammatory and antioxidant activities to alleviate maternal diabetes-mediated embryonic neuroepithelial cells pyroptosis and NTDs formation. Firstly, we confirmed that maternal diabetes significantly induces the embryonic NTDs formation (13.2% of NTDs rate). More interestingly, the mechansim study found that maternal diabetes significantly triggers the elevated pyroptosis level in embryos. And VX765, a pyroptosis inhibitor, significantly ameliorated the diabetes-induced embryonic NTDs (1.9% NTDs). Additionally, COSs treatment significantly reduced the maternal diabetes-associated the embryonic NTDs formation with 2.6% NTDs rate. Mechanistic studies further demonstrated that COSs significantly inhibits maternal diabetes-induced elevated inflammatory response and oxidative stress in embryos, and subsequently ameliorates the pyroptotic level of embryonic neuroepithelial cells through inhibiting TXNIP-NLRP3 complex formation. In a conclusion, pyroptosis is a another key caused event for maternal diabetes-induced embryonic NTDs. COSs exerts its antioxidant effect to inhibit the pyroptosis of neuroepithelial cells and consequently alleviates maternal diabetes-induced embryonic NTDs.

A review on the biological activities and the nutraceutical potential of chitooligosaccharides

Chitooligosaccharides (CHOS) or chitosan oligosaccharides (COS) are oligomers mainly composed of d-glucosamine (GlcN) units and structured in a positively charged, basic, amino molecule obtained from the degradation of chitin/chitosan through physical, chemical, or enzymatic methods. CHOS display physicochemical properties attractive to applications from the food to the biomedical field, such as non-toxicity to humans, high water solubility, low viscosity, biocompatibility, and biodegradability. These properties also allow CHOS to exert important biological activities, for example, antioxidant, antimicrobial, anti-inflammatory, immunomodulatory, antitumor, and hypocholesterolemic ones, besides to exhibit applications in food systems, technological, and nutraceutical potential. Therefore, this study summarized the synthesis and chemical structure, biological functions, and mechanisms of action of CHOS; with this, we aimed to contribute to the knowledge about the application of CHOS from the food to the biomedical industries.

Enhancing Aqueous Solubility and Anticancer Efficacy of Oligochitosan-Folate-Cisplatin Conjugates through Oleic Acid Grafting for Targeted Nanomedicine Development

Oligochitosan is an anticancer water-soluble biomaterial. Conjugating cisplatin (anticancer drug) and folic acid (targeting ligand) with oligochitosan reduces its aqueous solubility, thus requiring excessive drug dose to be biologically active and organic instead of aqueous processing into nanomedicine. Covalent grafting of oleic acid onto oligochitosan-folate-cisplatin conjugate is envisaged to promote aqueous solubility via reducing interchain interaction, but it is challenging where multiple functional moieties are covalently attached onto a short oligomer (<5 kDa). This study produced oligochitosan-oleate-folate-cisplatin conjugate dissolvable in aqueous media pH 3-7, which represents common processing pH in drug vehicle development and tumor microenvironmental pHs. Oligochitosan-oleate conjugation was effected through O-acylation to provide amino groups of oligochitosan for folate and cisplatin grafting. Oligochitosan-folate-cisplatin conjugate was poorly soluble in aqueous and organic media. A degree of oleic acid substitution (DS) < 10% conferred aqueous solubility beyond which became less soluble due to hydrophobicity rise. Oligochitosan-oleate-folate-cisplatin conjugate with 4.51 ± 0.32% DS, 8.50 ± 0.57% folate content, and 0.94 ± 0.80% cisplatin content was dissolvable in aqueous media pH 3.3-7, conferring processing safety with improved cancer cytotoxicity in the nanoparticulate form at the acidic tumor microenvironment.

Chitooligosaccharides suppress airway inflammation, fibrosis, and mucus hypersecretion in a house dust mite-induced allergy model

Background

Respiratory allergy is a serious respiratory disorder characterized by inflammation, mucus hypersecretion, and airway tissue sclerosis. Disruption of the T helper 1 (Th1) and T helper 2 (Th2) immune systems by stimuli induced by house dust mites (HDM) and fine particulate matter leads to the secretion of various inflammatory cytokines, resulting in immune respiratory diseases characterized by airway inflammation. Chitooligosaccharides (COS) are known for their antioxidant and anti-inflammatory properties.

Methods

Human airway epithelial cells (BEAS-2B) were cultured in DMEM/F12 medium containing COS at concentrations of 25-100 µg/ml for 24 h. No intracellular toxicity was observed up to 1,000 µg/ml. Cell experiments were conducted at COS concentrations below 100 µg/ml, while animal experiments were performed at concentrations below 100 mg/kg body weight for 4 weeks. Samples of right lung tissue obtained from the experimental animals were used for gene and protein expression analysis, whereas samples of contralateral lung tissue were used for immunohistochemical analysis.

Results

COS regulated Th1 immunity by inhibiting major cytokines, including inflammatory tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), in BEAS-2B cells. In the HDM-induced allergic respiratory model, COS suppressed the infiltration of inflammatory cells around the airways and inhibited the mRNA expression of Th1 immune cytokines in lung tissues, while also reducing the expression of nuclear factor kappa B (NF-κB)-related proteins. Furthermore, the results confirmed the suppression of the levels of immunoglobulin E (IgE) in the blood secreted by mast cells activated by HDM, which led to a reduction in allergic mucus hypersecretion and airway sclerosis.

Conclusion

In summary, COS are thought to improve airway resistance by alleviating inflammatory allergic respiratory diseases caused by HDM and are regarded as substances that regulate the balance of the Th1 and Th2 immune systems in epithelial cells affected by mucus hypersecretion.

Iota-Carrageenan/Chitosan Nanoparticles via Coacervation: Achieving Stability for Tiny Particles

This study investigated the influence of parameters such as pH condition, polyelectrolyte concentration, polymer ratio, and order of addition of the commercial polyelectrolytes chitosan and iota-carrageenan (ι-carrageenan) on the formation of polymeric nanoparticles in suspension (coacervates). A preliminary purification step of the polymers was essential for obtaining stable nanoparticles with small sizes as impurities, particularly metal ions that interfere with complexation, are removed by dialysis. Microparticles (13.5 μm in dry diameter) are obtained when aliquots of chitosan solution are poured into the ι-carrageenan solution. In general, an excess of chitosan results in the formation of agglomerated particles. The addition of an aliquot of ι-carrageenan solution (30 mL at 0.6 mg/mL and pH 4.0) to the chitosan solution (6.0 mL at 0.3 mg/mL and pH 4.0) leads to dispersed nanoparticles with a hydrodynamic radius of 278 ± 5 nm, a zeta potential of -31 ± 3 mV, and an average dry diameter of 45 ± 11 nm. The hydrodynamic radius increases as the pH rises. The partial deprotonation of ι-carrageenan chains enhances the interaction with water molecules, causing the particles to swell. These findings contribute to the fundamental understanding of polyelectrolyte complexation processes in aqueous suspension and provide insights for developing stable nanomaterials for potential practical applications.

Sustained release of nano-encapsulated glimepiride drug with chitosan nanoparticles: A novel approach to control type 2 diabetes in streptozotocin-induced Wistar albino rats

The objective of the present study was to encapsulate the effective antidiabetic glimepiride (GLM) drug with biodegradable chitosan nanoparticles (CS NPs) in order to reduce the risk of side effects, regulate and improve alternatives to therapy for people with type 2 Diabetes mellitus. The characterizations of the encapsulated EGLM-CS NPs were published in a previous paper. In continuation of the past study, here we report the in vitro and in vivo activities of EGLM-CS NPs in streptozotocin-induced diabetes Wistar albino rats orally treated for 28 days. Based on our results, the in vitro 3 T3-L1 cell lines observed that the highest concentration of 500 μg/mL exhibited 91.48 % cell viability after 24 h of treatment. The in vivo results of the EGLM-CS NPs treated rats group showed gradual control of the blood glucose level at 90 and 120 min compared to other groups because the drug showed a sustained release mechanism. A significant difference was observed in serum lipid profiles between diabetic treated and control rats. It is believed that the CS NPs served as a carrier system for the GLM drug, protected it from degradation, and enhanced its solubility as well as bioavailability. After 28 days of treatment, all the animal groups organs (pancreas, liver, and kidney) were dissected for histopathological analysis. The EGLM-CS NPs treated group displayed regeneration cells of the islets of Langerhans in the pancreas and normal cellular size with hyperplasia. The therapeutic potential was observed by the liver and kidney from rats reveals few tubule necrosis, improved bioavailability as compared to pure GLM drug treated rats. Hence, our formulated NPs are safe, no toxic effect on the vital organs, which will be helpful to improve the lives of diabetic patients and contribute to the overall health of the individuals.

Chitosan-Based Hydrogels as Antibacterial/Antioxidant/Anti-Inflammation Multifunctional Dressings for Chronic Wound Healing

Due to repeated microbial infection, persistent inflammation, excessive oxidative stress, and cell dysfunction, chronic wounds are difficult to heal, posing a serious threat to public health. Therefore, developing multifunctional wound dressings that can regulate the complex microenvironment of chronic wounds and enhance cellular function holds great significance. Recently, chitosan has emerged as a promising biopolymer for wound healing due to its excellent biocompatibility, biodegradability, and versatile bioactivity. The aim of this review is to provide a comprehensive understanding of the mechanisms of delayed chronic wound healing and discuss the healing-promoting properties of chitosan and its derivatives, such as good biocompatibility, antibacterial activity, hemostatic capacity, and the ability to promote tissue regeneration. On this basis, the potential applications of chitosan-based hydrogels are summarized in chronic wound healing, including providing a suitable microenvironment, eliminating bacterial infections, promoting hemostasis, inhibiting chronic inflammation, alleviating oxidative stress, and promoting tissue regeneration. In addition, the concerns and perspectives for the clinical application of chitosan-based hydrogels are also discussed.

Marine polysaccharides for antibiofilm application: A focus on biomedical fields

Microbial pathogens such as bacteria and fungi form biofilms, which represent substantial hurdles in treating human illness owing to their adaptive resistance mechanism to conventional antibiotics. Biofilm may cause persistent infection in a variety of bodily areas, including wounds, oral cavity, and vaginal canal. Using invasive devices such as implants and catheters contributes significantly to developing healthcare-associated infections because they offer an ideal surface for biofilm formation. Marine organisms produce a variety of polysaccharides, which have recently attracted worldwide attention due to their biochemical features, various applications, and advantageous properties such as bioactivity, biodegradability, and biocompatibility. Because of their antimicrobial and antibiofilm features, several polysaccharides such as chitosan, fucoidan, carrageenan, alginate, and hyaluronic acid have been used to treat infected wounds as well as ophthalmic, oral, and vaginal infections. In addition, marine polysaccharides are currently employed as coatings on medical devices and implant materials, alone or in combination with other bioactive substances or nanomaterials, to protect the materials' undertones from microbial contamination. This review discussed the recent advancements in marine polysaccharides and their derivatives as a therapeutic potential against biofilm-associated diseases. The potential obstacles in the scalability of their production, clinical translation, and/or regulatory hurdles have also been discussed.

Extracellular matrix-based biomaterials in burn wound repair: A promising therapeutic strategy

Burns are common traumatic injuries affecting many people worldwide. Development of specialized burn units, advances in acute care modalities, and burn prevention programs have successfully reduced the mortality rate of severe burns. Autologous skin grafting has been considered as the gold standard for wound coverage after the removal of burned skin. For full-thickness burns of a larger scale, however, the autograft donor site may be quickly exhausted, so that alternative skin coverage is necessary. Although rapid progress has been made in the development of skin substitutes for burn wounds during the last decade, no skin substitute has fulfilled the criteria as a perfect replacement for the damaged skin. Extracellular matrix (ECM) derived components have emerged as a source for the engineering of biomaterials capable of inducing desirable cell-specific responses and one of the most promising biomaterials for burn wound healing. Among these, acellular dermal matrix, small intestinal submucosa, and amniotic membrane have been applied to treat burn wounds with acceptable outcomes. This review has explored the use of biomaterials derived from naturally occurring ECM and their derivatives for approaches aiming to promote burn wound healing, and summarized the ECM-based wound dressings products applicable in burn wound and postburn scar contracture to date.

Chitooligosaccharides improves intestinal mucosal immunity and intestinal microbiota in blue foxes

Objective

Gut health is critical to the health of the host. This study was conducted to investigate the effects of Chitooligosaccharides (COS) on intestinal morphology, intestinal barrier, intestinal immunity and cecum microbiota of blue foxes.

Methods

Seventy-two 125-day-old blue foxes were randomly divided into basal diet (BD) group, 200 ppm COS1 (1.5 kDa) group and 200 ppm COS2 (3 kDa) group for 8 weeks.

Results

We elucidated that dietary COS1 supplementation promoted the development of intestinal villus morphology in blue foxes. Importantly, COS1 increased the number of goblet cells in duodenum, jejunum and ileum by 27.71%, 23.67%, 14.97% and S-IgA secretion in duodenum, jejunum and ileum by 71.59% and 38.56%, and up-regulate the expression of Occludin and ZO-1 by 50.18% and 148.62%, respectively. Moreover, COS1 promoted the pro-inflammatory and anti-inflammatory balance of small intestinal mucosa, and increased the diversity of cecum microbiota of blue foxes, especially Lactobacillus_agilis and Lactobacillus_murinus, and up-regulated the signaling pathways related to polysaccharide decomposition and utilization.

Conclusion

Here, we present dietary COS1 (1.5 kDa) can promote intestinal villus development, enhance intestinal barrier function, regulate intestinal immune balance and cecum microbiota homeostasis.

Dynamic covalent bonds enabled recyclable chitosan oligosaccharide-based wood adhesive with high adhesion and anti-mildew performances

Biomass wood adhesives have emerged as a promising alternative to traditional synthetic resins due to their ability to address issues related to formaldehyde pollution and reliance on petrochemical resources. However, these adhesives are generally not recyclable and require high curing temperatures. Herein, a novel eco-friendly, strong, and recyclable chitosan oligosaccharide (CS)-based wood adhesive named CS-PB was developed using CS, lignin-derived 3,4-dihydroxybenzaldehyde, and 1,4-phenylenediboronic acid. The cohesive strength and recyclability of the adhesive were significantly enhanced by the dynamic borate ester and imine networks formed through catalyst-free covalent cross-linking. The adhesive exhibited a maximum bonding strength of 5.60 MPa, surpassing many synthetic and biomass adhesives. Moreover, the recycled adhesive retained 88 % of its original strength. Even under extreme conditions such as 100 °C, -196 °C the CS-PB adhesive can still maintain high bonding strength. Notably, the CS-PB adhesive demonstrated low-temperature curing properties, achieving a high bonding strength of 5.21 MPa when cured at 90 °C, since imine bonds can be formed under mild conditions. Furthermore, the adhesive displayed excellent mildew resistance attributed to the synergistic effects of amino, boronic acid, and benzene rings. The proposed straightforward design strategy provides valuable insights for constructing high-strength and recyclable biomass adhesives.

Isolation of a novel Bacillus strain with industrial potential of producing alkaline chitosanase

A novel Bacillus strain, designated as HZ20-1, was discovered. This strain can produce naturally alkaline chitosanase without induction. Genomic analysis revealed that this chitosanase belongs to glycoside hydrolase family 8. When colloidal chitosan is used as a substrate, the maximum enzyme activity of 2.39 ± 0.03 U/mL is observed at a pH range of 8.5-9. This alkaline enzyme holds advantages over common acidic enzymes in various fields such as medicine, the environment, and daily chemical products, and thus has great market value. Moreover, as the chitosanase is a constitutive enzyme, there is no need for substrate induction. This can simplify fermentation equipment and reduce production cost. Additionally, in a preliminary study, we found that this strain can also degrade chitin and chitosan derivatives. After analysis, it was discovered that it has genes in glycoside hydrolase families 18 and 23. By controlling the enzymatic hydrolysis time, it is possible to produce products with different molecular weights, including N-acetylglucosamine, glucosamine, chito-oligosaccharides, and chitin oligosaccharides. Consequently, Bacillus sp. HZ20-1 is considered to have great potential for future industrial production of enzymes and oligosaccharides.

Vibrio cholerae virulence is blocked by chitosan oligosaccharide-mediated inhibition of ChsR activity

Vibrio cholerae causes cholera, an important cause of death worldwide. A fuller understanding of how virulence is regulated offers the potential for developing virulence inhibitors, regarded as efficient therapeutic alternatives for cholera treatment. Here we show using competitive infections of wild-type and mutant bacteria that the regulator of chitosan utilization, ChsR, increases V. cholerae virulence in vivo. Mechanistically, RNA sequencing, chromatin immunoprecipitation with sequencing and molecular biology approaches revealed that ChsR directly upregulated the expression of the virulence regulator, TcpP, which promoted expression of the cholera toxin and the toxin co-regulated pilus, in response to low O2 levels in the small intestine. We also found that chitosan degradation products inhibit the ChsR-tcpP promoter interaction. Consistently, administration of chitosan oligosaccharide, particularly when delivered via sodium alginate microsphere carriers, reduced V. cholerae intestinal colonization and disease severity in mice by blocking the chsR-mediated pathway. These data reveal the potential of chitosan oligosaccharide as supplemental therapy for cholera treatment and prevention.

Chitinase and Deacetylase-Based Chitin-Degrading Bacteria: One-Pot Cascade Bioconversion of Chitin to Chitooligosaccharides

Cascade conversion of chitin into soluble and functional chitooligosaccharides has gained great attention. However, the biotransformation route is still limited to the low catalytic performances of chitin deacetylases (CDAs) and complicated procedures. In this study, a CDA from Arthrobacter sp. Jub115 (ArCDA) was identified and characterized, which showed a higher catalytic stability than the reported CDAs, with residual activity of 80.49%, 71.12%, and 56.09% after incubation at 30, 35, and 40 °C for 24 h, respectively. Additionally, ArCDA was identified to have a broad substrate spectrum toward β-chitin and N-acetyl chitooligosaccharides. Moreover, an engineered chitin-degrading bacteria (CDB) with cell-surface-displayed deacetylase ArCDA and chitinase SaChiB was constructed to simplify catalysis procedures, facilitating the chitobiose production of 294.30 ± 16.43 mg/L in 10 h. This study not only identified a CDA with the desirable catalytic performance but also provided a strategy for constructing CDB, facilitating the high-value utilization of chitin.

Biodegradation Study of Food Packaging Materials: Assessment of the Impact of the Use of Different Biopolymers and Soil Characteristics

In this article, the relationship between the properties of different membranes (agar, chitosan, and agar + chitosan) and biodegradability in natural and sterilized soil was investigated. The membranes under investigation exhibited variations in the biodegradation process, a phenomenon closely linked to both the soil microbiota composition and their water affinity. Higher solubility in water and greater swelling tendencies correlated with shorter initiation times for the biodegradation process in soil. Overall, all tested membranes began biodegradation within 14 days, as assessed through thickness and morphological analysis parameters, demonstrating a superior degradation rate compared to low-density polyethylene films.

Reactive oxygen species responsive chitooligosaccharides based nanoplatform for sonodynamic therapy in mammary cancer

Sonodynamic therapy (SDT) has been extensively studied as a new type of non-invasive treatment for mammary cancer. However, the poor water solubility and defective biocompatibility of sonosensitizers during SDT hinder the sonodynamic efficacy. Herein, a nanoplatform has been developed to achieve high efficient SDT against mammary cancer through the host-guest interaction of β-cyclodextrin/5-(4-hydroxyphenyl)-10,15,20-triphenylporphyrin (β-CD-TPP) and ferrocenecarboxylic acid/chitooligosaccharides (FC-COS). Moreover, the glucose oxidase (GOx) was loaded through electrostatic adsorption, which efficiently restricts the energy supply in tumor tissues, thus enhancing the therapeutic efficacy of SDT for tumors. Under optimal conditions, the entire system exhibited favorable water solubility, suitable particle size and viable biocompatibility. This facilitated the integration of the characteristics of starvation therapy and sonodynamic therapy, resulting in efficient inhibition of tumor growth with minimal side effects in vivo. This work may provide new insights into the application of natural oligosaccharides for construct multifunctional nanocarrier systems, which could optimize the design and development of sonodynamic therapy strategies and even combination therapy strategies.

Enhancing plant fiber antibacterial and antiviral performance through synergistic action of amino and sulfonic acid groups

As the most abundant renewable resource, cellulose fibers are potential candidates for use in health-protective clothing. Herein, we demonstrate a novel strategy for preparing cellulose fiber with prominent antibacterial and antiviral performance by the synergistic effect of amino groups and sulfonic acid groups. Specifically, guanylated chitosan oligosaccharide (GCOS) and N-sulfopropyl chitosan oligosaccharide (SCOS) were synthesized and chemically grafted onto cellulose fibers (CFs) to endow the fibers with antibacterial and antiviral properties. Moreover, a compounding strategy was applied to make the fibers with simultaneously high antibacterial and antiviral activity, especially in short contact time. The bacteriostatic rate (against S. aureus: 95.81 %, against E. coli: 92.07 %, 1 h) of the compounded fibers improved substantially when a few GCOS-CFs were mixed with SCOS-CFs; especially, it was much higher than both the individual GCOS-CFs and SCOS-CFs. By contrast, the improvement of the antiviral properties was less dramatic; however, even a few SCOS-CFs was mixed, the antiviral properties increased pronouncedly. Although the electrostatic interaction between SCOS and GCOS can make the SCOS-GCOS mixture lose some extent of antibacterial activity, the long chains of cellulose restrain the electrostatic interaction between sulfonic and amino groups, leading to their synergistic action and eventually superior antibacterial and antiviral effects.

Recent Progress in Enzymatic Preparation of Chitooligosaccharides with a Single Degree of Polymerization and Their Potential Applications in the Food Sector

Chitosan oligosaccharides (COS), derived from chitin, have garnered considerable attention owing to their diverse biological activities and potential applications. Previous investigations into the bioactivity of COS often encountered challenges, primarily stemming from the use of COS mixtures, making it difficult to discern specific effects linked to distinct degrees of polymerization (DP). Recent progress underscores the significant variation in the biological activities of COS corresponding to different DPs, prompting dedicated research towards synthesizing COS with well-defined polymerization. Among the available methods, enzymatic preparation stands out as a viable and environmentally friendly approach for COS synthesis. This article provides a comprehensive overview of emerging strategies for the enzymatic preparation of single COS, encompassing protein engineering, enzymatic membrane bioreactors, and transglycosylation reactions. Furthermore, the bioactivities of single COS, including anti-tumor, antioxidant, antibacterial, anti-inflammatory, and plant defense inducer properties, exhibit close associations with DP values. The potential applications of single COS, such as in functional food, food preservation, and crop planting, are also elucidated.

Coaxial nanofibrous aerogel featuring porous network-structured channels for ovarian cancer treatment by sustained release of chitosan oligosaccharide

Ovarian cancer, the deadliest gynecological malignancy, primarily treated with chemotherapy. However, systemic chemotherapy often leads to severe toxic side effects and chemoresistance. Drug-loaded aerogels have emerged as a promising method for drug delivery, as they can improve drug solubility and bioavailability, control drug release, and reduce drug distribution in non-targeted tissues, thereby minimizing side effects. In this research, chitosan oligosaccharide (COS)-loaded nanofibers composite chitosan (CS) aerogels (COS-NFs/CS) with a porous network structure were created using nanofiber recombination and freeze-drying techniques. The core layer of the aerogel has a COS loading rate of 60 %, enabling the COS-NFs/CS aerogel to significantly inhibit the migration and proliferation of ovarian cancer cells (resulting in a decrease in the survival rate of ovarian cancer cells to 33.70 % after 48 h). The coaxial fiber's unique shell-core structure and the aerogel's porous network structure enable the COS-NFs/CS aerogels to release COS steadily and slowly over 30 days, effectively reducing the initial burst release of COS. Additionally, the COS-NFs/CS aerogels exhibit good biocompatibility, degradability (only retaining 18.52 % of their weight after 6 weeks of implantation), and promote angiogenesis, thus promoting wound healing post-oophorectomy. In conclusion, COS-NFs/CS aerogels show great potential for application in the treatment of ovarian cancer.

Exploring the Potentials of Chitin and Chitosan-Based Bioinks for 3D-Printing of Flexible Electronics: The Future of Sustainable Bioelectronics

Chitin and chitosan-based bioink for 3D-printed flexible electronics have tremendous potential for innovation in healthcare, agriculture, the environment, and industry. This biomaterial is suitable for 3D printing because it is highly stretchable, super-flexible, affordable, ultrathin, and lightweight. Owing to its ease of use, on-demand manufacturing, accurate and regulated deposition, and versatility with flexible and soft functional materials, 3D printing has revolutionized free-form construction and end-user customization. This study examined the potential of employing chitin and chitosan-based bioinks to build 3D-printed flexible electronic devices and optimize bioink formulation, printing parameters, and postprocessing processes to improve mechanical and electrical properties. The exploration of 3D-printed chitin and chitosan-based flexible bioelectronics will open new avenues for new flexible materials for numerous industrial applications.

Methotrexate-Loaded Chitosan Oligosaccharide-ES2 for Targeted Cancer Therapy

Cancer presents a significant health threat, necessitating the development of more precise, efficient, and less damaging treatment approaches. To address this challenge, we employed the 1-ethyl-(3-dimethyl aminopropyl) carbodiimide/N-hydroxy succinimide (EDC/NHS) catalytic system and utilized quaternized chitosan oligosaccharide (HTCOSC) as a drug carrier to construct a nanoparticle delivery system termed HTCOSC-cRGD-ES2-MTX (CREM). This system specifically targets integrin αvβ3 on tumor cell surfaces and enables simultaneous loading of the antiangiogenic agent ES2 (IVRRADRAAVP) and the chemotherapy drug methotrexate (MTX). Due to its amphiphilic properties, CREM self-assembles into nanoparticles in aqueous solution, exhibiting an average diameter of 179.47 nm. Comparative studies demonstrated that CREM, in contrast to free ES2 and MTX-free nanoparticles (CRE), significantly suppressed the proliferation of EAhy926 endothelial cells and B16 melanoma cells in vitro, resulting in inhibition rates of 71.18 and 82.25%, respectively. Furthermore, CREM exhibited a hemolysis rate below 2%, indicating excellent in vitro antiangiogenic and antitumor activity as well as favorable blood compatibility. Additionally, both CRE and CREM demonstrated favorable tumor targeting capabilities through the specific binding action of cyclic RGD (cRGD) to integrin αvβ3. Further in vivo investigations revealed that CREM induced apoptosis in tumor cells via the mitochondrial apoptotic pathway and reduced the expression of angiogenic factors such as vascular endothelial growth factor (VEGF), thereby inhibiting tumor angiogenesis. This potent antitumor effect was evident through a tumor suppression rate of 80.19%. Importantly, histopathological staining (HE staining) demonstrated the absence of significant toxic side effects of CREM on various organs compared to MTX. In conclusion, the CREM nano drug delivery system synergistically enhances the therapeutic efficacy of antiangiogenic drugs and chemotherapeutic agents, thus offering a novel targeted approach for cancer treatment.

Physicochemical analysis of chitosan oligosaccharide revealed its usefulness in effective delivery of drugs

Chitosan oligosaccharides are biopolymers with a wide range of potential applications in various fields. This biopolymer is diverse and promising, and current research is investigating its capabilities for improved drug delivery. As chitosan oligosaccharide has the potential to be used as a drug delivery option, the purpose of this study was to examine its physicochemical characteristics and its potential for drug delivery. In this study, the pharmacokinetic properties of chitosan oligosaccharide were studied through Insilco investigation, which revealed that it is an extremely soluble and effective drug delivery candidate because it does not inhibit CYP isoenzymes and has a log Kp of -12.10 cm/s. It belongs to toxicity class 6 for acute oral toxicity, with an average similarity of 87.5% and a prediction accuracy of 70.97%. Additionally, XRD peak analysis revealed that the material was amorphous, as the peak appeared at 2θ = 24.62°, indicating the absence of well-defined crystalline areas. This characteristic makes the material more suitable for customization in many applications such as drug delivery and tissue engineering. FTIR, SEM, and TGA analysis were performed to gain a better understanding. These findings also emphasize the distinctive qualities and benefits of the oligosaccharides in this domain. Application of chitosan oligosaccharides in the development of efficient drug delivery systems. In the future, it would be more effective, targeted, and safe, with potent therapeutic efficacy for drug delivery.

Construction and characterization of Zn-WPH-COS complex nanoparticles with improved zinc bioavailability

Precipitation was an important obstacle to improving zinc's bioavailability. Therefore, zinc-whey protein hydrolysate-chitosan oligosaccharide (Zn-WPH-COS) complexes (167 nm) were prepared by linking Zn-WPH (zinc: 18.4%) with COS (1:1, 2 h) to enhance zinc's bioaccessibility. Fourier-transform infrared showed Zn-WPH formed with zinc replaced hydrogen (from 3274 to 3279 cm-1) and reacted with COO- (C-N: from 1394 to 1402 cm-1), a new peak at 1025 cm-1 proved COS can be successful cross-linked (Zn-WPH-COS). Fluorescence spectra showed zinc and COS reduced WPH hydrophobicity (28.0 and 39.0%, respectively). Circular dichroism showed zinc decreased WPH α-helix (from 13.7 to 11.5%), in contrast with COS to Zn-WPH. Zinc solubility and dialyzability were increased (64.5/ 54.2% vs 50.2/ 41.2% vs 29.5/ 21.7%) in Zn-WPH-COS, compared with Zn-WPH and ZnSO4·7H2O, respectively, due to the smallest size (167 nm) and COS protection on Zn-WPH (gastric digestion). These results indicate Zn-WPH-COS could significantly improve the digestion and absorption of zinc.

Applications of polysaccharides in enzyme-triggered oral colon-specific drug delivery systems: A review

Enzyme-triggered oral colon-specific drug delivery system (EtOCDDS1) can withstand the harsh stomach and small intestine environments, releasing encapsulated drugs selectively in the colon in response to colonic microflora, exerting local or systematic therapeutic effects. EtOCDDS boasts high colon targetability, enhanced drug bioavailability, and reduced systemic side effects. Polysaccharides are extensively used in enzyme-triggered oral colon-specific drug delivery systems, and its colon targetability has been widely confirmed, as their properties meet the demand of EtOCDDS. Polysaccharides, known for their high safety and excellent biocompatibility, feature modifiable structures. Some remain undigested in the stomach and small intestine, whether in their natural state or after modifications, and are exclusively broken down by colon-resident microbiota. Such characteristics make them ideal materials for EtOCDDS. This article reviews the design principles of EtOCDDS as well as commonly used polysaccharides and their characteristics, modifications, applications and specific mechanism for colon targeting. The article concludes by summarizing the limitations and potential of ETOCDDS to stimulate the development of innovative design approaches.

Chitosanase-immobilized magnetite-agar gel particles as a highly stable and reusable biocatalyst for enhanced production of physiologically active chitosan oligosaccharides

A novel immobilized chitosanase was developed and utilized to produce chitosan oligosaccharides (COSs) via chitosan hydrolysis. Magnetite-agar gel particles (average particle diameter: 338 μm) were prepared by emulsifying an aqueous agar solution dispersing 200-nm magnetite particles with isooctane containing an emulsifier at 80 °C, followed by cooling the emulsified mixture. The chitosanase from Bacillus pumilus was immobilized on the magnetite-agar gel particles chemically activated by introducing glyoxyl groups with high immobilization yields (>80%), and the observed specific activity of the immobilized chitosanase was 16% of that of the free enzyme. This immobilized chitosanase could be rapidly recovered from aqueous solutions by applying magnetic force. The thermal stability of the immobilized chitosanase improved remarkably compared with that of free chitosanase: the deactivation rate constants at 35 °C of the free and immobilized enzymes were 8.1 × 10-5 and 3.9 × 10-8 s-1, respectively. This immobilized chitosanase could be reused for chitosan hydrolysis at 75 °C and pH 5.6, and 80% of its initial activity was maintained even after 10 cycles of use. COSs with a degree of polymerization (DP) of 2-7 were obtained using this immobilized chitosanase, and the product content of physiologically active COSs (DP ≥ 5) reached approximately 50%.

Comparison of the protective effects of chitosan oligosaccharides and chitin oligosaccharide on apoptosis, inflammation and oxidative stress

Chitin degradation products, especially chitosan oligosaccharides (COSs), are highly valued in various industrial fields, such as food, medicine, cosmetics and agriculture, for their rich resources and high cost-effectiveness. However, little is known about the impact of acetylation on COS cellular bioactivity. The present study aimed to compare the differential effects of COS and highly N-acetylated COS (NACOS), known as chitin oligosaccharide, on H2O2-induced cell stress. MTT assay showed that pretreatment with NACOS and COS markedly inhibited H2O2-induced RAW264.7 cell death in a concentration-dependent manner. Flow cytometry indicated that NACOS and COS exerted an anti-apoptosis effect on H2O2-induced oxidative damage in RAW264.7 cells. NACOS and COS treatment ameliorated H2O2-induced RAW264.7 cell cycle arrest. Western blotting revealed that the anti-oxidation effects of NACOS and COS were mediated by suppressing expression of proteins involved in H2O2-induced apoptosis, including Bax, Bcl-2 and cleaved PARP. Furthermore, the antagonist effects of NACOS were greater than those of COS, suggesting that acetylation was essential for the protective effects of COS.

A new strain of Rhodococcus indonesiensis T22.7.1T and its functional potential for deacetylation of chitin and chitooligsaccharides

Introduction

Chitin, abundant in marine environments, presents significant challenges in terms of transformation and utilization. A strain, T22.7.1T, with notable chitin deacetylation capabilities, was isolated from the rhizosphere of Acanthus ebracteatus in the North Sea of China. Comparative 16S rDNA sequence analysis showed that the new isolate had the highest sequence similarity (99.79%) with Rhodococcus indonesiensis CSLK01-03T, followed by R. ruber DSM 43338T, R. electrodiphilus JC435T, and R. aetherivorans 10bc312T (98.97%, 98.81%, and 98.83%, respectively). Subsequent genome sequencing and phylogenetic analysis confirmed that strain T22.7.1T belongs to the R. indonesiensis species. However, additional taxonomic characterization identified strain T22.7.1T as a novel type strain of R. indonesiensis distinct from CSLK01-03T.

Methods

This study refines the taxonomic description of R. indonesiensis and investigates its application in converting chitin into chitosan. The chitin deacetylase (RiCDA) activity of strain T22.7.1T was optimized, and the enzyme was isolated and purified from the fermentation products.

Results

Through optimization, the RiCDA activity of strain T22.7.1T reached 287.02 U/mL, which is 34.88 times greater than the original enzyme's activity (8.0 U/mL). The natural CDA enzyme was purified with a purification factor of 31.83, and the specific activity of the enzyme solution reached 1200.33 U/mg. RiCDA exhibited good pH and temperature adaptability and stability, along with a wide range of substrate adaptabilities, effectively deacetylating chitin, chitooligosaccharides, N-acetylglucosamine, and other substrates.

Discussion

Product analysis revealed that RiCDA treatment increased the deacetylation degree (DD) of natural chitin to 83%, surpassing that of commercial chitosan. Therefore, RiCDA demonstrates significant potential as an efficient deacetylation tool for natural chitin and chitooligosaccharides, highlighting its applicability in the biorefining of natural polysaccharides.

Albumin Nanoparticle-Based Drug Delivery Systems

Nanoparticle-based systems are extensively investigated for drug delivery. Among others, with superior biocompatibility and enhanced targeting capacity, albumin appears to be a promising carrier for drug delivery. Albumin nanoparticles are highly favored in many disease therapies, as they have the proper chemical groups for modification, cell-binding sites for cell adhesion, and affinity to protein drugs for nanocomplex generation. Herein, this review summarizes the recent fabrication techniques, modification strategies, and application of albumin nanoparticles. We first discuss various albumin nanoparticle fabrication methods, from both pros and cons. Then, we provide a comprehensive introduction to the modification section, including organic albumin nanoparticles, metal albumin nanoparticles, inorganic albumin nanoparticles, and albumin nanoparticle-based hybrids. We finally bring further perspectives on albumin nanoparticles used for various critical diseases.

Chitosan and Chitooligosaccharides: Antifungal Potential and Structural Insights

Chitosan is a cationic polysaccharide derived from chitin deacetylation. This polysaccharide and its oligosaccharides have many biological activities and can be used in several fields due to their favorable characteristics, such as biodegradability, biocompatibility, and nontoxicity. This review aims to explore the antifungal potential of chitosan and chitooligosaccharides along with the conditions used for the activity and mechanisms of action they use to kill fungal cells. The sources, chemical properties, and applications of chitosan and chitooligosaccharides are discussed in this review. It also addresses the threat fungi pose to human health and crop production and how these saccharides have proven to be effective against these microorganisms. The cellular processes triggered by chitosan and chitooligosaccharides in fungal cells, and prospects for their use as potential antifungal agents are also examined.

Sulfonamide modified chitosan oligosaccharide with high nematicidal activity against Meloidogyne incognita

Chitosan oligosaccharide (COS) modification is a feasible way to develop novel green nematicides. This study involved the synthesis of various COS sulfonamide derivatives via hydroxylated protection and deprotection, which were then characterized using NMR, FTIR, MS, elemental analysis, XRD, and TG/DTG. In vitro experiments found that COS-alkyl sulfonamide derivatives (S6 and S11-S13) exhibited high mortality (>98 % at 1 mg/mL) against Meloidogyne incognita second-instar larvaes (J2s) among the derivatives. S6 can cause vacuole-like structures in the middle and tail regions of the nematode body and effectively inhibit egg hatching. In vivo tests have found that S6 has well control effects and low plant toxicity. Additionally, the structure-activity studies revealed that S6 with a high degree of substitution, a low molecular weight, and a sulfonyl bond on the amino group of the COS backbone exhibited increased nematicidal activity. The sulfonamide group is a potential active group for developing COS-based nematicides.

Fucoidan alleviates the inhibition of protein digestion by chitosan and its oligosaccharides

Chitosan (CTS) and chitosan oligosaccharides (COS) have been widely applied in food industry due to their bioactivities and functions. However, CTS and COS with positive charges could interact with proteins, such as whey protein isolate (WPI), influencing their digestion. Interaction among CTS/COS, FUC, and WPI/enzymes was studied by spectroscopy, chromatography, and chemical methods in order to reveal the role of FUC in relieving the inhibition of protein digestibility by CTS/COS and demonstrate the action mechanisms. As shown by the results, the addition of FUC increased degree of hydrolysis (DH) and free protein in the mixture of CTS and WPI to 3.1-fold and 1.8-fold, respectively, while raise DH value and free protein in the mixture of COS and WPI to 6.7-fold and 1.2-fold, respectively. The interaction between amino, carboxyl, sulfate, and hydroxyl groups from carbohydrates and protein could be observed, and notably, FUC could interact with CTS/COS preferentially to prevent CTS/COS from combining with WPI. In addition, the addition of FUC could also relieve the combination of CTS to trypsin, increasing the fluorescence intensity and concentration of trypsin by 83.3 % and 4.8 %, respectively. Thus, the present study demonstrated that FUC could alleviate the inhibitory effect of CTS/COS on protein digestion.

In Vitro Evaluation of Chito-Oligosaccharides on Disappearance Rate of Nutrients, Rumen Fermentation Parameters, and Micro-Flora of Beef Cattle

The study aimed to investigate the effect of dietary chitosan oligosaccharides (COS) meal levels on the nutrient disappearance rate, rumen fermentation, and microflora of beef cattle in vitro. A total of 24 fermentation tanks were randomly divided into four treatments containing 0% COS (CON), 0.02% COS, 0.04% COS, and 0.08% COS for an 8-day experiment period, with each treatment comprising six replicates. The disappear rates of DM, CP, EE, and total gas production were quadratically increased with increasing COS levels. The disappear rates of DM, CP, EE, and ADF were greatest, whereas the total gas production was lowest in the 0.08% COS group. The pH, NH3-N, MCP, the content of propionate, isobutyrate, butyrate, valerate, and the A/P were quadratically increased with increasing COS levels, while the A/P were linearly decreased. The pH, MCP, and the content of propionate, and butyrate were highest, whereas the NH3-N and the content of acetate, isobutyrate, valerate, and the A/P were lowest in the 0.08% COS group. Microbiomics analysis showed that the rumen microbial diversity was not altered between the CON and the 0.08% COS group. However, the relative abundance of Methanosphaera, Ruminococcus, Endomicrobium, and Eubacterium groups was increased, and the relative abundance of pathogenic bacteria Dorea and Escherichia-Shigella showed a decrease in the 0.08% COS group. Overall, the 0.08% COS was the most effective among the three addition levels, resulting in an increase in the disappearance rate of in vitro fermented nutrients and improvements in rumen fermentation indexes and microbial communities. This, in turn, led to the maintenance of rumen health.

Advances in the preparation, characterization, and biological functions of chitosan oligosaccharide derivatives: A review

Chitosan oligosaccharide (COS), which represent the positively charged basic amino oligosaccharide in nature, is the deacetylated and degraded products of chitin. COS has become the focus of intensive scientific investigation, with a growing body of practical and clinical studies highlighting its remarkable health-enhancing benefits. These effects encompass a wide range of properties, including antibacterial, antioxidant, anti-inflammatory, and anti-tumor activities. With the rapid advancements in chemical modification technology for oligosaccharides, many COS derivatives have been synthesized and investigated. These newly developed derivatives possess more stable chemical structures, improved biological activities, and find applications across a broader spectrum of fields. Given the recent interest in the chemical modification of COS, this comprehensive review seeks to consolidate knowledge regarding the preparation methods for COS derivatives, alongside discussions on their structural characterization. Additionally, various biological activities of COS derivatives have been discussed in detail. Lastly, the potential applications of COS derivatives in biomedicine have been reviewed and presented.

Chitosan oligosaccharide accelerates the dissemination of antibiotic resistance genes through promoting conjugative plasmid transfer

The dissemination of antibiotic resistance genes (ARGs), especially via plasmid-mediated horizontal gene transfer, poses a pervasive threat to global health. Chitosan-oligosaccharide (COS) is extensively utilized in medicine, plant and animal husbandry. However, their impact on microflora implies the potential to exert selective pressure on plasmid transfer. To explore the role of COS in facilitating the dissemination of ARGs via plasmid conjugation, we established in vitro mating models. The addition of COS to conjugation mixtures significantly enhanced the transfer of RP4 plasmid and mcr-1 positive IncX4 plasmid in both intra- and inter-specific. Phenotypic and transcriptome analysis revealed that COS enhanced intercellular contact by neutralizing cell surface charge and increasing cell surface hydrophobicity. Additionally, COS increased membrane permeability by inhibiting the Tol-Pal system, thereby facilitating plasmid conjugative transfer. Furthermore, COS served as the carbon source and was metabolized by E. coli, providing energy for plasmid conjugation through regulating the expression of ATPase and global repressor factor-related genes in RP4 plasmid. Overall, these findings improve our awareness of the potential risks associated with the presence of COS and the spread of bacterial antibiotic resistance, emphasizing the need to establish guidelines for the prudent use of COS and its discharge into the environment.