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    Effect of foliage applied chitosan-based silicon nanoparticles on arsenic uptake and translocation in rice (Oryza sativa L.). Journal of hazardous materials In this study, chitosan-based silicon nanoparticles (Chsi-NPs) are prepared that primarily consists of C (57.9%), O (31.3%), N (5.6%), and Si (3.5%) and are 10-180 nm in size. We then explore the effect on the foliage applied on rice planted on soil contaminated with 104 mg·kg arsenic (As); low (3 mg·L)and high (15 mg·L) doses of the foliar Chsi-NPs are administered during the rice grain filling stage. The results showed that the higher dose foliar Chsi-NPs treatment reduced the As concentration in the grain by 61.2% but increased As concentration in the leaves by 47.1% compared to the control treatment. The foliar spraying of the Chsi-NPs inhibited As transport to the grain by facilitating the attachment of As to the cell wall, with higher doses of the foliar Chsi-NPs treatment increased by 8.7%. The foliar spraying of Chsi-NPs increased the malondialdehyde levels by 18.4%, the catalase activity by 49.0%, and the glutathione activity by 99.0%. These results indicated that the foliar Chsi-NPs application was effective for alleviating As toxicity and accumulation in rice. This study provides a novel method for effectively alleviating As accumulation in rice. 10.1016/j.jhazmat.2022.128781
    A high strength, low friction, and biocompatible hydrogel from PVA, chitosan and sodium alginate for articular cartilage. Luo Chunhui,Guo Andi,Zhao Yufei,Sun Xinxin Carbohydrate polymers Developing articular cartilage substitutes required a combination of high compressive strength, excellent biocompatibility and low friction. Despite great success in tough hydrogels, this combination was hardly realized. Herein, a high strength, low friction, and biocompatible hydrogel was obtained by freezing-thawing polyvinyl alcohol and chitosan aqueous solutions three times, followed with soaking in sodium alginate aqueous solution. Owing to the synergy of crystalline domains, hydrogen bonds, and ionic interactions, the obtained hydrogel exhibited high strength (maximum compressive strength = 141 MPa). Because of the reversible linkages, the gel was also creep-resistant (recovery efficiency = 93%). Benefitted from the negative carboxyl groups from sodium alginate, the water lubrication layer between the gel and the opposing surface was thickened greatly, resulting in a low coefficient of friction (0.044). The biocompatible materials and green progress led to excellent cell compatibility. All these merits made it an ideal substitute for articular cartilage. 10.1016/j.carbpol.2022.119268
    Application of chitosan/alginate nanoparticle in oral drug delivery systems: prospects and challenges. Drug delivery Oral drug delivery systems (ODDSs) have various advantages of simple operation and few side effects. ODDSs are highly desirable for colon-targeted therapy (e.g. ulcerative colitis and colorectal cancer), as they improve therapeutic efficiency and reduce systemic toxicity. Chitosan/alginate nanoparticles (CANPs) show strong electrostatic interaction between the carboxyl group of alginates and the amino group of chitosan which leads to shrinkage and gel formation at low pH, thereby protecting the drugs from the gastrointestinal tract (GIT) and aggressive gastric environment. Meanwhile, CANPs as biocompatible polymer, show intestinal mucosal adhesion, which could extend the retention time of drugs on inflammatory sites. Recently, CANPs have attracted increasing interest as colon-targeted oral drug delivery system for intestinal diseases. The purpose of this review is to summarize the application and treatment of CANPs in intestinal diseases and insulin delivery. And then provide a future perspective of the potential and development direction of CANPs as colon-targeted ODDSs. 10.1080/10717544.2022.2058646
    Chitosan-modified biochar: Preparation, modifications, mechanisms and applications. International journal of biological macromolecules The chitosan-modified biochar composite, as a carbohydrate polymer, has received increasing attention and becomes a research hotspot. It is a promising impurity adsorption material, which has potential application value in the agricultural environment fields such as soil improvement and sewage purification. The composite can combine the advantages of biochar with chitosan, and the resulting composite usually exhibits a great improvement in its surface functional groups, adsorption sites, stability, and adsorption properties. In addition, compared to other adsorbents, the composite truly achieves the concept of "waste control by waste". In this paper, the preparation method, composite classification, adsorption mechanism, and models of biochar modified by chitosan are introduced, meanwhile, we also review and summarize their effects on the decontamination of wastewater and soil. In addition to common heavy metal ions, we also review the adsorption and removal of some other organic/inorganic pollutants, including (1) drug residues; (2) dyes; (3) phosphates; (4) radionuclides; (5) perfluorochemicals, etc. Moreover, challenges and prospects for the composite are presented and further studies are called for the chitosan-biochar composite. We believe that the composite will lead to further achievements in the field of environmental remediation. 10.1016/j.ijbiomac.2022.04.006
    A combined approach using slightly acidic electrolyzed water spraying and chitosan and pectin coating on the quality of the egg cuticle, prevention of bacterial invasion, and extension of shelf life of eggs during storage. Food chemistry Slightly acidic electrolyzed water (SAEW) is often used on eggs to remove microorganisms, but the cuticle will be damaged, causing bacterial invasion and deterioration of egg quality during preservation. Therefore, a combination of SAEW disinfection with chitosan (CS) and pectin (PT) composite coating (CS + PT) was tried in preventing bacterial invasion and prolonging the shelf life of eggs. The results showed the order of decontamination effectiveness on contaminated eggs was SAEW > Electrolyzed reduced water (ERW) + SAEW > ERW > deionized water. The CS + PT coating used on SAEW-disinfected eggs inhibits the S. enteritidis invasion (reduced by 63.3%) and was successfully used to maintain the quality of eggs (Haugh unit 48.63, Weight loss 7.34%, Yolk index 0.29, pH 8.93) after 8 weeks storage at 25 ℃. The results revealed that the combination of SAEW and CS + PT was a very promising method for egg preservation. 10.1016/j.foodchem.2022.133129
    A Combination of Recombinant HA1-and Nucleoprotein-Based Chitosan Nanoparticles Induces Early and Potent Immune Responses Against the H9N2 Influenza Virus. Viral immunology The effectiveness of inactivated H9N2 influenza vaccines is doubtful due to changes in antigenic regions of the virus hemagglutinin (HA) protein. One strategy for the development of the efficacious vaccine is the use of nanoparticles that display more immunogenic regions of the influenza virus. In this study, chitosan (CS)-based nanoparticles were developed as a delivery system for intranasal immunization using recombinant H9N2 virus HA1 and nucleoprotein (NP), for the induction of humoral and cellular responses. CS-HA1 and CS-NP nanoparticles were prepared by the ionic gelation method and characterized for their physicochemical properties and shape. The immunogenicity and the protective efficacy were evaluated by measuring antibody titers, T cell proliferation response, CD4/CD8 ratio, and quantitative real-time RT-PCR following intranasal administration of the prepared nanoparticles alone or in combination in chickens compared to an inactivated H9N2 vaccine. The average size, surface charge, and spherical structure of the synthesized nanoparticles showed high quality. Serologic analysis revealed that the immunization of inactivated vaccine groups resulted in strong influenza antibodies, which were significantly ( < 0.05) higher compared to the other groups. The vaccinated chickens with CS-HA1+CS-NP developed higher specific anti-influenza antibodies than in those vaccinated with each of rHA1 and rNP. Administration of a combination of the protein-based nanoparticles has stimulated the activation of both CD4 and CD8T cells and induced a significantly higher T cell proliferation. The viral shedding was significantly lower in CS-HA1+CS-NP and inactivated vaccine groups compared with other challenged groups. The data demonstrate the potential of CS-HA1+CS-NP nanoparticles for eliciting specific influenza antibodies and conferring protection in chickens. 10.1089/vim.2021.0207
    Functionalized chitosan as a promising platform for cancer immunotherapy: A review. Carbohydrate polymers Immunotherapy is an emerging treatment option for use following traditional cancer treatments (surgical resection, radiotherapy and chemotherapy). Due to the complexity of the tumor environment, a single immunotherapy drug cannot readily reach the target site and frequently causes adverse reactions. Chitosan has been used in this emerging field because of its biodegradable, biocompatible, nonimmunogenic and nontoxic properties. Chitosan has been used as a carrier of immunotherapeutic agents to improve bioavailability, regulate the immune system and enhance antitumor response. The easily modified structure of chitosan allows for the construction of many different delivery vectors for better application in immunotherapy. Here, we review the recent applications of chitosan and its derivatives as delivery vectors in cancer immunotherapy, as well as discuss limitations and clarify current trends and future directions. In conclusion, chitosan has a promising future as a delivery material in immunotherapy. 10.1016/j.carbpol.2022.119452
    Mucosal immunity of mannose-modified chitosan microspheres loaded with the nontyepable Haemophilus influenzae outer membrane protein P6 in BALB/c mice. PloS one Nontypeable Haemophilus influenzae (NTHi) is a common opportunistic pathogen that colonizes the nasopharynx. NTHi infections result in enormous global morbidity in two clinical settings: otitis media in children and acute exacerbation of chronic obstructive pulmonary disease (COPD) in adults. Thus, there is an urgent need to design and develop effective vaccines to prevent morbidity and reduce antibiotic use. The NTHi outer membrane protein P6, a potential vaccine candidate, is highly conserved and effectively induces protective immunity. Here, to enhance mucosal immune responses, P6-loaded mannose-modified chitosan (MC) microspheres (P6-MCMs) were developed for mucosal delivery. MC (18.75%) was synthesized by the reductive amination reaction method using sodium cyanoborohydride (NaBH3CN), and P6-MCMs with an average size of 590.4±16.2 nm were successfully prepared via the tripolyphosphate (TPP) ionotropic gelation process. After intranasal immunization with P6-MCMs, evaluation of humoral immune responses indicated that P6-MCMs enhance both systemic and mucosal immune responses. Evaluation of cellular immune responses indicated that P6-MCMs enhance cellular immunity and trigger a mixed Th1/Th2-type immune response. Importantly, P6-MCMs also trigger a Th17-type immune response. They are effective in promoting lymphocyte proliferation and differentiation without toxicity in vitro. The results also demonstrate that P6-MCMs can effectively induce MHC class I- and II-restricted cross-presentation, promoting CD4+-mediated Th immune responses and CD8+-mediated cytotoxic T lymphocyte (CTL) immune responses. Evaluation of protective immunity indicated that immunization with P6-MCMs can reduce inflammation in the nasal mucosa and the lung and prevent NTHi infection. In conclusion, MCMs are a promising adjuvant-delivery system for vaccines against NTHi. 10.1371/journal.pone.0269153
    Antibiotic-Loaded Amphiphilic Chitosan Nanoparticles Target Macrophages and Kill an Intracellular Pathogen. Small (Weinheim an der Bergstrasse, Germany) In this work, levofloxacin (LVX), a third-generation fluoroquinolone antibiotic, is encapsulated within amphiphilic polymeric nanoparticles of a chitosan-g-poly(methyl methacrylate) produced by self-assembly and physically stabilized by ionotropic crosslinking with sodium tripolyphosphate. Non-crosslinked nanoparticles display a size of 29 nm and a zeta-potential of +36 mV, while the crosslinked counterparts display 45 nm and +24 mV, respectively. The cell compatibility, uptake, and intracellular trafficking are characterized in the murine alveolar macrophage cell line MH-S and the human bronchial epithelial cell line BEAS-2B in vitro. Internalization events are detected after 10 min and the uptake is inhibited by several endocytosis inhibitors, indicating the involvement of complex endocytic pathways. In addition, the nanoparticles are detected in the lysosomal compartment. Then, the antibacterial efficacy of LVX-loaded nanoformulations (50% w/w drug content) is assessed in MH-S and BEAS-2B cells infected with Staphylococcus aureus and the bacterial burden is decreased by 49% and 46%, respectively. In contrast, free LVX leads to a decrease of 8% and 5%, respectively, in the same infected cell lines. Finally, intravenous injection to a zebrafish larval model shows that the nanoparticles accumulate in macrophages and endothelium and demonstrate the promise of these amphiphilic nanoparticles to target intracellular infections. 10.1002/smll.202201853
    Fabrication of chitosan based luminescent nanoprobe with aggregation-induced emission feature through ultrasonic treatment. Carbohydrate polymers Chitosan is an abundant natural polysaccharide that contains a lot of amino and hydroxyl groups. It possesses great potential for biomedical applications owing to its low toxicity, biodegradability and low cost. Herein, a novel chitosan-based fluorescent copolymer (WS-CS-TPA) was designed and synthesized via nucleophilic substitution of hexachlorocyclotriphosphazene (HCCP), water-soluble chitosan (WS-CS) and an aggregation-induced emission (AIE) fluorogen (AIEgen) triphenylamine derivative (TPA-NH). Under ultrasonic treatment, 1.16 g TPA-NH and 1.1 g WS-CS can be conjugated by 0.7 g HCCP at room temperature. The obtained copolymer shows amphiphilic property and could assemble into nanoparticles with size about 100 nm. After self-assembly, TPA-NH was aggregated in the core, thus exhibiting superb AIE feature with intense green fluorescence emission in aqueous media. On the other hand, hydrophilic WS-CS was coated on the surface of nanoparticles and endowed their high water dispersibility. Results from preliminary biological assays suggested that WS-CS-TPA can be internalized by cells and exhibits low cytotoxicity, suggesting their great potential for biological imaging and intracellular drug delivery. 10.1016/j.carbpol.2022.119487
    Nanofibrous polycaprolactone/chitosan membranes for preventing postsurgical tendon adhesion. Journal of biomedical materials research. Part B, Applied biomaterials Peritendinous adhesion is considered a major postsurgical tendon complication in hand surgery. This complication could be mitigated partially through early tendon mobilization. However, development of new treatment modalities to guide tissue regeneration and to reduce postsurgical tendon adhesion has recently gained attentions. In this article, synthesis and characterization of electrospun nanofibrous membranes (NFMs) of polycaprolactone (PCL) and chitosan to form a physical barrier against cellular migration leading to tendon adhesion is presented. The mechanical properties of the NFMs are modulated to maintain high integrity during postsurgical tendon mobilization. The tensile strength of the NFMs is examined in wet and dry conditions after 1000 cyclic pull loadings. In addition, the mechanical strength of the NFMs is evaluated after a degradation period of 30 days. To obtain NFM with desired properties, concentrations of polymer solutions, operation parameters of electrospinning and the thickness of NFMs were optimized. Based on the biodegradation and mechanical evaluations, the optimum NFM was obtained for specified amounts of PCL (5 wt %) + chitosan (2 wt %) at an electrospinning drum speed of 400 rpm. The engineered NFM could withstand forces of 33 and 19 N before and after 1000 pull cycles that are sufficient during tendon healing process. The bonding of chitosan fibers over PCL nanofibers allowed for production of NFMs with appropriate mechanical integrity and degradation rate. In vitro cell culture tests demonstrated that PCL/chitosan could only have minor impact on decreasing fibroblast attachment over the membranes probably due to protonation of amine groups. 10.1002/jbm.b.34999
    Removal of Pb (II) and V (V) from aqueous solution by glutaraldehyde crosslinked chitosan and nanocomposites. Chen Menghua,Yu Mengdie,Kang Runfeng,Sun Huimin,Zhang Wang,Wang Shengsen,Wang Nong,Wang Jun Chemosphere In this paper, new adsorbents with high mechanical strength chitosan-graphene oxide (CS-GO) and chitosan-titanium dioxide (CS-TiO) were synthesized by using glutaraldehyde as crosslinking agent, and the adsorption behavior of Pb (II) and V (V) on them were investigated. The materials were characterized by scanning electron microscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The effects of initial metal ion concentration and contact time on the removal of V (V) and Pb (II) by CS-GO and CS-TiO were investigated. Characterization results showed that the hydroxyl group of GO/TiO reacted with the amino group of chitosan. A comparison of the kinetic models against experimental data showed that the kinetics react system was best described by the pseudo-second-order model. indicating that chemical adsorption was the main adsorption force. the Langmuir adsorption model and Freundlich model agreed well with the experimental data. The removal capacity of Pb (II) by CS-GO and CS-TiO were lower than those of V (V). The uncross-linked -OH and CO were the main adsorptive sites for Pb (II) removal, while uncross-linked -OH and -NH played an important role in removing V (V). These findings provided insights on the removing lead and vanadium pollution. 10.1016/j.chemosphere.2022.134084
    Fabrication and investigation of novel monochloroacetic acid fortified, tripolyphosphate-crosslinked chitosan for highly efficient adsorption of uranyl ions from radioactive effluents. Journal of hazardous materials Chitosan crosslinked with potassium tripolyphosphate (CTPP) and monochloroacetic-acid-modified chitosan crosslinked with potassium tripolyphosphate (MCTPP) were synthesized for removing UO from acidic radioactive effluents. The influential factors, operational requirements, and interactive mechanisms of the adsorption process were systematically investigated. The mesh-structured composites adsorbed UO most effectively at pH 5.0. The maximum adsorption capacities for pure chitosan, CTPP, and MCTPP were 374.93, 780.89, and 1487.72 mg/g, respectively. Batch experiments indicated that the pH and adsorbent dose strongly influenced UO adsorption. MCTPP could adsorb most UO within 15 min, and equilibrium was reached by ~1 h. The adsorption isotherms indicated that UO adsorption by MCTPP may be an endothermic single-layer adsorption process. Moreover, common metal ions in single-metal systems only slightly affected this process. The results of instrumental characterization and natural water application suggested that the highly developed pore structure and abundant tripolyphosphate groups in synthesized composites were dominant adsorption contributors besides amino and hydroxyl groups. Successful development of the novel material for efficiently adsorbing UO and identification of the adsorption mechanism will provide valuable guidance to chitosan modification and further remediation practices of radioactive effluents. 10.1016/j.jhazmat.2022.128461
    Biomimetic development of chitosan and sodium alginate-based nanocomposites contains zirconia for tissue engineering applications. Journal of biomedical materials research. Part B, Applied biomaterials Nanostructured materials possess unique structural and functional properties that play a crucial position in tissue engineering applications. Present investigation is aimed to synthesize chitosan-sodium alginate (CS) nanocomposite using hydrothermally prepared zirconia nanoparticles. In this, three different weight percentages of (0.5, 1, and 1.5) zirconia nanoparticles are utilized for the preparation of biomimetic nanocomposite scaffolds (CSZ) employing 4 wt% of CS by a solvent casting technique. Physico-chemical and thermal behavior of the prepared nanoparticles and their CSZ scaffolds are comprehensively characterized. Bioactivity of the prepared zirconia nanoparticles and CSZ scaffolds are explored in terms of in vitro biocompatibility, protein absorption in simulated body fluid (SBF), and phosphate buffered saline (PBS). Agar disc diffusion method is employed to identify the antibacterial property against Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity of zirconia nanoparticles and CSZ scaffolds is identified against human urothelial carcinoma (UC6) and osteosarcoma (MG-63) cells. These studies explore that zirconia nanoparticles are suitable for biomedical applications while it is interacted with chitosan and sodium alginate (CS) due to their promising biocompatibility. Biomimetically obtained chitosan/sodium alginate scaffold contain 1 wt% zirconia nanoparticles show higher biocompatibility amenable for tissue engineering applications. 10.1002/jbm.b.35052
    Mixing efficiency affects the morphology and compactness of chitosan/tripolyphosphate nanoparticles. Carbohydrate polymers Due to the rapid reaction kinetics, the morphology of chitosan/tripolyphosphate nanoparticles was difficult to control. We mixed chitosan and tripolyphosphate through a multi-inlet vortex mixer at different mixing efficiency and characteristic mixing time (τ). Below a critical τ, the aggregation of primary chitosan/TPP particles can be ceased. The corresponding aggregation time of primary particles (τ) was dependent on the ionic strength, the degree of deacetylation and molecular weight of chitosan. Moreover, the particle compactness was estimated from the hydrodynamic diameter and the turbidity using a model based on the Mie theory. Slow and nonhomogeneous mixing led to more compact nanoparticles, while rapid and homogeneous mixing produced nanoparticles with a higher swelling ratio. Besides, the ionic strength and polymer concentration could affect the internal structure of nanoparticles. This study revealed the significance of mixing on the internal structure of chitosan/TPP nanoparticles, which could guide the preparation of other ionically-crosslinked polysaccharide colloids. 10.1016/j.carbpol.2022.119331
    Green and eco-friendly approaches for the extraction of chitin and chitosan: A review. Carbohydrate polymers Chitin is one of the most diverse and naturally occurring biopolymers, and it is mainly present in crustaceans, insects, and fungi. Chitosan is derived from chitin by deacetylation process. It is important to note that the conventional chemical method of extracting chitin includes disadvantages and it poses various environmental issues. Recently, the green extraction techniques have perceived substantial development in the field of polymer chemistry. A variety of methods have been successfully developed using green extraction techniques for extracting chitin and chitosan from various resources. It includes the use of ionic liquids (ILs), deep eutectic solvents (DES), microbial fermentation, enzyme-assisted extraction (EAE), microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE), subcritical water extraction (SWE), and electrochemical extraction (ECE). In this review, the extraction of chitin and chitosan using greener approaches were summarized. In addition, challenges, opportunities and future perspectives of green extraction methods have also been narrated. 10.1016/j.carbpol.2022.119349
    Chitosan nanomaterials: A prelim of next-generation fertilizers; existing and future prospects. Carbohydrate polymers Global agriculture is urgently seeking ways to mitigate the detrimental effects of conventional chemical fertilizers on the environment. Biodegradable, eco-friendly, renewable energy-sourced next-generation fertilizers could be an answer, allowing for improved nutrient use efficiency and a lower environmental footprint. During the last decade, agricultural research on chitosan nanomaterials (NMs) has expanded, demonstrating their usefulness in enhancing agricultural output not only as plant immune boosters but also via slow, controlled and target delivery of nutrients to plants. Chitosan NMs natively act as an abundant nutrient source of C (54.4-47.9 wt%), O (42.3-30.19 wt%), N (7.6-5.8 wt%), and P (6.1-3.4 wt%) to plants. Moreover, chitosan NMs can further functionalized by more nutrients payloads through its functional groups. The current review investigates the technical features of chitosan NMs as prospective next-generation fertilizers based on rationales. The review offers crucial insights into future directions, sources, production capacity of chitosan-based next-generation nanofertilizers for industrial-scale manufacturing. 10.1016/j.carbpol.2022.119356
    Preparation and performance evaluation of chitosan/polyvinylpyrrolidone/polyvinyl alcohol electrospun nanofiber membrane for heavy metal ions and organic pollutants removal. International journal of biological macromolecules In this work, a novel electrospun chitosan (CS)/polyvinylpyrrolidone (PVP)/polyvinyl alcohol (PVA) nanofibrous membrane was prepared to remove heavy metal ions and organic pollutants from water. The nanofiber morphologies were adjusted through the optimal electrospinning process parameters. Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterizations indicated that a well-crosslinked CS/PVP/PVA nanofiber film was formed. Under the optimize conditions, the obtained CS/PVP/PVA nanofiber membranes exhibited porous and uniform nanofibrous structures with an average diameter of 160 nm and a pure water permeability of 4518.91 L·m·h·bar. In addition, the adsorption and separation performance of CS/PVP/PVA nanofiber membranes were evaluated with Cu(II), Ni(II), Cd(II), Pb(II) and Methylene Blue (MB), Malachite Green (MG) as target ions and dyes. The results showed that the retention rate of CS/PVP/PVA nanofiber membranes for Cu(II), Ni(II), Cd(II), Pb(II), MG and MB can reach 94.20%, 90.35%, 83.33%, 80.12%, 84.01% and 69.91%, respectively. The adsorption capacities of Cu(II), Ni(II), Cd(II), Pb(II), MG and MB were 34.79, 25.24, 18.07, 16.05, 17.86 and 13.27 mg g. The adsorption kinetics of heavy metal ions and dyes by the nanofiber membranes can be explained by the Langmuir isotherm model and represented by the pseudo-second-order kinetic mechanism that determined the spontaneous chemisorption process. This study provides a synthetic approach to membranes for the removal of organic and heavy metal micropollutants from water. 10.1016/j.ijbiomac.2022.05.017
    Preparation, characterization and antibacterial activity of new ionized chitosan. Carbohydrate polymers In order to improve the solubility and antibacterial activity of chitosan and expand its application range, ionized chitosan (ICS) was successfully synthesized from chitosan through methylation and sulfonation reactions in this study. The chemical structures of the polymers were verified by Fourier transform infrared spectroscopy (FTIR) and H NMR, and a series of characterizations of the polymer were carried out by analytical methods such as element analysis (EA), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results showed that the water solubility of the modified ICS was significantly improved. The introduction of propyl sulfonic acid groups with particle size decreasing and potential increasing greatly improved the antibacterial activity of chitosan, indicating that the ICS had the potential as a water-soluble antibacterial agent. 10.1016/j.carbpol.2022.119490
    An injectable antibacterial chitosan-based cryogel with high absorbency and rapid shape recovery for noncompressible hemorrhage and wound healing. Biomaterials Great challenges remain in the effective control of irregular and incompressible deep wound bleeding and the promotion of wound healing after bacterial infection. In this study, cryogels were prepared using an ice template based on chitosan (CS), oxidized gallic acid (OGA) and hemin (HE), which are all green edible materials. The cryogels exhibit rapid blood-triggered shape recovery and a high swelling ratio. The cryogels with 5 mg mL HE (Gel-CS/OGA@HE5) exert excellent photothermal effects. Additionally, the cryogels have excellent cytocompatibility and blood clotting abilities. In the mouse liver injury model and mouse tail amputation model, Gel-CS/OGA@HE5 presents better hemostasis properties than gauze and a gelatin sponge. Moreover, Gel-CS/OGA@HE5 displays excellent healing performance as a wound dressing. Overall, we provide a simple and effective strategy to prepare cryogels for controlling wound bleeding and promoting wound healing. 10.1016/j.biomaterials.2022.121546
    Wound dressing membranes based on immobilized Anisaldehyde onto (chitosan-GA-gelatin) copolymer: In-vitro and in-vivo evaluations. International journal of biological macromolecules Herein, wound dressing membranes based on covalently linked Chitosan (Ch) to Gelatin (GE) via Glutaraldehyde (GA) to have (Ch-GA-GE) copolymer have been developed. In addition, Anisaldehyde (An) was immobilized onto Ch-GA-GE to has An-(Ch-GA-GE) membrane. The changes of the Ch-GA-GE membranes wettability, from 26 ± 1.3° to 45.3 ± 2.27° of the An-(Ch-GA-GE) copolymer membrane, indicating the reduction of copolymers hydrophilicity. The thermal characterization was done using TGA and DSC, while the morphological analysis was done using SEM. The antibacterial properties were assessed against four bacterial strains (P. aeruginosa, S. aureus, Streptococcus, and E. coli). In-vitro evaluation of the fabricated membranes to be used as wound dressings was investigated by measuring their hemocompatibility, cytotoxicity, and biodegradability. Finally, the in-vivo assessment of the developed membranes to encourage skin regeneration was assessed utilizing adult Wistar albino rats. The results illustrated that the An-(Ch-GA-GE) copolymer membranes significantly enhanced the rat's full-thickness injuries, as monitored by reducing the wound region. Furthermore, histological analyses of the injuries covered with An-(Ch-GA-GE) membranes demonstrated a notable re-epithelialisation contrasted with wounds treated with the cotton gauze Ch-GA-GE membranes dressings proving the efficiency of Anisaldehyde. Those findings indicate that the An-(Ch-GA-GE) membrane has considerable potential for wound healing and skin regeneration. 10.1016/j.ijbiomac.2022.05.061
    Effects of chitosan-based coatings incorporated with ɛ-polylysine and ascorbic acid on the shelf-life of pork. Food chemistry Chitosan is a food thickener with film-forming ability and antibacterial activity. ɛ-Polylysine is a preservative with broad-spectrum antibacterial activity. Ascorbic acid is a food antioxidant. In this study, pork chunks were treated with four dipping solutions, i.e. purified water (control), 0.2% ascorbic acid (treatment-1), 0.02% ɛ-polylysine (treatment-2), and 0.4% chitosan + 0.02% ɛ-polylysine + 0.2% ascorbic acid (treatment-3), and stored at 3 °C for 12 days. All treatments suppressed bacterial growth, increases in pH and total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substances and decreases in the red indices of pork chunks compared with the control during refrigeration. Based on the national standards of total bacterial number and TVB-N of pork, treatment-3 extended the shelf-life of pork chunks by six days compared with the control. The results verified that chitosan-based coatings may be a practical method for the preservation of pork chunks during refrigeration. 10.1016/j.foodchem.2022.133206
    Chitosan-enhanced nonswelling hydrogel with stable mechanical properties for long-lasting underwater sensing. International journal of biological macromolecules Existing anti-swelling hydrogels with poor mechanical strength restrict their underwater human monitoring as wearable electronic sensing equipment. Herein, a nonswelling double network (DN) hydrogel with strong self-recoverability (97.22%) was developed by adding chitosan (CS) to poly(acrylic acid-2-methoxyethyl acrylate)-Fe [P(AA-MEA)-Fe] network. Owing to the introduction of CS, the hydrogel displayed excellent nonswelling properties under aqueous solutions (pH = 1, 4 and 7), physiological saline, seawater, dodecane, n-hexane and chloroform. Besides, CS improved mechanical properties of hydrogel through non-covalent network (large stretchability of 1199%, tensile strength of 0.462 MPa and toughness of 2.01 MJ/m). Surprisingly, the hydrogel still reached the extensibility (1072%) and tensile stress (0.467 MPa) even after immersing in water for 7 days. Fabricating hydrogel as flexible strain sensor, periodic real-time signals of human movements (e.g., joint actions and electronic skin touching) were accurately monitored under the water and seawater. The nonswelling P(AA-MEA)-CS-Fe hydrogel shows huge potential in underwater sensing. 10.1016/j.ijbiomac.2022.05.102
    A dual-function chitosan packaging film for simultaneously monitoring and maintaining pork freshness. Food chemistry Exploring food packaging films simultaneously possess freshness monitoring and maintaining can effectively tackle food safety issues. Here, we constructed a chitosan/N-doped carbon dots (CS/N-CDs) film which can monitor the freshness of pork based on pH-mediated fluorescent sensing and extend the shelf life based on the antioxidant, antibacterial and UV shielding properties. The fluorescent intensity of CS/N-CDs films increased with the increase of pork pH from 5.77 to 6.84 which positively related to the change of TVB-N from 6.68 to 17.53 mg/100 g. CS/N-CDs films had a maintaining effect on pork freshness corroborated by the scavenging activity on DPPH and ABTS radicals and antibacterial efficiency and inhibition zones of S. aureus and E.coli, and the total viable count, a value, weight loss, hardness and springiness of pork. Cell viability and hemolytic activity assay proved that CS/N-CDs films was safe. A novel chitosan-based intelligent and active food packaging film was provided. 10.1016/j.foodchem.2022.133242
    Regulating the Physicochemical Properties of Chitosan Films through Concentration and Neutralization. Foods (Basel, Switzerland) Chitosan offers real potential for use in food preservation, biomedicine, and environmental applications due to its excellent functional properties, such as ease in the fabrication of large films, biocompatibility, and antibacterial properties. However, the production and application of chitosan films were limited by their strong residual acetic acid taste, weak mechanical properties, and poor water vapor barrier properties. In this study, the effects of the chitosan concentration in the film-forming solutions and the neutralization treatment on the physicochemical properties of chitosan films were examined. The results demonstrated that the chitosan concentration affected the mechanical and barrier properties of chitosan films without the neutralization treatment. This was mainly due to the low acetic acid contents in chitosan films after drying. Acetic acid acted as a plasticizer within chitosan films resulting in a looser network structure. After neutralization, the chitosan films showed improvements in properties, with little effect on the chitosan concentration in the film-forming solutions. Moreover, chitosan films after neutralization showed no residual acetic acid. Therefore, neutralization could effectively improve the performance of chitosan films. 10.3390/foods11111657
    Chitosan: Applications in Drug Delivery System. Mini reviews in medicinal chemistry Chitin and chitosan have unique structures with significant functional groups carrying useful chemical capabilities. Chitin and chitosan are acknowledged as novel biomaterials with advantageous biocompatibility and biodegradability. Chitosan is a polysaccharide that is made from chitin. There have been several attempts to employ this biopolymer in the biomedical area. This material's application in the production of artificial skin, drug targeting, and other areas is explored. The most prevalent strategies for recovering chitin from sea organisms are described and various pharmacological and biological uses are discussed. This review article targets drug delivery with the help of chitosan derived nanomaterial. The drug delivery system applications through nonmaterial have encountered a considerable role in the pharmaceutical, medical, biological, and other sectors in recent years. Nanomaterials have advanced applications as novel drug delivery systems in many fields, especially in industry, biology, and medicine. In the biomedical and pharmaceutical arena, the natural polymer-based nanoparticulate method has now been widely studied as particulate vehicles. By mixing alginate with other biopolymers, by immobilizing specific molecules such as sugar molecules and peptides by chemical or physical cross-linking, different properties and structures such as biodegradability, gelling properties, mechanical strength, and cell affinity can be obtained. Owing to their inherent ability to deliver both hydrophilic and hydrophobic drug molecules, increase stability, decrease toxicity, and enhance commonly formulated medications, these particles are now widely used in imaging and molecular diagnostics, cosmetics, household chemicals, sunscreens, radiation safety, and novel drug delivery. 10.2174/1389557522666220609102010
    Delivery LL37 by chitosan nanoparticles for enhanced antibacterial and antibiofilm efficacy. Carbohydrate polymers In this study, the fabrication of LL37-loaded chitosan nanoparticles (CS/LL37-NPs) was based on an ionotropic gelation method between sodium tripolyphosphate (TPP) and chitosan. Synthesized chitosan nanoparticles (CS-NPs) were approved by Fourier Transform Infrared (FTIR), UV-vis spectroscopy, Dynamic Light Scattering (DLS), Scanning Electron Microscope (SEM), and Transmission Electron Microscopy (TEM). The encapsulation efficiency of LL37 in this delivery system (CS/LL37-NPs) was 86.9%. According to in vitro release profile, the release of LL37 from CS/LL37-NPs was almost complete after 5 days. Additionally, CS/LL37-NPs can cause an increase in the half-life and prolonged LL37 antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA). This delivery system demonstrated 68% biofilm formation inhibition compared to the LL37 alone. Also, icaA gene expression in the face of CS/LL37-NPs was significantly decreased. This study showed the important role of delivery systems in enhancing LL37 antibacterial and antibiofilm activity which can be suggested as a promising agent in the inhibition of bacterial growth and the prevention of biofilm formation. 10.1016/j.carbpol.2022.119634
    A novel chitosan oligosaccharide derivative: Synthesis, antioxidant and antibacterial properties. Carbohydrate polymers A novel thioether chitosan oligosaccharide (COS-All-Tio) was prepared by the reaction of chitosan oligosaccharide (COS) with 3-bromopropene, followed by the coupling with tiopronin (Tio) using a thiol-ene reaction. The degree of substitution of COS-All-Tio reached 1.48. The structure of COS-All-Tio was identified by IR, NMR spectra. It was found that COS-All-Tio possessed more potent antioxidant activities than COS. The IC values of COS-All-Tio for scavenging DPPH, ABTS and OH were 0.31, 0.39 and 0.73 mg/mL, respectively, while the corresponding values for COS were 0.66, 2.89 and 1.41 mg/mL, respectively. COS-All-Tio was also found to possess much stronger antibacterial effect than COS against five bacteria strains (Staphylococcus aureus, Bacillus subtilis, Listeria monocytogenes, Escherichia coli and Pseudomonas aeruginosa). Further, COS-All-Tio was found to be non-toxic to RAW264.7 macrophages and MRC-5 human lung cells. This work provides a convenient way to improve the antioxidant and antibacterial activities of COS. 10.1016/j.carbpol.2022.119608
    Molecular modifications, biological activities, and applications of chitosan and derivatives: A recent update. Chirality Polysaccharides arouse great interest due to their structure and unique properties, such as biocompatibility, biodegradability, and absence of toxicity. Polysaccharides from marine sources are particularly useful due to the wide variety of applications and biological activities. Chitosan, a deacetylated derivative of chitin, is an example of an interesting bioactive marine-derived polysaccharide. Moreover, a wide variety of chemical modifications and conjugation of chitosan with other bioactive molecules are responsible for improvements in physicochemical properties and biological activities, expanding the range of applications. An overview of the synthetic approaches for preparing chitosan, chitosan derivatives, and conjugates is described and discussed. A recent update of the biological activities and applications in different research fields, mainly focused on the last 5 years, is presented, highlighting current trends. 10.1002/chir.23477