Study on TEMPO-Mediated Oxidation of N-Succinyl Chitosan and the Water Retention Property

Enhanced physicochemical, rheological and antioxidant properties of highly succinylated succinoglycan exopolysaccharides obtained through succinic anhydride esterification reaction

Highly succinylated succinoglycan (HS-SG) was prepared by reacting succinic anhydride with succinoglycan (SG) exopolysaccharide isolated from Sinorhizobium meliloti. The rheological, physicochemical properties, and antioxidant effects of HS-SG were evaluated in comparison with SG. NMR and FTIR analyses confirmed that HS-SG retained the characteristic glycosidic structure of SG while showing a relative increase in succinyl functional groups. DSC analysis revealed that HS-SG 50, with a reaction molar ratio of SG to succinic anhydride of 1:50, exhibited a higher endothermic peak at 151 °C, indicating improved thermal stability compared to SG's peak at 93 °C. Rheological analysis demonstrated that HS-SG 50 had a viscosity 250 % higher than SG at a shear rate of 10 s-1. Unlike SG, whose viscosity dropped to less than 1 % above 60 °C, HS-SG 50 maintained about 30 % viscosity at the same temperature. Additionally, HS-SG 50 showed significantly enhanced antioxidant activity in DPPH and hydroxyl radical scavenging tests and was non-toxic in a cytotoxicity test using HEK-293 cells. These findings suggest that highly succinylated succinoglycan exhibits improved thermal stability, viscosity, and antioxidant properties, making it a promising biomaterial for applications in cosmetics, pharmaceuticals, biomedicine, and polysaccharide-based biotechnology.

Adsorption of Bisphenol A from Water Using Chitosan-Based Gels

The comonomer bisphenol A (BPA) finds applications in the plastics industry, where it is used in the production of polycarbonates, plastics, PVC, thermal paper, epoxy and vinyl ester resins, and polyurethane. The water, with which many of these materials come into contact, is one of the main sources of human exposure to BPA. When ingested or touched, BPA can damage organs, disrupt the endocrine and immune systems, generate inflammatory responses, and be involved in genotoxic processes. Therefore, the need to develop effective techniques for removing BPA from aqueous environments is imperative. This paper provides a comprehensive review regarding the effective removal of BPA from water, focusing on the performance and adsorption mechanisms of various adsorbents based on chitosan and chitosan composites. The chemical and physical factors, adsorption kinetics and models governing the adsorption process of BPA in chitosan materials are also examined. This review outlines that, despite considerable progress in the absorption of bisphenol using chitosan gels, further research is necessary to assess the efficacy of these adsorbents in treating real wastewater and in large-scale manufacture.

Synergistic antibacterial and wound healing effects of chitosan nanofibers with ZnO nanoparticles and dual antibiotics

One concern that has been considered potentially fatal is bacterial infection. In addition to the development of biocompatible antibacterial dressings, the screening and combination of new antibiotics effective against antibiotic resistance are crucial. In this study, designing hemostasis electrospun composite nanofibers containing chitosan (CS), polyvinyl pyrrolidone (PVP) and Gelatin (G) as the major components of hydrogel and natural nanofibrillated sodium alginate (SA)/polyvinyl alcohol (PVA) and ZnO nanoparticles (ZnONPs) combination as the nanofiller ingredient, has been investigated which demonstrated significant potential for accelerating wound healing. The hydrogels were developed for the delivery of the amikacin and cefepime antibiotics, along with zinc oxide nanoparticles that were applied to an electrospun layer. Amikacin is a highly effective aminoglycoside antibiotic, particularly for hospital-acquired infections, but its use is limited due to its toxicity. By utilizing it in low concentrations in the form of nanofibers and combining it with cefepime, which exhibits synergistic effects, enhanced efficacy against bacterial pathogens is achieved while potentially minimizing cytotoxicity compared to individual antibiotics. This dressing demonstrated efficient drug release, flexibility, and good swelling properties, indicating its suitable mechanical properties for therapeutic applications. After applying the biocompatible hydrogel to wounds, a significant acceleration in wound closure was observed within 14 days compared to the control group. Furthermore, the notable antibiotic and anti-inflammatory properties underscore its effectiveness in wound healing, making it a promising candidate for medical applications.

Films based on TEMPO-oxidized chitosan nanoparticles: Obtaining and potential application as wound dressings

A series of novel films based on TEMPO-oxidized chitosan nanoparticles were prepared by casting method. Fourier transform infrared spectroscopy (FTIR) was employed to ascertain the chemical structure of TEMPO-oxidized chitosan. The surface morphology of the TEMPO-oxidized chitosan nanoparticles was analyzed by atomic force microscopy (AFM). The physicochemical (area density, thickness, iodine sorption, roughness), functional (moisture sorption, liquid absorption capacity, weight loss upon contact with the liquid, and water vapor transmission rate), antibacterial, and antioxidant properties of films based on TEMPO-oxidized chitosan nanoparticles were also investigated. The physicochemical properties of the films varied widely: area density ranged from 77.83 ± 0.06 to184.46 ± 0.05 mg/cm2, thickness varied between 80.5 ± 1.6 and 200.5 ± 1.6 μm, iodine sorption spanned from 333.7 ± 2.1 to166.4 ± 2.2 mg I2/g, and roughness ranged from 4.1 ± 0.2 to 5.6 ± 0.3 nm. Similarly, the functional properties also varied significantly: moisture sorption ranged from 4.76 ± 0.03 to 9.62 ± 0.11 %, liquid absorption capacity was between 129.04 ± 0.24 and 159.33 ± 0.73 % after 24 h, weight loss upon contact with the liquid varied between 31.06 ± 0.35 and 45.88 ± 0.58 % after 24 h and water vapor transmission rate ranged from 1220.10 ± 2.91to1407.77 ± 5.22 g/m2 day. Despite the wide variations in physicochemical and functional properties, all films showed maximum bacterial reduction of Staphylococcus aureus and Escherichia coli, although they exhibited low antioxidant activity. The results suggest that the films could be effectively utilized as antibacterial wound dressings.

Drug Polymeric Carrier of Aceclofenac Based on Amphiphilic Chitosan Micelles

Amphiphilic micelles based on chitosan (CS) were applied as drug carriers of aceclofenac (ACF) as a potential method to induce its bioavailability and therapeutic efficiency. N-octyl-N,O-succinyl CS (OSCS), an amphiphilic CS derivative, was successfully synthesized and loaded physically by ACF at different pH values and using different dosages of ACF, forming ACF-loaded polymeric micelles (PMs). The obtained PMs and ACF-loaded PMs were characterized by different analytical techniques, including AFM, TEM, DLS, UV-vis spectrophotometry, 1H NMR spectroscopy, and FT-IR spectroscopy. The pH 5 sample with a 30% ACF/polymer ratio showed the highest ACF loading capacity (LC) and entrapment efficiency (EE). In vitro release behaviors of pure ACF and ACF-loaded PMs at each release point indicated that the release profile of pH-responsive PMs loaded with ACF demonstrated quicker release rates (94% after 480 min) compared to the release behavior noticed for free ACF (59.56% after 480 min). Furthermore, the release rates exhibit a notable rise when the pH is increased from 1.2 to 4.7. In the carrageenan-induced inflammation model of paw edema in rats, it has been demonstrated that the injection of ACF-loaded PMs (at a dose of 10 mg/kg) resulted in a strengthened inflammatory activity compared to the injection of free ACF at equivalent dosages as well as at time intervals. However, the use of ACF-loaded PMs for a duration of 6 h displayed a notable reduction of paw edema, with an inhibition percentage of 85.09%, in contrast to the 74.9% inhibition percentage observed for the free ACF medication.

Chitosan Based Materials in Cosmetic Applications: A Review

This review provides a report on the properties and recent advances in the application of chitosan and chitosan-based materials in cosmetics. Chitosan is a polysaccharide that can be obtained from chitin via the deacetylation process. Chitin most commonly is extracted from cell walls in fungi and the exoskeletons of arthropods, such as crustaceans and insects. Chitosan has attracted significant academic interest, as well as the attention of the cosmetic industry, due to its interesting properties, which include being a natural humectant and moisturizer for the skin and a rheology modifier. This review paper covers the structure of chitosan, the sources of chitosan used in the cosmetic industry, and the role played by this polysaccharide in cosmetics. Future aspects regarding applications of chitosan-based materials in cosmetics are also mentioned.

Preparation of a novel glucose oxidase-N-succinyl chitosan nanospheres and its antifungal mechanism of action against Colletotrichum gloeosporioides

In this work, a new glucose oxidase-N-succinyl chitosan (GOD-NSCS) nanospheres was prepared through the immobilization of glucose oxidase (GOD) on N-succinyl chitosan (NSCS) nanospheres. Compared to the free GOD, GOD-NSCS nanospheres demonstrated the excellent anti-Colletotrichum gloeosporioides activity with the EC₅₀ values of 211.2 and 10.7 μg/mL against mycelial growth and spores germination. The computational biology analysis demonstrated that the substrate presented the similar binding free energy with GOD-NSCS nanospheres (-27.64 kcal/mol) compared with the free GOD (-24.04 kcal/mol), indicating that GOD-NSCS nanospheres had the same oxidation efficiency and produced more H₂O₂. Moreover, the enzyme activity stability of GOD-NSCS nanospheres could be prolonged to 10 d. The cell membrane was destructed by the treatment of H₂O₂ produced by GOD, leading to the cell death. In vivo test, GOD-NSCS nanospheres treatment significantly prolonged the preservation period of mangoes 2-fold. Collectively, these results suggested that GOD-NSCS nanospheres suppresses anthracnose in postharvest mangoes by inhibiting the growth of C. gloeosporioides and might become a potential natural preservative for fruits and vegetables.

A smart cauliflower-like carrier for astaxanthin delivery to relieve colon inflammation

As a fat-soluble carotenoid, astaxanthin has excellent antioxidant and anti-inflammation biological activities, but its poor biocompatibility and low stability limit application of astaxanthin in the food industry. In this study, cauliflower-like carriers (CCs) were constructed based on caseinate, chitosan-triphenylphosphonium (TPP) and sodium alginate through an electrostatic self-assembly method to improve the biocompatibility, stability and targeting transport properties of astaxanthin. The smart CCs showed pH-response release and mitochondrial targeted characteristics. In vitro studies demonstrated that the CCs could improve the internalization of astaxanthin, and significantly inhibited the excessive production of reactive oxygen species and the depolarization of mitochondrial membrane potential caused by oxidative stress. In vivo studies revealed that the astaxanthin-loaded CCs could effectively relieve the colitis induced by dextran sodium sulfate and protect the integrity of the colon tissue structure. The astaxanthin-loaded CCs could significantly inhibit the expression of inflammation factors such as interleukin-1β, interleukin-6, tumor necrosis factor alpha, cyclooxygenase-2, myeloperoxidase, inducible nitric oxide synthase, and nitric oxide. Moreover, the astaxanthin-loaded CCs could maintain the expression of zonula occludens-1, increase the abundance of Firmicutes and Lactobacillaceae in the intestine. In a word, the constructed astaxanthin delivery system provided a potential application for the oral uptake hydrophobic bio-activator in intervention of ulcerative colitis.

Preparation and characterization of succinyl chitosan and succinyl chitosan nanoparticle film: In vitro and in vivo evaluation of wound healing activity

Development of novel wound dressing materials having the ability to prevent bacterial infections and capable of accelerating the tissue regeneration process is utmost important, since the wounds in patients can cause severe health issues. In the present work, we synthesized novel N-succinyl chitosan nanoparticles (N-SuC NPs) films and tested their antimicrobial, cytotoxicity, and in vitro and in vivo wound healing activity. N-SuC NPs were synthesized by ionic gelation method, and subsequently N-SuC NPs films were prepared by solution casting method using synthesized N-SuC NPs. The prepared N-SuC NPs films showed significant antimicrobial activity against Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration of 6 mg/mL and <8 mg/mL, respectively. The biocompatibility and the in vitro wound healing activity of N-SuC NPs films were analyzed using human dermal fibroblast (HDF) cells. In vivo cutaneous wound healing of the N-SuC NPs film was investigated using the Wister rat model, and the studies showed that the N-SuC NPs film significantly accelerated the wound healing process by inducing more blood vessels formation and tissue granulation. The experimental results showed that synthesized N-SuC NPs film had excellent antimicrobial, cytotoxicity and wound healing activity, indicating that it could be used in biomedical applications.

Aqueous Modification of Chitosan with Itaconic Acid to Produce Strong Oxygen Barrier Film

In this study, the chemical modification of chitosan using itaconic acid as a natural-based unsaturated dicarboxylic acid was investigated. In an aqueous environment, the amine group of chitosan reacts with itaconic acid to produce a chitosan derivative with pyrrolidone-4-carboxylic acid group. On the basis of the elemental analysis, 15% of the amine groups of chitosan reacted, thus creating modified chitosan with amine and carboxylic acid functionalities. Due to the presence of amine and carboxylic acid groups, the surface charge properties of the chitosan were notably altered after itaconic acid modification. In an aqueous solution, the modified chitosan exhibited zwitterionic properties, being cationic at low pH and turning anionic when the pH was increased over 6.5, whereas the original chitosan remained cationic until pH 9. Furthermore, it was demostrated that the modified chitosan was suitable for the preparation of a self-standing film with similarly high transparency but notably higher mechanical strength and oxygen barrier properties compared to a film made from the original chitosan. In addition, the thermal stability of the modified chitosan film was higher than that of the original chitosan film, and the modified chitosan exhibited flame-retardant properties.