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The multifunctional active smart biomass film was prepared by incorporating chitosan-adsorbed laurate esterified starch curcumin Pickering emulsion into the starch film matrix, with nano-cellulose serving as reinforcing agents. The mechanical and functional properties of the film were studied, and the film was used to monitor the freshness of pork. The results demonstrated a relatively uniform distribution of curcumin and Pickering emulsion droplets within the film matrix. Furthermore, the thermal stability was minimally impacted by the introduction of curcumin Pickering emulsion, while the tensile strength and tensile strain of the film were increased, and both its hydrophobicity and antioxidant properties were improved. The free radical scavenging rate reached 56.01 %, with sustained high antioxidant capacity even after 8 days. Additionally, the presence of curcumin provided the film with pH indicating ability and delayed pork spoilage. Therefore, this work provides an attractive strategy for constructing green, active, and smart biomass packaging films for meat packaging applications., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Treatment of infected wound by simultaneously eliminating bacteria and inducing angiogenesis to promote wound tissue regeneration remains a clinical challenge. Dynamic and reversable hydrogels can adapt to irregular wound beds, which have raised great attention as wound dressings. Herein, a sprayable chitosan-based hydrogel (HPC/CCS/ODex-IGF1) was developed using hydroxypropyl chitosan (HPC), caffeic acid functionalized chitosan (CCS), oxidized dextran (ODex) to crosslink through the dynamic imine bond, which was pH-responsive to the acidic microenvironment and could controllably release insulin growth factor-1 (IGF1). The HPC/CCS/ODex-IGF1 hydrogels not only showed self-healing, self-adaptable and sprayable properties, but also exhibited excellent antibacterial ability, antioxidant property, low-cytotoxicity and angiogenetic activity. In vivo experiments demonstrated that hydrogels promoted tissue regeneration and healing of bacteria-infected wound with a rate of approximately 98.4 % on day 11 by eliminating bacteria, reducing inflammatory and facilitating angiogenesis, demonstrating its great potential for wound dressing., Competing Interests: Declaration of competing interest The author declare that they have no competing financial interests or personal relationships that could have appeared to influence the work reported in the paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The development of highly effective chitosan-based hemostatic materials that can be utilized for deep wound hemostasis remains a considerable challenge. In this study, a hemostatic antibacterial chitosan/N-hydroxyethyl acrylamide (NHEMAA)/Ti 3 C 2 T x (CSNT) composite cryogel was facilely prepared through the physical interactions between the three components and the spontaneous condensation of NHEMAA. Because of the formation of strong crosslinked network, the CSNT cryogel showed a developed pore structure (~ 99.07 %) and superfast water/blood-triggered shape recovery, enabling it to fill the wound after contacting the blood. Its capillary effect, amino groups, negative charges, and affinity with lipid collectively induced rapid hemostasis, which was confirmed by in vitro and in vivo analysis. In addition, CSNT cryogel showed excellent photothermal antibacterial activities, high biosafety, and in vivo wound healing ability. Furthermore, the presence of chitosan effectively prevented the oxidation of MXene, thus enabling the long-term storage of the MXene-reinforced cryogel. Thus, our hemostatic cryogel demonstrates promising potential for clinical application and commercialization, as it combines high resilience, rapid hemostasis, efficient sterilization, long-term storage, and easy mass production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

3D multifunctional scaffold has been designed based on Cs/SA/NS/NPHA. Nanoparticles hydroxyapatite (NPHA) was prepared via precipitation method of sodium dihydrogen phosphate in presence calcium chloride. Different ratios of Chitosan (CS)/Sodium Alginate (SA) were used to prepare Cs/SA scaffolds in presence of CaCl 2 as a cross linker. NPHA was incorporated in CS/SA scaffold and neomycin sulfate (NS) was added as an antimicrobial agent. The structure and surface morphology of the scaffolds were investigated via infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and thermal gravimetric analysis (TGA) techniques. Additionally, Antimicrobial activity of the scaffold has evaluated against Gram- negative and Gram- positive bacteria. The result showed promising antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. Furthermore, cytotoxicity against MG63 osteosarcoma cell and fibroblast normal cell line has investigated. The result showed anti-proliferative against MG63. DFT calculations and molecular docking were used to study the reactivity of the compounds. The results exhibited that Cs/SA/NS/NPHA is potent expected to be used in bone tissue regeneration., Competing Interests: Declaration of competing interest The author declares that there is no conflict to interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This work focuses on the influence of ozone pretreatment on the fractionation and solubilization of sugarcane bagasse and soda bagasse pulp fibers in sodium hydroxide/urea solution, as well as the application of regenerated cellulose for producing edible films. The methodology involved pretreating lignocelluloses with ozone for 20 to 120 min before dissolving in sodium hydroxide/urea solution. The influence of the pretreatment conditions on cellulose dissolution yield was investigated. Regenerated cellulose films were then formed, with and without the addition of 2 % chitosan. Mechanical, physical, structural, thermal, and antimicrobial attributes were determined as a function of ozonation conditions of raw materials and chitosan content. The findings exhibited positive effects of short ozonation on enhancing mechanical strength, cohesion, and hydrophobicity. The prolonged ozonation of 120 min demonstrated optimal improvements in continuity, swelling, and antibacterial resistance of obtained films. Incorporating chitosan enhanced tensile performance, stiffness, and vapor barriers but increased moisture absorption. Tailoring the activation of biomass through ozone pretreatment and chitosan addition resulted in renewable films with adjustable properties to meet diverse packaging requirements, particularly for fruit protective coatings, ensuring the preservation of post-harvest quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The electrospinning technology has set off a tide and given rise to the attention of a widespread range of research territories, benefiting from the enhancement of nanofibers which made a spurt of progress. Nanofibers, continuously produced via electrospinning technology, have greater specific surface area and higher porosity and play a non-substitutable key role in many fields. Combined with the degradability and compatibility of the natural structure characteristics of polysaccharides, electrospun polysaccharide nanofiber membranes gradually infiltrate into the life field to help filter air contamination particles and water pollutants, treat wounds, keep food fresh, monitor electronic equipment, etc., thus improving the life quality. Compared with the evaluation of polysaccharide-based nanofiber membranes in a specific field, this paper comprehensively summarized the existing electrospinning technology and focused on the latest research progress about the application of polysaccharide-based nanofiber in different fields, represented by starch, chitosan, and cellulose. Finally, the benefits and defects of electrospun are discussed in brief, and the prospects for broadening the application of polysaccharide nanofiber membranes are presented for the glorious expectation dedicated to the progress of the eras., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This work deals with assessing the performance of lignin nanoparticles (LNPs) in solving the problem of using salicylic acid as an agrochemical compound, via controlling its release. LNPs, obtained from black liquor, have been used to develop new delivery systems. Gels from chelating of LNPs with chitosan or chitosan nanoparticles (Cs-NPs) in presence or absence of cationic starch are investigated to achieve this essential aim. The nanoparticles are examined by TEM, ATR-FTIR, and XRD techniques. Based on measurements of swelling, encapsulation, release profile, release kinetic modeling of salicylic acid (SA), infrared spectroscopy, thermo-gravimetric analysis and scanning electron microscope the behavior of the investigated nanocomposite gels is assessed. The results show that the SA release profile of Cs-NPs and its nanocomposite with LNPs in phosphate-buffered saline (PBS) (7.4) (51.5-69.4 %) is higher than that of the mixture of water and ethanol (34.9-50.4 %). The release profile in PBS (7.4) demonstrates a trend of prolonged SA release over a 48-hour period. Best control of the SA-release can be achieved by CsNPs-LNPs nanocomposite. Comparing the results with previous literature demonstrates the promising characteristics of these examined gel nanocomposites. The release of SA from nanocomposites is regulated by a diffusion mechanism and follows the Ritger-Peppas and Higuchi models for kinetic release., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study aims to explore the prevention of chitosan modified with a fused heterocyclic compound as a sustainable corrosion inhibitor for mild steel in 1 M HCl. Electrochemical instruments, including potentiodynamic polarization techniques, and electrochemical impedance spectroscopy (EIS), were employed to evaluate the corrosion protection performance. The outcomes showed that the chitosan modified with a fused heterocyclic compound has outstanding inhibition performance, with an inhibition effectiveness of 98.25 % at 100 ppm. The anti-corrosion features of modified chitosan were ascribed to the presence of hetero atoms in modified chitosan composite which leads to the creation of a protective layer, The modified chitosan composite behaved as mixed-typed inhibitors, as shown by the PDP results. The modified chitosan composite adsorbs on mild steel in the investigated corrosive media via chemisorption interactions, and its adsorption followed the Langmuir adsorption model. Furthermore, increasing the temperature from 303 to 333 K enhanced the corrosion rate, most likely due to the desorption of the inhibitor agent from the steel surface., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this study, the quaternized carboxymethyl chitosan (QCMCS), oxidized hyaluronic acid (OHA), 3,3'-dithiobis-(propionohydrazide) (DTP) were used as raw materials for the synthesis of hydrogels with excellent properties as carriers for drug release. The hydrogels were prepared by a simple "one-pot" method without external stimuli on the basis of interactions between formed dynamic covalent bonds (imine bonds, acylhydrazone bonds, disulfide bonds) and hydrogen bonds. The hydrogels had rapid self-healing properties, with a self-healing rate of 96 % after 30 min, as well as good pH responsiveness and excellent cytocompatibility (up to 98 % cell survival). The compressive stress of the hydrogels reached 423 kPa. Moreover, a representative drug (acetylsalicylic acid) demonstrated sustained release in the hydrogels (>72 h). The drug release behaviour was shown to be consistent with the Fick diffusion mechanism by kinetic modelling. Collectively, the findings demonstrate that the QCMCS + OHA + DTP injectable self-healing hydrogels are a potential material for the construction of pH-controlled drug delivery platforms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Using an in situ sol-gel technique, new nanoarchitectonics of propolis loaded zinc oxide nanoarchitectonics (PP/ZnO-NPs) were developed in order to improve the in vivo outcomes of collagen-chitosan gel in wounded rats. The obtained nanoarchitectonics were fully characterized. The XRD results indicate the presence of a Zincite phase for ZnO-NPs and Zincite accompanied by a minor amount of zinc hydroxide for PP/ZnO-NPs samples. While the TEM findings illustrate the transfer of the ZnO-NPs from agglomerated spheres with an average particle size of 230 ± 29 nm to needle-like NPs of 323 ± 173 nm length (PP1/ZnO-NPs) and to a sheet-like NPs of 500 ± 173 nm diameter (PP2/ZnO-NPs). In addition, the incorporation of PP results in an increase in the surface negativity of ZnO-NPs to -31.4 ± 6.4 mV for PP2/ZnO-NPs. The antimicrobial activities of the nanocomposite gel loaded with 10%PP1/ZnO-NPs (G6) revealed the highest inhibition zone against E. coli (26 ± 2.31 mm). Remarkably, the in vivo outcomes showed that the nanocomposite gel (G6) has exceptional collagen deposition, quick wound closure rates, and re-epithelization. The outcomes demonstrate the nanocomposite gel encouraging biological properties for the treatment of damaged and infected wounds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The unique features of self-healing hydrogels hold great potential for biomedical applications including injectable hydrogels for cancer treatment, procedures for tumor removal or resection. However, the fabrication of durable and multifunctional self-healing hydrogels composed of biocompatible, green building blocks via versatile synthetic methodology continues to pose a significant challenge. Here, we engineered dialdehyde cellulose (DAC, as a macromolecular bio-crosslinker), and electrosterically stabilized nanocrystalline cellulose (ENCC, as a ligand-targeted drug carrier) to facilitate a strategy for the construction of self-healing hydrogels. Benefiting from its high carboxyl group density, ENCC was functionalized with folic acid (FA) using a non-toxic DMTMM coupling agent and loaded with doxorubicin (DOX, a model drug) through electrostatic interactions. A natural self-healing hydrogel was prepared from carboxymethyl chitosan (CCTS) and DAC mixed with DOX-loaded FA-ENCC using dynamic Schiff-base and hydrogen linkages. A combination of active supramolecular and vital covalent junctions led to a soft (storage modulus ∼500 Pa) and durable material, with rapid (< 5 min) reconstruction of molecular structure from fractured and injected to intact forms. The DAC-CCTS hydrogel showed an appreciable loading capacity of ∼5 mg g -1 . Biocompatibility of the hydrogels was evaluated using cell viability and metabolic activity assays, showing lower metabolic activity due to sustained release of its cargo. These materials offer a versatile, sustainable, and green platform for the efficient construction of hydrogels, based on macro- and nano-engineered cellulose, the most abundant and easily accessible biopolymer., Competing Interests: Declaration of competing interest Ashok Kakkar reports financial support was provided by Natural Sciences and Engineering Research Council of Canada., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Acacia catechu contains polyphenolic compounds such as catechin and tannins, which exhibit antioxidant and antimicrobial properties that have the potential to be used in food packaging applications. In this study, chitosan-based (CH) antioxidant films were developed with the incorporation of calcium carbonate (CC) and Acacia catechu (CT). The films were fabricated by the solvent-casting method, and the effects of the different concentrations of Acacia catechu were analyzed. The physicomechanical, antioxidant, and UV shielding properties of the films were determined. The addition of Acacia catechu and calcium carbonate has significantly increased the tensile from 2.30 MPa to 4.95 MPa, respectively, for neat CH and CH/CC/CT-4 film. At the same time, there is a reduction in the elongation at break from 26.75 % in neat CH film to 12.11 % in CH/CC/CT-4 film. The CH/CC/CT-4 film has shown the highest ferric-reducing antioxidant power (FRAP) of 0.440 mg Trolox/g dried weight of the film and 2,2 diphenyl picrylhydrazyl (DPPH) radical scavenging activity of 93.05 %. The UV transmittance of CH/CC/CT-4 film was 0.46 %, the lowest compared to the rest of the fabricated films. These active properties depict that CH/CC/CT-4 film has the potential to be utilized for the packaging of light and oxygen-sensitive food products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

As a biomarker of oxidative stress, hydrogen peroxide (H 2 O 2 ) plays a complex role in organisms, including regulating cell signaling, respiration, the immune system, and other life processes. Therefore, it is important to develop a tool that can simply and effectively monitor H 2 O 2 levels in organisms and the environment. In this work, naphthalene fluorophores with a borate structure were introduced into chitosan (CTS) azide, and a CTS-based fluorescence sensor (CTS-HP) was designed for sensitive H 2 O 2 detection. The biocompatibility and degradability of CTS endowed CTS-HP with reduced biotoxicity compared with organic fluorescent dyes, and the substitution degree of fluorophores on the CTS chains was 0.703. The randomly coiled chain structure of the CTS-HP probe enabled the boronic acid recognition sites on the fluorophores to achieve the enrichment of analyte H 2 O 2 through a synergistic effect. Therefore, the probe CTS-HP (10 μg mL -1 ) exhibited a 21-fold fluorescence enhancement and good detection limit (LOD = 8.98 nM) in H 2 O 2 solution, reaching the maximum fluorescence response faster (within 16 min). The probe also successfully achieved the fluorescence imaging of endogenous and exogenous H 2 O 2 in zebrafish and living cells and labeled the recovery experiment of H 2 O 2 in real water samples (recoveries rates of 90.93-102.9 % and RSD < 3.09 %)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Despite the advancements in bone tissue engineering, the majority of implant failures are caused due to microbial contamination. So, efforts are being made to develop biomaterial with antimicrobial property enhancing the regeneration of damaged bone tissue. In the present study, chitosan-gelatin (CG) scaffolds containing silver-doped hydroxyapatite (AgHAP) nanoparticles at 0.5%, 1.0% and 1.5% (w/v) were fabricated by lyophilization technique. The results confirmed the synthesis of AgHAP nanoparticles and showed interconnected porous structure of the nanocomposite scaffolds with 89%-75% porosity. Similarly, the swelling percentage, degradation behavior and compressive modulus of CG-AgHAP nanocomposite scaffolds were 1666%, 40% and 0.7 MPa, respectively. The developed nanocomposite scaffolds revealed better antimicrobial properties and bioactivity. The cell culture studies showed favorable viability of Wharton's jelly stem cells on CG-AgHAP nanocomposite scaffolds. CAM (chorioallantoic membrane) assay determined the angiogenic potential with better visualization of blood vessels in the CAM area. Hence, the obtained results confirmed that CG-AgHAP 3 nanocomposite scaffold was the most suitable for bone tissue engineering applications among all scaffolds.

The toxic volatile organic compounds (VOCs), especially formaldehyde (FA), released from decoration materials pose a great threat to human health. In this study, formaldehyde adsorption performance of the specially formulated nanocellulose/chitosan aerogel (CNFCA) was investigated in simulated atmosphere. The physicochemical property of the composite aerogel was characterized, which had a large specific surface area (153.67 m 2 /g), a rough surface and an ultra-thin and porous structure. The composite aerogel showed excellent adsorption capacity for the formaldehyde, its theoretical maximum adsorption capacity was as high as 83.89 mg/g, and the adsorption process was more in accordance with the pseudo-second-order kinetics. The chromogenic reaction between the 4-amino-3-benzo-5-mercapto-1,2,4-triazolium (AHMT) and CNFCA was found that the color of the composite aerogel was depended on the free formaldehyde concentration. Based on this phenomenon, a colorimetric card was proposed and built to detection the formaldehyde in the atmosphere. Moreover, the adsorption mechanism research was found that the CNFCA with a multilayer structure belonged to physicochemical complex adsorption., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

To improve the paper strength, a number of resins and polymeric materials are being used, which is not environmental friendly and sustainable. Therefore, bio-based paper additives for the papermaking industry are essential. In this investigation, a water soluble biopolymer like carboxymethyl chitosan (CMCh) was prepared. The degree of substitution of the prepared CMCh was 2.49. The solubility of the prepared CMCh was 2.0 (w/v) % at 50 °C, and the conductivity increased with the increase of CMCh concentration in water. The prepared CMCh was applied as dry and wet strength agent of unrefined and refined softwood pulps. Both pulp increased dry and wet strength with increasing CMCh dose. An addition of 2.0 % CMCh increased dry strength by 125 % and wet strength by 293 % of unrefined pulp. On the other hand, the dry and wet tensile index of refined pulp increased from 59.48 N·m/g to 66.11 N·m/g and 2.48 N·m/g to 3.47 N·m/g, respectively, with the addition of 1.0 % CMCh. The CMCh was also used in filler modification. The precipitated calcium carbonate (PCC) modified with CMCh increased the ash content in paper with improved strength properties. The CMCh can be used in papermaking both for improving paper strength and filler retention., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Direct addition of disinfectants and membrane separation techniques have been common methods to address microbial contamination in water. However, disinfectants may generate toxic by-products, and even minor damage or biofilm formation on filtration membranes can lead to a heightened risk of microbial contamination. Consequently, how to quickly and safely disinfect microbial contaminated water sources remains a huge challenge. In this study, the high-strength broad-spectrum antibacterial CNF/CS composite membrane was fabricated by utilizing cellulose nanofibers (CNF) to reinforce the structure of chitosan (CS). The resulting CNF/CS composite membrane exhibits an impressive tensile strength of 148 MPa and boasts an active chlorine content of 5.29 %. Notably, even after undergoing 50 washing cycles and 10 repeated chlorination procedures, the structural integrity and high active chlorine content of the composite membrane remain preserved, validating its exceptional strength, stability, and chlorine rechargeability. Additionally, the CNF/CS antibacterial materials demonstrate remarkable attributes in terms of rapid sterilization, sustained and consistent release of active chlorine, and efficient inhibition of biofilm formation, demonstrating great potential in efficient, green, and safe sterilization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

The solubility of cyclodextrin metal-organic frameworks (CD-MOFs) in aqueous media making it not suitable as sustained-release drug carrier. Here, curcumin-loaded CD-MOFs (CD-MOFs-Cur) was embedded in chitosan-graft-poly(lactic acid) (CS-LA) via a solid-in-oil-in-oil (s/o/o) emulsifying solvent evaporation method forming the sustained-release composite microspheres. At CS-LA concentration of 20 mg/mL, the composite microspheres showed good sphericity. The average particle size of CS-LA/CD-MOFs-Cur (2:1), CS-LA/CD-MOFs-Cur (4:1) and CS-LA/CD-MOFs-Cur (6:1) composite microspheres was about 9.3, 12.3 and 13.5 μm, respectively. The above composite microspheres exhibited various degradation rates and curcumin release rates. Treating in HCl solution (pH 1.2) for 120 min, the average particle size of above microspheres reduced 28.19 %, 24.34 % and 6.19 %, and curcumin released 86.23 %, 78.37 % and 52.57 %, respectively. Treating in PBS (pH 7.4) for 12 h, the average particle size of above microspheres reduced 30.56 %, 26.56 % and 10.66 %, and curcumin released 68.54 %, 54.32 % and 31.25 %, respectively. Moreover, the composite microspheres had a favorable cytocompatibility, with cell viability of higher than 90 %. These composite microspheres open novel opportunity for sustained drug release of CD-MOFs., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influences our work. There is no professional or other personal interest of any nature or kind in any product., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Sugarcane bagasse-derived nanofibrillated cellulose (NFC), a type of cellulose with a fibrous structure, is potentially used in the pharmaceutical field. Regeneration of this cellulose using a green process offers a more accessible and less ordered cellulose II structure (amorphous cellulose; AmC). Furthermore, the preparation of cross-linked cellulose (NFC/AmC) provides a dual advantage by building a structural block that could exhibit distinct mechanical properties. 3D aerogel scaffolds loaded with risedronate were prepared in our study using NFC or cross-linked cellulose (NFC/AmC), then combined with different concentrations of chitosan. Results proved that the aerogel scaffolds composed of NFC and chitosan had significantly improved the mechanical properties and retarded drug release compared to all other fabricated aerogel scaffolds. The aerogel scaffolds containing the highest concentration of chitosan (SC-T3) attained the highest compressive strength and mean release time values (415 ± 41.80 kPa and 2.61 ± 0.23 h, respectively). Scanning electron microscope images proved the uniform highly porous microstructure of SC-T3 with interconnectedness. All the tested medicated as well as unmedicated aerogel scaffolds had the ability to regenerate bone as assessed using the MG-63 cell line, with the former attaining a higher effect than the latter. However, SC-T3 aerogel scaffolds possessed a lower regenerative effect than those composed of NFC only. This study highlights the promising approach of the use of biopolymers derived from agro-wastes for tissue engineering.

Hydrogen peroxide (H 2 O 2 ) acts as an important reactive oxygen species (ROS) and maintains the redox equilibrium in organisms. Imbalance of H 2 O 2 concentration is associated with the development of many diseases. Traditional small molecular based fluorescent probes often show drawbacks of cytotoxicity and easily metabolic clearance. Herein, a chitosan-based two-photon fluorescent nanoprobe (DC-BI) was constructed and applied for H 2 O 2 detection in live organisms. DC-BI was composed by chitosan nanoparticles and a two-photon fluorophore of naphthalimide analogues (BI) with H 2 O 2 -responsive property. The structure of DC-BI was characterized by NMR, FTIR, XPS, XRD, DLS and MLS analyses. As study shown, the nanoprobe DC-BI exhibited improved distribution stability and smaller cytotoxicity. In the presence of H 2 O 2 , both the absorption and emission spectra show dramatic changes, the fluorescence intensity at 580 nm obviously enhanced. Furthermore, fluorescence imaging results indicate that DC-BI is capable of imaging endogenous H 2 O 2 in cells and zebrafish. The design and development of chitosan-based nanoprobe DC-BI has provided a general example of nanoprobe construction with excellent distribution stability, two-photon property, and biocompatibility., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this study, novel crosslinked hydrogels based on chitosan (CS) and carrageenan (CRG) loaded with silver and/or copper nanoparticles (Ag/CuNPs) were prepared through a freeze-drying (thawing) process to be applied in biological applications comprising wound dressing. These hydrogels showed porous interconnected structures. The influence of the used nanoparticles (NPs) on the antibacterial properties of the CS/CRG hydrogels was explored. Antimicrobial results revealed that both CS/CRG/CuNPs, CS/CRG/AgNPs, and CS/CRG/Ag-CuNPs exhibited promising antibacterial and antifungal activity against Escherichia coli, Pseudomonas aeruginosa, Streptococcus mutans, Staphylococcus aureus, Bacillus subtilis, and Candida albicans. Moreover, CS/CRG/AgNPs, CS/CRG/CuNPs, and CS/CRG/Ag-CuNPs hydrogels showed potential antioxidant activity to be 57%, 78%, and 89%, respectively. Furthermore, cytotoxicity results against Vero normal cell line confirmed that all designed hydrogels are safe upon usage. The bimetallic CS/CRG hydrogels showed notably enhanced antibacterial properties among the as-prepared hydrogels allowing them to be a successful material upon being employed in wound dressing applications., (© 2023 Wiley-VCH GmbH.)

H 2 S is one of the signal molecules in live organisms and a poisonous gas, which is closely related to our life. The traditional synthetic small molecular organic probes often have the disadvantages of low biocompatibility. In this paper, a fluorescent nanoprobe for detecting H 2 S in live organisms was constructed based on chitosan. The structure of CH-CN was characterized by infrared spectroscopy, nuclear magnetic resonance, x-ray photoelectron spectroscopy (XPS), XRD and scanning electron microscope (SEM). In the presence of Na 2 S, the fluorescence intensity at 560 nm was significantly enhanced, and showed high selectivity and sensitivity toward H 2 S. Based on the good fluorescence response of CH-CN, the probe was also successfully applied to H 2 S imaging in HepG2 cells and zebrafish. These experimental results indicate that the probe has lower cytotoxicity and excellent stability. The present research shows a typical example of construction of chitosan-based macromolecular fluorescent materials and their bio-imaging application., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2023. Published by Elsevier B.V.)

In this study, the formation of clove essential oil loaded chitosan nanocapsules (CEO/CS-NCs) was achieved by the ionotropic gelation technology. The spherical shape and core-shell structure of CEO/CS-NCs were characterized by SEM, TEM, and FT-IR. CEO/CS-NCs have a reasonable encapsulation efficiency rate of 39 % and an average size of 253.63 nm. The simulated release of CEO/CS-NCs in a citric acid buffer solution shows that the nano-encapsulation technology could control the sustained release of clove essential oil (CEO). The shelf life of untreated blueberries at room temperature is only about 3 days, while CEO/CS-NCs combined with low-temperature storage can extend the shelf life to about 12 days. The quality characteristic of blueberries, including fruit firmness and moisture content, were effectively maintained, and the rotting rate of blueberries was significantly reduced with CEO/CS-NCs. As a natural preservative, CEO/CS-NCs have a good antioxidant activity close to the commercial antioxidant butylated hydroxytoluene (BHT) and a high antibacterial activity against pathogenic bacteria (PB) isolated from naturally occurring blueberries. Therefore, this study not only gives a theoretical basis for the development of CEO as a commercial preservative but also provides a practical solution to solve the protection challenge of preserving blueberries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Injectable hydrogels with notable mechanical properties and self-healing ability are promising carriers for use as a drug delivery system. Here, adipic acid dihydrazide (ADH) and calcium ions (Ca 2+ ) were introduced into quaternary ammonium carboxymethyl chitosan and aldehyde-modified hyaluronic acid hydrogels (QCS + OHA). The hydrogels were synthesized through the interaction of the Schiff bases (imine bonds, acylhydrazone bonds) and coordination bonds via a facile one-step approach. The gelation time (∼54 s) ensured excellent injectability. The QCS + OHA + ADH + Ca 2+ hydrogel had notable mechanical properties (compressive stress up to 896.30 KPa), good self-healing ability (up to 94 %), good pH responsiveness, and excellent antibacterial properties. In addition, the QCS + OHA + ADH + Ca 2+ hydrogel had a high drug loading capacity (121.3 mg/g) and sustained drug release behaviour (≥120 h). The results of cytotoxicity tests showed a high cell proliferation rate (up to 98 %) and good cytocompatibility. In summary, this work presents an injectable and self-healing pH-responsive hydrogel that can be used as a carrier for drug delivery systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Bacterial infection can hinder the infected wound healing process. Because of the growing drug-resistance bacteria, there is an urgent desire to develop alternative antibacterial strategies to the antibiotics. Herein, the quaternized chitosan coated CuS (CuS-QCS) nanozyme with peroxidase (POD)-like activity was developed through a facile biomineralized approach for synergistic efficient antibacterial therapy and wound healing. The CuS-QCS killed bacteria by the electrostatic bonding of positive charged QCS with bacteria and releasing Cu 2+ to damage bacterial membrane. And importantly, CuS-QCS nanozyme exhibited higher intrinsic POD-like activity, which converted H 2 O 2 with low concentration into highly toxic hydroxyl radical (OH) for the elimination of bacteria by oxidative stress. Through cooperation of POD-like activity, Cu 2+ and QCS, CuS-QCS nanozyme exhibited excellent antibacterial efficacy of approximate 99.9 % against E. coli and S. aureus in vitro. In addition, the QCS-CuS was successfully used to promote the healing of S. aureus infected wound with good biocompatibility. This synergistic nanoplatform presented here shows great potential applications in the field of wound infection management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

The hemorrhage in daily life was a great challenge for the life health. Before hospitalization and infection, stopping traumatic bleeding timely is an important measure to decrease the death threat. The high crystallinity and low porous structure of chitin (CH) make texture of sole CH sponge not soft enough, which limit its hemostatic properties. In this work, loose corn stalk (CS) was used to modify the structures and properties of sole CH sponge. The novel hemostatic composite sponge of CH/CS4 was prepared by cross-linking and freeze-drying process of chitin and corn stalk suspension. The composite sponge obtained best physical and hemostatic properties at the 1:1 volume ratio of chitin and corn stalk. Thanks to the porous structures, CH/CS4 possessed high water/blood absorption ability (34 ± 2 g/g and 32.7 ± 2 g/g), rapid hemostatic time (31 s) and low blood loss (0.31 g), allowing it to be delivered into the wound bleeding sites to reduce the wound bleeding by robust physical barrier and pressure effect. Furthermore, CH/CS4 displayed excellent hemostatic performance than sole CH and commercial polyvinyl fluoride sponge (PVF). Moreover, CH/CS4 displayed superior wound healing ability and cytocompatibility. Therefore, the CH/CS4 has high potential application in medical hemostatic field., Competing Interests: Declaration of competing interest The authors declare no competing financial interests and any non-financial competing interests., (Copyright © 2023. Published by Elsevier B.V.)

Natural polysaccharides show enviable advantages for preparation of sustainable hybrid materials. However, in most cases, complex chemical modifications of natural polysaccharides are required, which not only causes changes of the inherent properties of polysaccharides, but also increases the manufacturing costs of the final materials. Therefore, it is highly desired to develop efficient and low-cost ways to access polysaccharides-containing hybrid materials. In this work, we report the environmentally friendly preparation of a new kind of polysaccharide-based materials, called polysaccharide-vitrimer hybrid materials, for the first time. The vitrimer synthesis and hybridization with polysaccharides can be achieved via a convenient one-pot method in absence of solvent and catalyst. In addition, time-consuming and labor-intensive physical/chemical modifications of natural polysaccharides are completely avoided. The resultant hybrid materials show good mechanical performance (tensile toughness is up to 13.7 MJ/m 3 ), high thermal stability (T d,max is up to 457 °C), fast self-healing ability (self-healing efficiency is up to 99 % within 20s at 80 °C) and excellent reprocessability and recyclability (at least three cycles). Especially, conductive polysaccharide-vitrimer hybrid materials could be readily prepared from the resultant materials, exhibiting novel applications as flexible sensors and electromagnetic shielding materials (the EMI SE is up to 24.93 dB)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Using environmentally friendly biomaterials in different aspects of human life has been considered extensively. In this respect, different biomaterials have been identified and different applications have been found for them. Currently, chitosan, the well-known derivative of the second most abundant polysaccharide in the nature (i.e., chitin), has been receiving a lot of attention. This unique biomaterial can be defined as a renewable, high cationic charge density, antibacterial, biodegradable, biocompatible, non-toxic biomaterial with high compatibility with cellulose structure, where it can be used in different applications. This review takes a deep and comprehensive look at chitosan and its derivative applications in different aspects of papermaking., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Biocompatible coatings that can protect metal implants have great potential in tissue engineering. In this work, MWCNT/chitosan composite coatings with hydrophobic-hydrophilic asymmetric wettability were facilely prepared by one-step in situ electrodeposition. The resultant composite coating exhibits excellent thermal stability and mechanical strength (0.76 MPa), benefiting from the compact internal structure. The thickness of the coating can be controlled precisely by the amounts of transferred charges. The MWCNT/chitosan composite coating demonstrates a lower corrosion rate due to its hydrophobicity and compact internal structure. Compared with exposed 316 L stainless steel, its corrosion rate is reduced by two orders of magnitude from 3.004 × 10 -1 mm/yr to 5.361 × 10 -3 mm/yr. The content of iron released from 316 L stainless steel into the simulated body fluid drops to 0.1 mg/L under the protection of the composite coating. In addition, the composite coating enables efficient calcium enrichment from simulated body fluids and promotes the formation of bioapatite layers on the coating surface. This study contributes to furthering the practical application of chitosan-based coatings in implant anticorrosion., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Cell-free and cell-loaded constructs are used to bridge the critical-sized bone defect. Oxidative stress at the site of the bone defects is a major interference that slows bone healing. Recently, there has been an increase in interest in enhancing the properties of three-dimensional scaffolds with free radical scavenging materials. Cerium oxide nanoparticles (CNPs) can scavenge free radicals due to their redox-modulating property. In this study, freeze-drying was used to fabricate CG-CNPs nanocomposite scaffolds using gelatin (G), chitosan (C), and cerium oxide nanoparticles. Physico-chemical, mechanical, and biological characterization of CG-CNPs scaffolds were studied. CG-CNPs scaffolds demonstrated better results in terms of physicochemical, mechanical, and biological properties as compared to CG-scaffold. CG-CNPs scaffolds were cyto-friendly to MC3T3-E1 cells studied by performing in-vitro and in-ovo studies. The scaffold's antimicrobial study revealed high inhibition zones against Gram-positive and Gram-negative bacteria. With 79 % porosity, 45.99 % weight loss, 178.25 kPa compressive modulus, and 1.83 Ca/P ratio, the CG-CNP 2 scaffold displays the best characteristics. As a result, the CG-CNP 2 scaffolds are highly biocompatible and could be applied to repair bone defects., Competing Interests: Declaration of competing interest The authors have no conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Bacterial cellulose (BC) lithium-ion batteries separators possess outstanding thermal dimensional stability and electrolyte wettability, but theirs nano diameter and high aspect ratio lead to poor porosity and pore size uniformity of dense BC separators, limiting the Li + transmission in the separators. In this paper, chitosan (CS) with different molecular weight was grafted onto BC (named OBCS), and a high-performance OBCS separator with excellent pore structure and tunable pore size was prepared by simple suction filtration. The spacing and dispersion uniformity of OBCS were improved by the CS grafted on BC surface, thus improving the pore structure and porosity of OBCS separators. The results showed that the obtained OBCS separators not only have excellent physicochemical properties, but also exhibit higher electrochemical performances than the commercial polypropylene (PP) separator. This work provides a new feasible strategy for improving the pore structure and porosity of nanocellulose separators., Competing Interests: Declaration of competing interest There are no conflicts of interest to declare in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Modified magnetite chitosan with silver nanoparticles was synthesized and tested for removing cationic and anionic dyes in aqueous solutions. Initial dye concentration, pH, and contact time were examined. Results showed that pH (4.0) was optimal for removing anionic dyes (methyl orange) and pH 8.0 for removing cationic dyes (methylene blue). According to these results, zeta potentials were found to be 8.43 and - 39.17 mV at pH 4.0 and 8.0, respectively. So, it is attracted to positively charged cationic dyes in an alkaline medium and negatively charged anionic dyes in an acidic medium because of their opposite charges. Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), thermal gravimetric analysis (TGA), and zeta potential measurements were used to characterize the synthesized nanosorbents. A pseudo-second-order kinetic model is fitted with the Langmuir adsorption model, with an adsorption capacity of 417 and 476 mg/g for methyl orange and methylene blue, respectively. For both dyes, modified magnetite chitosan with silver nanoparticles showed high regeneration capability and recovery for up to four cycles without adsorption efficiency loss. Furthermore, modified magnetite chitosan with silver nanoparticles, as prepared in the present study, was demonstrated to be an effective adsorbent for organic pollutants in wastewater., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2022. Published by Elsevier B.V.)

The development of eco-friendly, sustainable, biodegradable, and biocompatible green biopolymer composites is becoming increasingly important. In this study, acetoacetylated lignin (ATL) was obtained via an eco-friendly, facile one-step synthesis reaction, and chitosan (CS)-containing ATL films (CSL) were prepared. The chemical structural analysis of ATL confirmed that the acetoacetyl groups were successfully grafted onto kraft lignin (KL). ATL with adequate acetoacetyl groups exhibited enhanced molecular weight and antioxidant and ultraviolet (UV)-shielding properties. In particular, ATL, with a half maximal inhibitory concentration (IC 50 ) of 23.8 μg·mL -1 , exhibited superior antioxidant activity than butylated hydroxytoluene (38.3 μg·mL -1 ) and KL (50.0 μg·mL -1 ). When ATL was incorporated into the CS solution to prepare biofilms, the antioxidant activity, UV-shielding property, water resistance, and thermal stability of the CSL greatly improved. Notably, the UV-A and UV-B shielding properties of the 2 % CSL were 130 % and 78 % higher than those of the pure CS film, respectively. Therefore, ATL designed with lignin-derived multifunctional properties has potential applications as an antioxidant and UV-shielding bio-additive and shows significant prospects in food packaging and biomedical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Novel phase change materials composed of polyethylene glycol (PEG), cellulose nanofibers (CNFs) and carbon nanotubes (CNTs) were developed by an efficient and environment friendly strategy. The CNFs were modified and cross-linked by chitosan to form three-dimensional network structure, which provides strong support for the resulting CNF/CNT/PEG composites. The structure and properties of CNF/CNT/PEG composites were characterized using scanning electron microscopy, spectrums, and differential scanning calorimeter. They exhibit high latent heat (158.3 J/g), low heat loss (0.75%) and excellent photo-thermal conversion (energy storage efficiency 85.6%), electro-thermal conversion (energy storage efficiency 92.3%) properties. Due to their excellent performances, CNF/CNT/PEG composites have great potential to be used as thermal management materials., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Amoxicillin (AMX) is a widely used antibiotic, which induces harmful effects to nature via bioaccumulation and persistence in the environment if discharged untreated into water bodies. In the current study, a novel bionanocomposite, bismuth oxyiodide-chitosan (BiOI-Ch), was synthesized by a facile precipitation method and its amoxicillin (AMX) adsorption capacity in the presence of ultrasonic waves has been explored. Multiple batch experiments were performed to achieve the optimum operational parameters for maximum adsorption of AMX and the obtained results were as follows: pH 3, 80 mg g -1 AMX concentration, 1.7 g L -1 adsorbent dose, temperature 298 K and ultrasonication time 20 min. Composite removed approximately 90% AMX from the solution under optimized conditions, while the maximal adsorption capacity was determined to be 81.01 mg g -1 . BiOI-Ch exhibited superior adsorption capacity as compared to pure BiOI (33.78 mg g -1 ). To understand the dynamics of reaction, several kinetic and isotherm models were also examined. The adsorption process obeyed pseudo-second-order kinetic model (R 2  = 0.98) and was well fitted to Freundlich isotherm (R 2  = 0.99). The addition of biowaste chitosan to non-toxic bismuth-based nanoparticles coupled with ultrasonication led to enhanced functional groups as well as surface area of the nanocomposite resulting in superior adsorption capacity, fast adsorption kinetics and improved mass transfer for the removal of AMX molecules. Thus, this study demonstrates the synergistic effect of ultrasonication in improved performance of novel BiOI-Ch for potential application in the elimination of persistent and detrimental pollutants from industrial effluent after necessary optimization for large-scale operation., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

We report herein the dielectric properties response of two ionic chitosan derivatives. More specifically, we report here chitosan derivatives bearing guanidinium groups, prepared through the reaction between chitosan and cyanamide when scandium (III) triflate is present. The anionic counter ions of the guanidinium groups could be changed by working either in acetic acid or hydrochloric acid. In this way, two chitosan derivatives, namely N-guanidinium chitosan acetate (GChAc) and N-guanidinium chitosan chloride (GChCl), were produced. The materials were investigated by 13 C solid state NMR, FT-IR spectroscopy, SEM and TEM analysis and compared with the parent chitosan. Dielectric spectroscopy has been used to study the relaxation behavior of the parent chitosan and the new chitosan derivatives over wide ranges of temperature and frequency, indicating that local motion is affected by counter ions. Due to these features, these materials are interesting candidates as high-power electrical materials for green technological applications., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The promising features of most bacterial celluloses (BC) promote the continuous mining for a cost-effective production approach toward wide and sustainable applications. Herein, cantaloupe peels (CP) were successfully implemented for sustainable BC production. Results indicated that the enzymatically hydrolyzed CP supported the maximum BC production of approximately 3.49 g/L when used as a sole fermentation media. The produced BC was fabricated with polyvinyl alcohol (PVA) and chitosan (Ch), and loaded with green synthesized copper oxide nanoparticles (CuO-NPs) to improve its biological activity. The novel composite showed an antimicrobial activity against several human pathogens such as Staphylococcus aureus, Streptococcus mutans, Salmonella typhimurium, Escherichia coli, and Pseudomonas fluorescens. Furthermore, the new composite revealed a significant in vitro anticancer activity against colon (Caco-2), hepatocellular (HepG-2), and breast (MDA) cancer cells, with low IC 50 of 0.48, 0.27, and 0.33 mg/mL for the three cell lines, respectively. On the other hand, the new composite was remarkably safe for human skin fibroblast (HSF) with IC 50 of 1.08 mg/mL. Interestingly, the composite membranes exhibited lethal effects against all stages of larval instar and pupal stage compared with the control. In this study, we first report the diverse potential applications of BC/PVA/Ch/CuO-NPs composites based on green synthesized CuO-NPs and sustainably produced BC membrane., (© 2022. The Author(s).)

Recent breakthroughs in the field of nanoparticle-based therapeutic delivery methods have changed the standpoint of cancer therapy by effectively delaying the process of disease development. Nanoparticles have a unique capacity of good penetrating ability than other therapeutic leads used in traditional therapeutics, and also, they have the highest impact on disease management. In the current study isolongifolene-loaded Chitosan nanoparticles have been formulated, synthesized and then characterized by the use of Fourier Transform Infrared Spectroscopy, X-ray Diffraction, Scanning Electron Microscopy and Transmission Electron Microscopy. Further, the characterized chitosan nano formulation was evaluated for hemocompatibility, plasma stability, and in-vitro release. Isolongifolene-loaded chitosan nanoparticles were found to be compatible with plasma and also, they exhibited a constant release pattern. Hence, chitosan-loaded nanoparticles could be employed as an excellent adjuvant in cancer therapeutic, to combat the multi-drug resistance in solid tumors., (© 2022. The Author(s).)

Chitosan is a natural polymer with acceptable biocompatibility, biodegradability, and mechanical stability; hence, it has been widely appraised for drug and gene delivery applications. However, there has been no comprehensive assessment to tailor-make chitosan cross-linkers of various types and functionalities as well as complex chitosan-based semi- and full-interpenetrating networks for drug delivery systems (DDSs). Herein, various fabrication methods developed for chitosan hydrogels are deliberated, including chitosan crosslinking with and without diverse cross-linkers. Tripolyphosphate, genipin and multi-functional aldehydes, carboxylic acids, and epoxides are common cross-linkers used in developing biomedical chitosan for DDSs. Methods deployed for modifying the properties and performance of chitosan hydrogels, via their composite production (semi- and full-interpenetrating networks), are also cogitated here. In addition, recent advances in the fabrication of advanced chitosan hydrogels for drug delivery applications such as oral drug delivery, transdermal drug delivery, and cancer therapy are discussed. Lastly, thoughts on what is needed for the chitosan field to continue to grow is also debated in this comprehensive review article., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The increasing environmental burden generated by disposable plastic wastes makes the development of sustainable substitute materials an emergent task. As one of the most abundant bioresources, chitosan (CS) has been considered as a potential candidate for plastic substitution. Conventionally, CS-based materials are fabricated through a solution-processing procedure due to the high crystallinity of CS. Herein, we designed a CS-based material via integrating CS into the network of polyimine (PI), which shows thermomechanical processability similar to plastics. Strong interactions were achieved through dynamic imine bond and hydrogen bond and thus formed a thermo-processable dynamic composite network. These CS-based plastic substitutes exhibit exceptional mechanical performances, excellent thermal/chemical stability, and a series of self-adaptiveness, including re-healing, reprocessing and multi-layer laminating. Notably, CPs can be easily degraded and 100% recycled for the production of next-generation materials. This work provides an alternative route to produce green and sustainable biomass materials as a plastic substitute., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The application of green and sustainable anticorrosive coatings is becoming of upsurge interest for the protection of metallic materials in aggressive environments. Herein, a stable crystalline chitosan/gum Arabic composite (CGAC) nanopowder was successfully synthesized and characterized by various methods. The CGAC nanopowder with different doses (25, 50, 100, and 200 ppm) was used to coat mild steel samples and examined its anticorrosion ability in 3.5 wt.% NaCl solution using gravimetric, electrochemical measurements, and surface characterization techniques. All methods yielded consistent results revealing that nanocomposite coatings can impart good anticorrosive properties to the steel substrate. The obtained protection efficiency was enhanced with increasing CGAC dose in the applied surface layer achieving 96.6% for the 200 ppm-coating. SEM and AFM surface morphologies of uncoated and coated samples after the inundation in the saline solution showed that CGAC coating can block the active corrosive sites on the steel surface, and prevent the aggressive Cl - ions from attacking the metallic substrate. The water droplet contact angle gave further support as it increased from 50.7° for the pristine uncoated surface to 101.2° for the coated one. The current research demonstrates a promising natural and reliable nanocomposite coating for protecting mild steel structures in the marine environment., (© 2022. The Author(s).)

Paper products are widely used in daily life, while the lack of antibacterial activity has made them become some disease transmission media. Herein, we introduced NIR-responsive molybdenum disulfide nanosheets (MoS 2 ) to endow nanocellulose paper antibacterial activity by electrostatic self-assembly with quaternized chitosan (QCS). Firstly, the MoS 2 nanosheets were exfoliated and stabilized with QCS under ultrasonication. The strong coordination between QCS and MoS 2 as well as the electrostatic attraction between QCS and cellulose nanofiber (CNF) helped to fabricate the MoS 2 @QCS/CNF composite paper. The MoS 2 @QCS/CNF composite paper exhibited excellent photothermal and photodynamic activity, achieving over 99.9% antibacterial efficacy against both E. coli and S. aureus, respectively. The hyperthermia induced by MoS 2 accelerated the glutathione (GSH) consumption and the reactive oxygen species (ROS)-independent oxidative stress destroyed the bacteria membranes integrity, synergistically leading to the malondialdehyde (MDA) oxidation and protein leakage to inhibit the bacteria growth. Importantly, the self-assembled fibrous network incorporating with the photo-stable antibacterial MoS 2 enabled the flexible composite paper with excellent mechanical strength and recyclability for long-term antimicrobial, possessing over 99.9% inhibition even after five cycles. No cell cytotoxicity was observed for the MoS 2 @QCS/CNF composite paper, suggesting the potential of composite paper for bacterial infection control., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The human digestive and absorption system has a specific pH environment, which makes it difficult to for accurate drug-release. Zwitterionic hydrogel, as a kind of drug carrier, is a feasible response strategy. In this work, a facile method was employed to prepare a series zwitterionic hydrogels composed of BC and chitosan. The composite gels could in-situ formed via Schiff's base reaction between partially oxidated bacterial cellulose and chitosan which exhibited relatively well mechanical properties. Besides, the rich amino and carboxyl groups endowed the hydrogels with excellent pH responsive performance. The minimum swelling rate of the hydrogels appeared at pH 3.5-pH 5.0. In lower or higher pH solutions, the swelling rate was greatly increased. The drug (naproxen) loading of the hydrogels was above 110 mg/g. The release amount of naproxen in the simulated gastric juice was less than intestinal fluid with the sustained release time exceeded 24 h. Through kinetic simulation analysis, the drug release behavior is in accordance with zero-order release model. Such kind of composite hydrogel is suggested to be a potential drug carrier for clinical therapy., (Copyright © 2022 Elsevier B.V. All rights reserved.)

For the high-valued utilization of hemicelluloses and for realizing the controllable synthesis of NPs, this paper's aim is to combine xylan, chitosan and nanometal materials at the same time. In this research study, firstly, propargyl xylan was synthesized via nucleophilic substitution reaction between xylan and propargyl bromide in NaOH solution. On the other hand, a tosyl group was introduced onto the 6th position of synthesized quaternized chitosan (QCS), and the azide group replaced the tosyl group to obtain 6-amido-QCS (QCS-N 3 ). The synthesis conditions of the above reactions were optimized. Subsequently, the novel xylan-click-QCS polymer was obtained via click reaction between terminal alkyne groups on the xylan chains and azide groups on QCS. Then, AgNPs and AuNPs were synthesized by adopting the xylan-click-QCS polymer as the reducing and stabilizing agent, and the reaction conditions were optimized to obtain well-dispersed and highly stable nanoparticles. There were two kinds of Ag nanomaterials, with diameters of 10~20 nm and 2~5 nm, respectively, indicating the formation of Ag nanoclusters, except for Ag nanoparticles, in this reaction. The diameter of the synthesized AuNPs was 20~30 nm, which possessed a more uniform size distribution. The Ag nanoclusters with a smaller size (2~5 nm) could inhibit MCF-7 cell proliferation effectively, indicating their application potential in cancer therapy. The study gives a new approach to the high-value utilization of biopolymers.

Novel and sustainable chitosan (CS)/activated charcoal (AC) composites were prepared by cross-linking with epichlorohydrin (ECH) to form a porous structure. Different titanium dioxide nanoparticle (TiO 2 NPs) concentrations (0, 0.2, 0.4, and 0.8% w/w) were added to enhance the photocatalytic, antibacterial, larvicidal, and pupicidal activities' efficiency toward Rose Bengal (RB) dye and the Culex pipiens. The composites were characterized by FT-IR, XRD, XPS, BET and SEM. The SEM images revealed the porous structure of CS/AC and TiO 2 nanoparticles were uniformly distributed in the CS/AC matrix. The degradation of RB dye was used to test the photocatalytic behavior of the composites. Supporting TiO 2 on a CS/AC matrix resulted in a significant increase in photocatalytic performance. The antibacterial activities supported by CS/AC/TiO 2 NPs were evaluated by bacterial growth inhibition against B. subtilis, S. aureus, E. coli, and P. aeruginosa. The results showed that CS/AC/TiO 2 NPs composite has an inhibitory effect and therefore considered antibacterial agents. CS/AC/0.4%TiO 2 NPs showed maximum efficacy against larvicidal activity and pupicidal of mosquito vector which recorded 99.00 ± 1.14, 95.00 ± 1.43, and 92.20 ± 2.64 for the first, second, and third larval instars and 66.00 ± 2.39 for pupal mortality, while the repellent activity reported high protection at 82.95 ± 2.99 with 3.24 mg/cm 2 dose compared to control DEET., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Bio-inspired borate cross-linked pulp foam (PF) with high porosity and low density can be widely used in many fields. However, PF is flammable, and lack of mechanical strength and antibacterial activity. To solve these issues, an ultra-strong PF was prepared by incorporation of chitosan and cationic polyacrylamide (CPAM). Results showed that the obtained PF exhibited highly improved mechanical properties (the compressive strength (485 kPa at a strain of 50%) was over 6 times higher compared with the borate cross-linked PF without chitosan and CPAM, and it was even higher than most of the reported cellulose-based porous materials). Also, the prepared PF has good performance on fire-retardance (hard to light), thermal insulation, antibiosis and sound absorption, due to the synergistic actions of borate, chitosan and CPAM. Additionally, spent liquor in preparing PF could be fully recycled, and thus this sustainable approach has potential for large-scale production of high-performance PF., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

In this study, cotton fabrics based on zinc oxide nanoparticles in situ synthesis, acyclovir, nanochitosan, and clove oil were treated. The treated cotton fabrics were examined by FTIR, HR-TEM, FE-SEM, EDAX, and the surface roughness processing of FE-SEM images. The obtained characterization data emphasized the nano-size of nanocomposite with high homogeneity of particles in spherical shape as well as affirmed the deposition of nanocomposite onto the textile fibers with concluded that the deposition of nanocomposite was increased parallel with sonication time. Antimicrobial and antiviral activities of treated cotton fabrics were evaluated. Results revealed that treated cotton fabrics exhibited promising antibacterial activity toward Gram-positive higher than Gram-negative bacteria. Likewise, treated cotton fabrics are still effective as antibacterial after washing for 100 cycles. Moreover, treated cotton fabrics exhibited potential antifungal activity against Candida albicans, Aspergillus niger, and Aspergillus fumigatus. The antiviral activity significantly depended on the type of virus. The treated cotton fabrics showed antiviral activity against tested viral particles (HSV-1, Adeno, and CoxB2) with viral inhibition of 95.9, 76.4, and 86.9% respectively, while in the case of coated cotton textile with acyclovir, it only exhibited viral inhibition of 49.9, 41, and 22.3% respectively., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Biopolymers are promising candidates that can be fabricated into hydrophilic matrices and used for many applications due to their distinctive properties such as non-toxic, biodegradable, biocompatibility, and low cost. A promising composite of chitosan and carrageenan with self-crosslinking has been prepared., Methods and Results: In this study, a rigorous approach for an inexpensive and non-toxic combination of different amounts of clove oil with two polyelectrolytes including chitosan and carrageenan in the form of beads has been prepared. The structure and the surface morphology of the beads were investigated using FTIR, X-ray diffraction (XRD), and SEM. Moreover, antimicrobial, antiviral activity, and molecular docking were evaluated. Antibacterial results revealed that chitosan/carrageenan@clove oil beads have antimicrobial activity as well as chitosan/carrageenan without clove oil against Escherichia coli AATCC25922, Pseudomonas aeruginosa AATCC27853, Staphylococcus aureus ATCC25923, Bacillus subtilis AATCC6051, and Candida albicans ATCC90028. Furthermore, maximum non-toxic concentration (MNTC) of chitosan/carrageenan@clove oil beads was (31.25 μg ml -1 ) which exhibited promising antiviral activity against Herpes simplex virus-1 (HSV-1), and was significantly higher than chitosan/carrageenan without clove oil, where antiviral activity was 82.94% and 57.64%, respectively. Eventually, docking study and computational calculation have been used to show the reactivity of the molecules., Conclusions: The developed chitosan/carrageenan@clove oil beads have shown promising properties to be used as carriers of drug delivery, tissue engineering, and regenerative medicine., (© 2021 Wiley-VCH GmbH.)

In this present work, a new design for antimicrobial wound bandages is presented. The wound dressings were prepared using cotton fibers reinforced with elastic compression straps and secured with a polyester fabric of tight mesh size. The cotton pads were doped with a wound healing biocomposite, composed of chitosan, glycogen, and ZnO nanoparticles (CG@ZnONPs) previously formulated through a green process. The size of ZnONPs in the prepared CG@ZnONPs was 30-80 nm. The cotton pads impregnated with the CG@ZnONPs nanocomposite were characterized using FTIR, SEM, EDX, TGA, and DTGA methods. Moreover, the prepared dressings were tested on a number of intentionally injured rats. In this experiment, the % contraction of the treated wounds was monitored and compared to that of a control group of wounded rats, to which only sterile gauzes were applied. The results showed a much faster and an almost complete healing of rats treated with the synthesized dressings and the results were further confirmed by histopathological examination. The dressings were also found to exert a significant antimicrobial activity against a number of pathogenic microorganisms, generally encountered in common wounds, and could therefore be recommended to be a novel biomedical application for a fast, successful, and flawless wounds healing process., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This study aimed to develop a plasticized starch (PS) based film loaded with chitosan nanoparticles (CNPs, 1, 2, 3, and 4%) as a reinforcing and antibacterial agent. We examined the morphology, biodegradability, mechanical, thermo-mechanical, and barrier properties of the PS/CNPs films. The antimicrobial activity against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria was investigated by colony forming unit (CFU) and disc diffusion methods. A dense structure was obtained for all PS/CNPs films and, thus, their complete biodegradation occurred in more days than neat PS. The increase in the CNPs percentage led to improved mechanical behaviour and barrier properties. PS-CNPs composite films revealed inhibition zones against both E. coli and S. aureus, with the 100% reduction in CFU against S. aureus. The current study exhibited that PS-CNPs films were more effective in inhibiting bacteria growth than neat PS film, confirming the composite films potential application as antimicrobial food packaging., (Copyright © 2021 Elsevier B.V. All rights reserved.)