Modification Of Chitosan Research Articles

Hyaluronan/B12-chitosan polyelectrolyte complex for oral colistin administration

Polyelectrolyte complexes (PECs) based on polysaccharides, including hyaluronic acid (HA) and chitosan (CS), are promising delivery systems for antimicrobial agents, including oral administration of the peptide antibiotic colistin (CT). Modification of CS with different targeting ligands to improve intestinal permeability is a suitable way to improve the oral bioavailability of polyelectrolyte particles. This study describes the procedure for obtaining CT-containing PECs based on HA and CS modified with cyanocobalamin (vitamin B12). In this case, vitamin B12 is used as a targeting ligand because it is absorbed in the ileum via specific transporter proteins. The resulting PECs had a hydrodynamic size of about 284 nm and a positive ζ-potential of about 26 mV; the encapsulation efficiency was 88.2 % and the CT content was 42.2 μg/mg. The developed systems provided a two-phase drug release: about 50 % of the CT was released in 0.5–1 h, and about 60 % of the antibiotic was cumulatively released in 5 h. The antimicrobial activity of encapsulated CT was maintained at the same level as the pure drug for at least 24 h (minimum inhibitory concentration against Pseudomonas aeruginosa was 2 μg/mL for both). In addition, the apparent permeability coefficient of CT in the PEC formulation was 2.4 × 10−6 cm/s. Thus, the incorporation of CT into HA- and vitamin B12-modified CS-based PECs can be considered as a simple and convenient method to improve the oral delivery of CT.

Periodontium-Mimicking, Multifunctional Biomass-Based Hydrogel Promotes Full-Course Socket Healing.

Preserving stable tooth-periodontal tissue integration is vital for maintaining alveolar bone stability under physiological conditions. However, tooth extraction compromises this integration and impedes socket healing. Therefore, it becomes crucial to provide early stage coverage of the socket to promote optimal healing. Drawing inspiration from the periodontium, we have developed a quaternized methacryloyl chitosan/dopamine-grafted oxidized sodium alginate hydrogel, termed the quaternized methacryloyl chitosan/dopamine-grafted oxidized sodium alginate hydrogel (QDL hydrogel). Through blue-light-induced cross-linking, the QDL hydrogel serves as a comprehensive wound dressing for socket healing. The QDL hydrogel exhibits remarkable efficacy in closing irregular tooth extraction wounds. Its favorable mechanical properties, flexible formability, and strong adhesion are achieved through modifications of chitosan and sodium alginate derived from biomass sources. Moreover, the QDL hydrogel demonstrates a superior hemostatic ability, facilitating swift blood clot formation. Additionally, the inherent antibacterial properties of the QDL hydrogel effectively inhibit oral microorganisms. Furthermore, the QDL hydrogel promotes angiogenesis, which facilitates the nutrient supply for subsequent tissue regeneration. Notably, the hydrogel accelerates socket healing by upregulating the expression of genes associated with wound healing. In conclusion, the periodontium-mimicking multifunctional hydrogel exhibits significant potential as a clinical tooth extraction wound dressing.

Chitosan‑iodine complexes: Preparation, characterization, and antibacterial activity

Bacterial infections have always been a major threat to public health, and the development of effective antibacterial substances from natural polymers is crucial. 2-Aminoisonicotinic acid (AN) was grafted onto chitosan by 1-ethyl-(3-dimethylaminopropyl)carbodiimide-mediated coupling reactions, and then modified chitosan‑iodine (CSAN-I) complexes were prepared by solvent-assisted grinding. The samples were characterized using ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, proton nuclear magnetic resonance spectroscopy, and X-ray diffraction, confirming that CSAN-I complexes had been successfully prepared. Thermogravimetric (TG) analysis indicated that the chemical modification of chitosan and iodine complexation reduced the thermal stability; X-ray photoelectron spectroscopy (XPS) analysis revealed that 81 % of the iodine in CSAN-I complex was in the form of triiodide ions. The iodine contents of three CSAN-I complexes (CSAN-I-1, CSAN-I-2 and CSAN-I-3) were 1.59 ± 0.22 %, 3.18 ± 0.26 %, and 5.56 ± 0.41 %, respectively. The antibacterial effects were evaluated in vitro, and the results indicated that CSAN-I complexes had strong antibacterial activities against both E. coli and S. aureus. In particular, CSAN-I-3 exhibited the best antibacterial effect. In addition, CSAN-I-3 was nontoxic to L929 cells with good cytocompatibility. Therefore, CSAN-I complexes can be considered as promising candidates for wound management in clinical applications.

Harnessing the power of polyethyleneimine in modifying chitosan surfaces for efficient anion dyes and hexavalent chromium removal

In this investigation, synthesis of a surface-functionalized chitosan known as amino-rich chitosan (ARCH) was achieved by successful modification of chitosan by polyethyleneimine (PEI). The synthesized ARCH was characterized by a specific surface area of 8.35 m2 g−1 and a microporous structure, with pore sizes predominantly under 25 nm. The Zeta potential of ARCH maintained a strong positive charge across a wide pH range of 3–11. These characteristics contribute to its high adsorption efficiency in aqueous solutions, demonstrated by its application in removing various anionic dyes, including erioglaucine disodium salt (EDS), methyl orange (MO), amaranth (ART), tartrazine (TTZ), and hexavalent chromium ions (Cr(VI)). The adsorption capacities (Qe) for these contaminants were measured at 1301.15 mg g−1 for EDS, 1025.45 mg g−1 for MO, 940.72 mg g−1 for ART, 732.96 mg g−1 for TTZ, and 350.15 mg g−1 for Cr(VI). A significant observation was the rapid attainment of adsorption equilibrium, occurring within 10 min for ARCH. The adsorption behavior was well-described by the Pseudo-second-order and Langmuir models. Thermodynamic studies indicated that the adsorption process is spontaneous and endothermic in nature. Additionally, an increase in temperature was found to enhance the adsorption capacity of ARCH. The material demonstrated robust stability and selective adsorption capabilities in varied conditions, including different organic compounds, pH environments, sodium salt presence, and in the face of interfering ions. After five cycles of adsorption, ARCH maintained about 60% of its initial adsorption capacity. Due to its efficient adsorption performance, simple synthesis process, low biological toxicity, and cost-effectiveness, ARCH is a promising candidate for future water treatment technologies.

Chitosan modified magnetic nanocomposite for biofilm destruction and precise photothermal/photodynamic therapy

Getting rid of the biofilms is a major challenge when treating skin and soft tissue infections (SSTI), an inflammatory illness brought on by bacteria. Traditional magnetic materials have a limited dispersibility and a biofilm permeable property, making it challenging to remove biofilms and causing infection to linger. To solve these problems, we developed a kind of magnetic composite nanoplatform coated with indocyanine green carbon dots and modified with chitosan modification (Fe-ICGCDs@CS). Fe-ICGCDs@CS has high dispersibility and improves the conductivity of biofilms under magnetic action. Fe-ICGCDs@CS can adsorb bacteria via the positive charge and achieve precise photothermal sterilization and photodynamic therapy (PDT). Moreover, by catalyzing hydrogen peroxide (2 mM), Fe-ICGCDs@CS can produce oxygen to relieve the anoxic state in the deep layer of biofilms and activate dormant bacteria to make them sensitive to external stimuli. All in all, unlike the common “just kill” sterilization model, Fe-ICGCDs@CS can accurately kill bacteria and be recovered by an external magnetic field at the end of treatment, thus reducing the potential biological toxicity of nanomaterials. Therefore, the proposed Fe-ICGCDs@CS provides a new antibacterial method with low biotoxicity for clinical application in the treatment of biofilm infections.

Exploring the antimicrobial potential of chitosan nanoparticles: synthesis, characterization and impact on Pseudomonas aeruginosa virulence factors.

The escalating antibiotic resistance observed in bacteria poses a significant threat to society, with the global prevalence of resistant strains of Pseudomonas aeruginosa on the rise. Addressing this challenge necessitates exploring strategies that would complement existing antimicrobial agents, e.g. by substances mitigating bacterial virulence without eliciting selective pressure for resistance emergence. In this respect, free-form chitosan has demonstrated promising efficacy, prompting our investigation into reinforcing its effects through nanoparticle formulations. Our study focuses on the preparation of chitosan nanoparticles under suitable conditions while emphasizing the challenges associated with stability that can affect biological activity. These challenges are mitigated by introducing quaternized chitosan, which ensures colloidal stability in the culture media. Our approach led to the production of trimethylchitosan nanoparticles with a median size of 103 nm, circularity of 0.967, and a charge of 14.9 ± 3.1 mV, stable within a one-month period in a water stock solution, showing promising attributes for further valorization. Furthermore, the study delves into the antimicrobial activity of trimethylchitosan nanoparticles on Pseudomonas aeruginosa and confirms the benefits of both nanoformulation and modification of chitosan, as our prepared nanoparticles inhibit 50% of the bacterial population at concentration ≥160 mg L-1 within tested strains. Additionally, we identified a concentration of 5 mg L-1 that no longer impedes bacterial growth, allowing reliable verification of the effect of the prepared nanoparticles on Pseudomonas aeruginosa virulence factors, including motility, protease activity, hemolytic activity, rhamnolipids, pyocyanin, and biofilm production. Although trimethylchitosan nanoparticles exhibit promise as an effective antibiofilm agent (reducing biofilm development by 50% at concentrations ranging from 80 to 160 mg L-1) their impact on virulence manifestation is likely not directly associated with quorum sensing. Instead, it can probably be attributed to non-specific interactions with the bacterial surface. This exploration provides valuable insights into the potential of quaternized chitosan nanoparticles in addressing Pseudomonas aeruginosa infections and underscores the multifaceted nature of their antimicrobial effects.

Preparation strategies of mussel-inspired chitosan-based biomaterials for hemostasis.

Chitosan (CS) has been extensively studied in wound care for its intrinsic hemostatic and antibacterial properties. However, CS has limiting hemostasis applications on account of its drawbacks such as poor adhesion in humid environments and water solubility at neutral pH. CS-based biomaterials, inspired by mussel-adhesive proteins, serve as a suggested platform by biomedical science. The reports show that the mussel-inspired CS-based hemostatic structure has negligible toxicity and excellent adhesiveness. Biomedicine has witnessed significant progress in the development of these hemostatic materials. This review summarizes the methods for the modification of CS by mussel-inspired chemistry. Moreover, the general method for preparation of mussel-inspired CS-based biomaterials is briefly discussed in this review. This work is expected to give a better understanding of opportunities and challenges of the mussel-inspired strategy for the functionalization of CS-based biomaterials in hemostasis and wound healing. This review is hoped to provide an important perspective on the preparation of mussel-inspired CS-based hemostatic materials.

Improving the technology for obtaining of low molecular weight chitosan under conditions of controlled enzymatic cleavage

Relevance. Annotation. Experimental data on improving the production technology of regulated enzymatic cleavage of chitosan to obtain its low-molecular derivatives are presented. Experimental studies were carried out in the conditions of the Department of Disease Diagnostics, Therapy, Obstetrics and Animal Reproduction of the Moscow State Academy of Veterinary Medicine and Biotechnology — MVA named after K.I. Skryabin and on the basis of the All-Russian Research and Technological Institute of the Biological Industry.Methods. Acid-soluble chitosan from king crab shell (MM 700 kDa, SDA 85%), chitosan succinate (MM 330 kDa, SZ 75.2%), low-molecular food chitosan (hydrochloride) (MM 50 kDa) were used as raw materials for obtaining new modifications of chitosan, gel chitosan (2% solution in 2% acetic acid) manufactured by Bioprogress LLC.Results. As a result of the experiment, the technological parameters of obtaining low-molecular chitosan by enzymatic hydrolysis were selected. The greatest decrease in the dynamic viscosity of chitosan was reliably observed in the pilot-industrial series II (by 29.3 times), and the pilot-industrial series I and III — by 6.9 and 10.6 times, respectively. As a result of enzymatic hydrolysis of chitosan in the pilot series II, it was possible to reduce the molecular weight from 700 to 24 kDa, and in series I and III — to 102 and 66 kDa. Based on the research results, a technological scheme for obtaining low-molecular-weight chitosan derivatives by enzymatic hydrolysis has been developed, tested and proposed for industrial use, technical conditions have been developed.

Synthesis of Carboxylated Chitosan Amide Using Some Cyclic Anhydride and Their Activities as Antifungal

Chitosan is a natural polymer that has antifungal activity. It is necessary to modify chitosan into its derivatives to increase its activity. One modification of chitosan that has the potential to be developed as an antifungal is carboxylated chitosan amide because this chitosan derivative contains a carboxylic group and is more hydrophilic. This research aims to synthesize chitosan amide carboxylate using several cyclic anhydride compounds and test its antifungal activity against Aspergillus flavus. The cyclic anhydrides used in this research are maleic anhydride and phthalic anhydride. In the initial stage of chitosan amide carboxylate synthesis, reaction optimization was carried out at varying temperatures of 25, 50, and 72oC for 7 hours. Compound characterization was carried out using FTIR and UV-Vis spectrophotometry. The disc diffusion method tested the chitosan amide carboxylate product for its antifungal activity against Aspergillus flavus. The optimal MCA (Maleoyl Chitosan Amide) product is (MCA_50), synthesized at a reaction temperature of 50oC. Under these optimal reaction conditions, PCA_50 (Pthaloyl Chitosan Amide) was successfully synthesized to produce a brownish-yellow solid with a yield of 46.1% (w/w) and a degree of substitution (DS) of 41.93%. The diameter of the inhibition zone against Aspergillus flavus for PCA_50 was 30 mm at the 12th hour of observation. The product (PCA_50) has better antifungal activity than chitosan and MCA_50.

PROSPECTS FOR MODIFYING THE STRUCTURE OF CHITIN AND CHITOSAN OF HIGHER FUNGI TO EXPAND THE POTENTIAL OF THEIR APPLIED USE

The review is devoted to summarizing scientific data in the field of the chemical structure and properties of chitin and chitosan obtained from fungal biomass, and to analyzing directions for their modification for use in medicine and the food industry as substances with antibacterial, antiviral, wound-healing and anticoagulant activity. The features of chitin biosynthesis by fungi of the Basidiomycota, Ascomycota, Deuteromycota departments and chitosan biosynthesis by fungi of the Zygomycota department are covered. It has been shown that higher fungi contain chitin in their cell walls in the form of a chitin-glucan complex, while lower fungi (zygomycetes) contain chitin in the form of chitosan-glucan. Effective components of substrates that influence the production of polysaccharides by fungi have been identified - carbohydrates in the form of glucose, sucrose and maltose, organic forms of nitrogen in the form of yeast extract and corn flour, mineral components in the form of dihydrogen phosphate and dipotassium monohydrogen phosphate. Particular attention is paid to methods for isolating chitin and modifying it to chitosan with a detailed description of the physicochemical and biological properties of polymers. The review also presents the main reactions and methods for obtaining carboxymethyl and sulfo derivatives of chitin and chitosan. The biological properties and application of these groups of substances are described. In the carboxymethylation of chitin and chitosan, the choice of appropriate reaction conditions and reagents makes it possible to obtain carboxymethyl chitin, N-, O-, N,O-carboxymethylchitosan, or N,N-dicarboxymethylchitosan. The properties and applications of carboxymethyl derivatives of chitin and chitosan strongly depend on their structure, degree of substitution, and arrangement of amino or hydroxyl groups. The main reagents in the preparation of carboxymethyl derivatives are sodium monochloroacetate, monochloroacetic and glyoxalic acids. Carboxymethyl derivatives of chitin and chitosan are used as drug delivery systems, antimicrobial agents, in tissue engineering, as components of cosmetics and food products. Modification of chitosan with sulfate groups makes it possible to obtain chitosan 2-N-, 6-O-, 2-N-6-O- and 3-O-sulphates. The main sulfonating agents are oleum, pyridine and chlorosulfonic acid. Sulfonic derivatives of chitin and chitosan can be used as a basis for obtaining hemocompatible materials (with antithrombotic and antibacterial activities).

Chitosan as a Control Tool for Insect Pest Management: A Review.

Chitosan, a polysaccharide derived from the deacetylation of chitin, is a versatile and eco-friendly biopolymer with several applications. Chitosan is recognized for its biodegradability, biocompatibility, and non-toxicity, beyond its antimicrobial, antioxidant, and antitumoral activities. Thanks to its properties, chitosan is used in many fields including medicine, pharmacy, cosmetics, textile, nutrition, and agriculture. This review focuses on chitosan's role as a tool in insect pest control, particularly for agriculture, foodstuff, and public health pests. Different formulations, including plain chitosan, chitosan coating, chitosan with nematodes, chitosan's modifications, and chitosan nanoparticles, are explored. Biological assays using these formulations highlighted the use of chitosan-essential oil nanoparticles as an effective tool for pest control, due to their enhanced mobility and essential oils' prolonged release over time. Chitosan's derivatives with alkyl, benzyl, and acyl groups showed good activity against insect pests due to improved solubility and enhanced activity compared to plain chitosan. Thus, the purpose of this review is to provide the reader with updated information concerning the use and potential applications of chitosan formulations as pest control tools.

Fabrication of Glycine-Chitosan/TiO2 film for metanil yellow removal from water

This study focused on the modification of chitosan with glycine and TiO2 to improve its performance for adsorption application. It is the first study to use a combination of chitosan, glycine, and TiO2 in the preparation of composite films. The obtained chitosan-glycine/TiO2 composite films were extensively characterized using various techniques, including FT-IR, SEM, XRD, DSC, and tensile tests to study the functional groups, morphology, structure, thermal stability, and mechanical properties of composite films, respectively. FT-IR analysis confirmed the successful formation of the chitosan-glycine/TiO2 film, where chemical interaction occurred between the carboxyl groups of glycine and NH2 of chitosan through a condensation process and physical interaction occurred between chitosan-glycine and TiO2. SEM images revealed that the surface of chitosan-glycine/TiO2 composite films exhibited a rougher texture compared to the unmodified chitosan, indicating structural changes due to the addition of glycine and TiO2. XRD analysis indicated alterations in the crystallinity properties of chitosan upon the incorporation of glycine and TiO2. The DSC results demonstrated that the presence of glycine and TiO2 influences the thermal stability of chitosan. The tensile test revealed the improvement of tensile strength in the chitosan-glycine/TiO2 film, related to the existence of glycine and TiO2. The adsorption process of metanil yellow by the chitosan-glycine/TiO2 film was in accordance with the Langmuir isotherm model. In conclusion, the modification of chitosan with glycine and TiO2 resulted in the development of a promising adsorbent material with improved thermal stability, enhanced tensile strength, and a higher adsorption capacity for metanil yellow. These findings contribute to the potential application of chitosan-glycine/TiO2 films in various adsorption processes.

A review study on green synthesis of chitosan derived schiff bases and their applications

Chitosan is a bio-degradable, bio-compatible, non-toxic, and renewable biopolymer. The reactive amino group of chitosan has gained importance because using these amino groups can help achieve the different types of structural modification in chitosan. Chemical modification of chitosan via imine functionalization results in the formation of a chitosan Schiff base. The present review covers the green synthesis of chitosan Schiff bases using non-conventional green methods such as microwave irradiation, green solvent, ultrasound irradiation, and one-pot synthesis. These methods are energy-efficient and greener versions of the conventional condensation methods. Scientists have paid significant attention to the chitosan Schiff base because of its unique properties and versatility. These molecules display various biological applications, including antioxidant, antimicrobial, anticancer, antibacterial, and anti-fungal. In addition to biological applications, chitosan Schiff base also has other applications like corrosion inhibition, catalysis, metal ion adsorption, and as a sensor. Available literature particularly shows the different methods for the synthesis of chitosan Schiff bases and their different applications. This review gives detailed insight regarding sustainable approaches to the synthesis of chitosan derived Schiff bases and their applications in various emerging fields.

Synthesis and adsorption performance of temperature-sensitive imprinted composite poly (vinylidene fluoride) resin membranes with chitosan modification for selective separation of ReO4−

Purpose This study aims to prepare an imprinted composite membrane with grafted temperature-sensitive blocks for the efficient adsorption and separation of rhenium(Re) from aqueous solutions. Design/methodology/approach PVDF resin membrane was used as the substrate, dopamine and chitosan (CS) were used to modify the membrane surface and temperature-sensitive block PDEA was grafted on the membrane surface. Then acrylic acid (AA) and N-methylol acrylamide (N-MAM) were used as the functional monomers, ethyleneglycol dimethacrylate (EGDMA) as the cross-linker and ascorbic acid-hydrogen peroxide (Vc-H2O2) as the initiator to obtain the temperature-sensitive ReO4− imprinted composite membranes. Findings The effect of the preparation process on the performance of CS–Re–TIICM was investigated in detail, and the optimal preparation conditions were as follows: the molar ratios of AA–NH4ReO4, N-MAM and EGDMA were 0.13, 0.60 and 1.00, respectively. The optimal temperature and time of the reaction were 40 °C and 24 h. The maximum adsorption capacity of CS–Re–TIICM prepared under optimal conditions was 0.1071 mmol/g, and the separation was 3.90 when MnO4− was used as the interfering ion. The quasi first-order kinetics model and Langmuir model were more suitable to describe the adsorption process. Practical implications With the increasing demand for Re, the recovery of Re from Re-containing secondary resources becomes important. This study demonstrated a new material that could be separated and recovered Re in a complex environment, which could effectively alleviate the conflict between the supply and demand of Re. Originality/value This contribution provided a new material for the selective separation and purification of ReO4−, and the adsorption capacity and separation of CS–Re–TIICM were increased with 1.673 times and 1.219 time compared with other Re adsorbents, respectively. In addition, when it was used for the purification of NH4ReO4 crude, the purity was increased from 91.950% to 99.999%.

Oral delivery of a chitosan adjuvanted COVID-19 vaccine provides long-lasting and broad-spectrum protection against SARS-CoV-2 variants of concern in golden hamsters

Coronavirus disease 2019 (COVID-19) seriously threatens public health safety and the global economy, which warrant effective prophylactic and therapeutic approaches. Currently, vaccination and establishment of immunity have significantly reduced the severity and mortality of COVID-19. However, in regard to COVID-19 vaccines, the broad-spectrum protective efficacy against SARS-CoV-2 variants and the blocking of virus transmission need to be further improved. In this study, an optimum oral COVID-19 vaccine candidate, rVSVΔG-Sdelta, was selected from a panel of vesicular stomatitis virus (VSV)-based constructs bearing spike proteins from different SARS-CoV-2 strains. After chitosan modification, rVSVΔG-Sdelta induced both local and peripheral antibody response, particularly, broad-spectrum and long-lasting neutralizing antibodies against SARS-CoV-2 persist for 1 year. Cross-protection against SARS-CoV-2 WT, Beta, Delta, BA.1, and BA.2 strains was achieved in golden hamsters, which presented as significantly reduced viral replication in the respiratory tract and alleviated pulmonary pathology post SARS-CoV-2 challenge. Overall, this study provides a convenient, oral-delivered, and effective oral mucosal vaccine against COVID-19, which would supplement pools and facilitate the distribution of COVID-19 vaccines.

Active packaging incorporating chitosan, casein phosphopeptide, and plasmonic modification to maintain quality and regulate the respiration rate of fresh-cut Pyrus serotina Rehder during storage

In this study, chitosan (CS), casein phosphopeptide (CPP), and plasm modification were used to develop an active packaging that can extend the shelf-life of fresh-cut pear (FCP) (Pyrus serotina Rehder) at 4 °C. Results show that CS, CPP, and plasmonic modification increase water vapour permeability (WVP), improved the antibacterial (8%) and antioxidant properties (58–69%) of low-density polyethylene (LDPE) without adverse effects on mechanical strength. The application of CS/CPP active packaging resulted in significant improvements in various quality parameters of the packaged product. Browning was reduced by 48.80%, while weight loss decreased by 14.56%. The active packaging also exhibited potent inhibitory effects on microbial growth and respiration, with reductions of 47.74%. Additionally, the packaging demonstrated the ability to reduce the activity of crucial enzymes such as phospholipase D (PLD) by 35.71%, lipoxygenase (LOX) by 40.74%, polyphenol oxidase (PPO) by 35.71%, and malondialdehyde (MDA) by 34.79%. These combined effects extended the shelf-life of the FCP from 6 to 12 days. A comprehensive analysis of film properties, including moisture migration and respiration characteristics, indicated that the CS/CPP active packaging primarily contributed to mass loss reduction by inhibiting respiration rather than transpiration. This result proves that combining cold plasma, antioxidants, and antibacterial agents with modified LDPE can create a preservation package with composite functions.

Magnetic induction heating and drug release properties of magnetic carbon nanotubes

Aim The use of magnetic carbon nanotubes for multi-modal cancer treatment, incorporating both hyperthermia and drug delivery functions, has drawn substantial interest. Yet, the present method of regulating hyperthermia temperature involves manually adjusting the magnetic field intensity, adding to the complexity and difficulty of clinical applications. This study seeks to design novel magnetic carbon nanotubes capable of self-temperature regulation, and investigate their drug loading and release characteristics. Methods Using the co-precipitation method, we synthesized magnetic carbon nanotubes with a Curie temperature of 43 °C. A comprehensive investigation was conducted to analyze their morphology, crystal structure, and magnetic characteristics. To enhance their functionality, chitosan and sodium alginate modifications were introduced, enabling the loading of the antitumor drug doxorubicin hydrochloride (DOX) into these magnetic carbon nanotubes. Subsequently, the loading and release properties of DOX were investigated within the modified magnetic nanotubes. Results Under alternating magnetic field, magnetic carbon nanotubes exhibit self-regulating properties by undergoing a magnetic phase transition, maintaining temperatures around 43 °C as required for hyperthermia. On the other hand, during magnetic induction heating, the release percentage of DOX reached 23.5% within 2 h and 71.7% within 70 h at tumor pH conditions, indicating their potential for sustained drug release. Conclusions The prepared magnetic carbon nanotubes can effectively regulate the temperature during hyperthermia treatment while ensuring controlled drug release, which presents a promising method for preparing nanomaterials that synergistically enhance magnetic hyperthermia and chemotherapy drugs.

All-natural chitosan-based polyimine vitrimer with multiple advantages: A novel strategy to solve nondegradable plastic waste pollution

The increasing amount of nondegradable petroleum-based plastic waste releases chemical hazards, posing a significant threat to the environment and human health. Chitosan, derived from marine wastes, is an attractive feedstock for the preparation of plastic replacement due to its renewable and degradable nature. However, in most cases, complex chemical modifications of chitosan or hybridization with chemicals from fossil resources are required. Herein, we present a high-performance chitosan-based polyimine vitrimer (CS-PI) through a mild and catalyst-free Schiff base reaction between chitosan and vanillin. The CS-PI were formed by integrating dynamic imine bonds into the polymer networks, resulting in superior thermo-processability and mechanical performances. The tensile strength and Young’s modulus of the CS-PI films reached 38.72 MPa and 3.20 GPa, respectively, which was significantly higher than that of both commercial petroleum-based plastics and bioplastics. Additionally, the CS-PI films exhibited good light transmittance, self-healing ability, reprocess capacity, water resistance, and durability to various organic solvents. Moreover, the CS-PI films could be completely degraded under both acidic and natural conditions, enabling a sustainable circulation. Therefore, this work offers a new design strategy for developing all-natural environmentally friendly polymers as sustainable replacements for petroleum-based plastics, thus reducing the accumulation of nondegradable plastic waste.

Strategies for the Preparation of Chitosan Derivatives for Antimicrobial, Drug Delivery, and Agricultural Applications: A Review.

Chitosan has received much attention for its role in designing and developing novel derivatives as well as its applications across a broad spectrum of biological and physiological activities, owing to its desirable characteristics such as being biodegradable, being a biopolymer, and its overall eco-friendliness. The main objective of this review is to explore the recent chemical modifications of chitosan that have been achieved through various synthetic methods. These chitosan derivatives are categorized based on their synthetic pathways or the presence of common functional groups, which include alkylated, acylated, Schiff base, quaternary ammonia, guanidine, and heterocyclic rings. We have also described the recent applications of chitosan and its derivatives, along with nanomaterials, their mechanisms, and prospective challenges, especially in areas such as antimicrobial activities, targeted drug delivery for various diseases, and plant agricultural domains. The accumulation of these recent findings has the potential to offer insight not only into innovative approaches for the preparation of chitosan derivatives but also into their diverse applications. These insights may spark novel ideas for drug development or drug carriers, particularly in the antimicrobial, medicinal, and plant agricultural fields.

Chitosan-modified cotton fiber: An efficient and reusable adsorbent in removal of harmful cyanobacteria, Microcystis aeruginosa from aqueous phases

In the present study, to remove harmful cyanobacterial species Microcystis aeruginosa from aqueous phases, adsorption-based strategy was utilized. For this strategy, the surface of cotton fiber was modified using chitosan molecules to develop a highly efficient and ecofriendly adsorbent in removal of Microcystis aeruginosa from aqueous solution. The pristine cotton fiber could not remove M. aeruginosa, while the chitosan-modified cotton (CS-m-Cotton) showed the 95% of cell removal efficiency within 12 h. The surface characteristics of chitosan-modified cotton compared to the pristine cotton fiber was examined by various surface analysis methods. In addition, the pre-treatment of pristine cotton using sodium hydroxide solution was an important factor for enhancement of chitosan modification efficiency on the cotton fiber. The developed chitosan-modified cotton fiber could be reusable for M. aeruginosa cell removal after the simple desorption treatment using ultrasonication in alkaline solution. During the repeated adsorbent regeneration and reuse, the chitosan-modified cotton maintained its M. aeruginosa removal efficiencies (>90%). From the acute toxicity assessment using the chitosan-modified cotton and, the measurements of chemical oxygen demand and microcystin level changes in the M. aeruginosa treatment process using the adsorbent, the environmental safety of the adsorption strategy using the developed adsorbent could be confirmed. Based on our results, the chitosan-modified cotton fiber could be proposed as an efficient and ecofriendly solution for remediation of harmful cyanobacterial species occurring water resources.