查找使用阿拉丁产品的科研文献

pH Sensitive phosphorylated chitosan hydrogel as vaccine delivery system for intramuscular immunization

Jianye Wei,Wei Xue,Xifei Yu,Xiaozhong Qiu,Zonghua Liu

In the field of immunotherapy, immune vaccinations have received more and more attention for disease prevention and treatment. In immune vaccination, efficient vaccine adjuvants are necessary due to the weak immunogenicity of vaccines. Some traditional vaccine adjuvants have been widely used but have shown obvious limitations such as poor biosafety. Therefore, researchers make a great effort to develop more functional novel immune adjuvants such as chitosan-based immune adjuvants. However, chitosan is poorly water soluble, which greatly limits its application as immune adjuvants, regardless of its good biocompatibility, biodegradability, and other biological activities. In this work, we prepared a water-soluble chitosan derivative phosphorylated chitosan (PCS) and evaluated its potential as a novel immune adjuvant. PCS was found to be pH sensitive: specifically, it was water soluble at pH < 7.0 but began to gel at pH >7.0. By virtue of this, neutral PCS aqueous solutions containing ovalbumin (OVA) antigen was intramuscularly injected into test mice, which would transform to an OVA-containing gel network for OVA immunization. The results showed that the use of 30 mg/mL PCS-based hydrogel as vaccine delivery system contributed to significantly higher level of antigen-specific immune responses, including higher level of antigen-specific IgG antibodies, IFN-γ and IL-4 cytokines secretion by splenocytes, as well as memory CD4+ and CD8+ T cells. In vivo imaging and immunohistochemistry assays suggest that the improved immunization efficacy may be attributed to the controlled release of antigen from injection site by PCS gel network, and then prolonged antigen stimuli to the immune system. From the results, PCS could be developed as a promising vaccine delivery system for immunotherapy.

An investigation of chitosan and its derivatives on red blood cell agglutination

Xuan Zhou,Xinshuo Zhang,Jianjun Zhou,Lin Li

6-Deoxy-6-(2-aminoethyl) amino chitosan (CS-AEA) and aminoethyl modified CS-AEA (CS-AEA-AEM) were synthesized and characterized using FTIR, NMR and elemental analysis. The results showed that the expected CS derivatives were obtained, and the amine group content increased successively in CS, CS-AEA and CS-AEA-AEM. The red blood cell (RBC) agglutination behaviors in solutions of CS and its derivatives were studied using optical microscopy (OM) and ultraviolet-visible (UV-Vis) spectrophotometry. The results demonstrated that the agglutination of RBCs became more evident upon decreasing the pH value and increasing the concentration. Although CS-AEA-AEM had the highest content of amine groups, CS-AEA exhibited the best agglutination performance under the pH and concentration range studied. Potentiometric titration and ionization degree calculations showed that the agglutination behavior of RBCs was determined by the number of protonated amines in CS or its derivatives. Hemocompatibility tests showed that the hemolysis of CS derivatives increased after modification, and the CS derivatives could be classified as a slightly hemolytic material. We have sucessfully developed a CS derivative (CS-AEA) with very good RBC agglutination performance under neutral conditions.

Supramolecular hydrogel of poly(vinyl alcohol)/chitosan: A dual cross-link design

Zheng Zhang,Tingting Li,Yuan Liu,Fang Shang,Bing Chen,Yunxia Hu,Sui Wang,Zhiyong Guo

Supramolecular hydrogels are increasingly fascinating soft polymeric materials formed by noncovalent interactions. Poly(vinyl alcohol) (PVA), chitosan and graphite oxide (GO), good biocompatibility, and nontoxicity, are green materials with potential applications in biomaterials. Herein, a dual cross-link supramolecular hydrogel of PVA/chitosan in the presence of GO was prepared. Without addition of any organic cross-linker, the dual-network PVA/chitosan hydrogel was obtained, namely GO nanosheets as 2D cross-linker and H-bonding between PVA chains. For one thing, GO nanosheets induce the physical network formation through electrostatic interaction between positively charged PVA, chitosan, and negatively charged GO. For another, PVA chains can be connected by H-bonding through freezing/thawing measurements, resulting in the formation of another physical network. To investigate the performance of the PVA/chitosan/GO hydrogel, infrared spectrum, swelling test, thermal analysis, rheological study, and self-healing tests were conducted. The result showed that PVA/chitosan hydrogel in the presence of GO is not only self-healable, but also pH-responsive and temperature-dependent.

O-Carboxymethyl Chitosan Supported Heterogeneous Palladium and Ni Catalysts for Heck Reaction

Dongjun Lv,Mingjie Zhang

Two polymer catalysts (Pd-OCMCS and Ni-OCMCS) with good reusability were synthesized by coordinating Pd and Ni ontoO-carboxymethyl chitosan (OCMCS). The chemical structure and thermal stability of prepared catalysts were determined by Fourier transform infrared (FT-IR) spectra, Energy Dispersive Spectrometer (EDS)analysis, X-ray diffraction (XRD), and thermogravimetric analyzer (TG-DTG), and the analysis results showed that the Pd and Ni ions coordinated onto the OCMCS and formed a ligand with the –COOH group, amino groups, and –OH group on the OCMCS, and the EDS and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) analysis results showed that the loading amounts of Pd and Ni were approximately 8.3% and 8.9%, respectively. In the Heck reaction between aryl halides andn-butyl acrylate catalyzed by the prepared catalyst, the test results showed that the product yield followed the order of aryl iodide > aryl bromide > aryl chloride. Additionally, the product yield for the aryl iodide and aryl bromide could reach up to 99% and 96%, respectively. Moreover, the electron-withdrawing and electron-donating property of the group on the aryl also affected the product yield, and the product yield for aryl halides with electron-withdrawing groupp-NO2,p-CH3CO, andp-CHO was higher than that with electron-donating groupp-CH3.Keywords:O-carboxymethyl chitosan;biopolymer-supported catalyst;Pd-OCMCS;Ni-OCMCS;heck reaction

Chitosan-based magnetic/fluorescent nanocomposites for cell labelling and controlled drug release

Yongling Ding,Hong Yin,Shirley Shen,Kangning Sun,Futian Liu

A chitosan-based drug delivery system, composed of Fe3O4 magnetic nanoparticles (MNPs), CdTe@ZnS quantum dots (QDs) and the anti-cancer drug doxorubicin (DOX), was designed and fabricated. The surfaces of MNPs were modified with carboxymethyl chitosan (CMCS) to minimise the possible fluorescence quenching triggered by magnetic cores. Glutaraldehyde was used as a crosslinking agent to create chemical covalent conjunction between different components, thus enhancing the stability of the obtained nanocomposites. The resulting nanocomposites retain favourable magnetic and fluorescence properties and can be used for bimodal cellular imaging. A sustained pH dependent DOX release with more release at pH = 5.3 was observed. The nanocomposites exhibited low cytotoxicity and CLSM images confirmed the cell fluorescence labelling properties and time-dependent cellular uptake. In summary, the chitosan-based nanocomposites developed in this work provided highly integrated functionalities and are promising for controlled drug delivery and also suitable for in situ cellular imaging.

Adsorption of RE3+ from aqueous solutions by bayberry tannin immobilized on chitosan

Xianying Qiu,Yueyue Shen,Ruilin Yang,Hongcheng Zhang,Shilin Zhao

Carboxymethyl chitosan-methacrylic acid gelatin hydrogel for wound healing and vascular regeneration

Jingrong Yu,Zhengkun Gao,Qingyue Han,Zi Wang,Wenjie Zhang,Jie Zhao,Shan Qiao,Xinxin Zou,Fengjie Huang

At present, wound dressings in clinical applications are primarily used for superficial skin wounds.However these dressings have significant limitations, including poor biocompatibility and limited ability to promote wound healing. To address this issue, t this study used aldehyde polyethylene glycol as the cross-linking agent to design a carboxymethyl chitosan-methacrylic acid gelatin hydrogel with enhanced biocompatibility, which can promote wound healing and angiogenesis.The CSDG hydrogel exhibites acid sensitivity, with a swelling ratio of up to 300%. Additionally, it exhibited excellent resistance to external stress, withstanding pressures of up to 160 kPa and self-deformation of 80%. Compared to commercially available chitosan wound gels, the CSDG hydrogel demonstrates excellent biocompatibility, antibacterial properties, and hemostatic ability. Both in vitro and in vivo results showed that the CSDG hydrogel accelerated blood vessel regeneration by upregulating the expression of CD31, IL-6, FGF, and VEGF, thereby promoting rapid healing of wounds. In conclusion, this study successfully prepared the CSDG hydrogel wound dressings, providing a new approach and method for the development of hydrogel dressings based on natural macromolecules.

Chitosan hydrogel membrane embedded by metal-modified biochars for slow-release fertilizers

Mengqiao Wu,Jiawei Lu,Yan Zhang,Zhixin Ling,Ruohui Lu,Jie Zhu,Yongfu Li,Yanjiang Cai,Hai Xiang,Zuyong Zhang,Bing Yu

Slow-release fertilizers show great promise for advancing agricultural sustainability by enhancing nutrient efficiency and mitigating environmental impacts. Herein, we propose an approach that embeds chitosan hydrogel membranes with metal-modified biochars to encapsulate N-P-K compound fertilizers, referred to as CS-MBC-SRFs. Our results demonstrate that CS-MBC-SRFs exhibit superior slow-release performance for N, P, and K compared to others (commercial NPK compound fertilizers, chitosan-coated, and biochar-embedded chitosan-coated fertilizers). Over a 33-day soil column test, CS-MBC-SRFs showed cumulative leaching ratios of <8.93 % for N, 18.4 % for P, and 14.4 % for K. Incorporating metal-modified biochar into the chitosan hydrogel membrane significantly enhances its swelling and mechanical properties while maintaining biodegradability and water-retention capacity. Mechanistic investigations reveal that nutrient release from CS-MBC-SRFs primarily occurs via diffusion through the hydrogel membrane, with the metal-modified biochar surface enhancing nutrient adsorption and delaying release. Additionally, the metal-modified biochars improved swelling and mechanical properties of the chitosan hydrogel membrane, significantly reducing nutrient diffusion. Pot tests demonstrated that CS-MBC-SRFs effectively promoted chili plant growth, ensuring high N-P-K utilization and improving chili fruit nutritional indices. Economic analysis further highlights the promising application prospects of CS-MBC-SRFs.

Double-alternating injectable multifunctional hydrogel based on chitosan for skin wound repair

Yongyi Yang,Rong Liu,Li Xie,Yang Li,Mengqi Chen,Huang Zhu,Qingqing Pan

Injectable hydrogels can be suitable for any irregular wounds to play an important role in wound healing, which have attracted much attention from researchers. Here, a chitosan-based double alternating injectable hydrogel had been proposed, which aligned with characteristics of wound healing. First of all, carboxymethyl chitosan (CMCS) and oxidized gellant (OGG) were used to fabricate above double-alternating injectable hydrogel skeleton (COG) through Schiff base bond. Then, dipotassium glycyrrhizinate (DPG) and bioactive glass (BG) were loaded respectively into COG, forming COG2-D10 and COG2-B0.5 hydrogel. Various properties of above hydrogels such as rheological behaviors, injectable capability, cytocompatibility, antibacterial and anti-inflammatory activity were systematically investigated. The results indicated that above hydrogel not only had a stable network structure, good toughness, injectability, and excellent adhesive properties, but also exhibited efficient antibacterial, anti-inflammatory, hemostatic, and biocompatible properties. The investigation of in vivo full-thickness skin wound healing showed that compared with COG2-D10 or COG2-B0.5 hydrogel alone, the double-alternating COG2-D10/COG2-B0.5 hydrogel could better enhance the efficacy of drugs, promote cell migration and proliferation, accelerate collagen fiber deposition and neovascularization, and significantly improve wound healing ( p  < 0.01). Therefore, the double-alternating therapy strategy of hydrogel will provide a new approach for the clinical treatment of skin wound healing.

Dual structure on-demand release chitosan-based coating film for peach preservation

Hongyi Ren,Shengzi Li,Keying Ding,Yan Wang,Qiping Zhan,Yonghua Zheng,Zhengguo Wu,Peng Jin

After harvest, fruits and vegetables go through the stages of storage, transportation and sales, and how to regulate the role of preservative in different stages is an urgent problem to be solved. Herein, chitosan-stearic acid is synthesized, then interacting with trans-2-hexenal (E2H) to prepare nanoclusters. Subsequently, the temperature-sensitive liposomes were designed to encase E2H by using the special temperature-responsive open-chain phospholipids, and then combined with chitosan to obtain chitosan-based coating film for peach preservation. The thermosensitive liposomes were uniformly distributed, highly dispersed and spherical, which has excellent temperature response characteristics, and the release of active substances could be regulated in the temperature range of 10 °C-40 °C to achieve the effect of on-demand release. In addition, thermosensitive liposomes also have excellent antioxidant and antibacterial activities. Therefore, the obtained chitosan-based coating could maintain the freshness of peaches, improve the quality and extend the storage period of peaches. The edible chitosan coating and active preservative prepared in this study have potential application value in responsive intelligent active packaging.

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

Yumeng Gao,Jing Wu,Jian Shen,Yan Xu,Lu Li,Wentao Wang,Ninglin Zhou,Ming Zhang

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.

Chitosan-hydroxypropyl methylcellulose and sodium alginate bilayer edible films for chestnut preservation

Mengyu Liu,Peiying Zhang,Yanwen Wu,Jie Ouyang

To address the challenge of preserving fresh chestnuts, chitosan (CS), hydroxypropyl methylcellulose (HPMC), nisin (N), and sodium alginate (SA) were utilized in the preparation of a bilayer edible film named CS-HPMC-N/SA, which was compared to the monolayer films CS-HPMC and CS-HPMC-N. In comparison to the CS-HPMC film, the CS-HPMC-N and CS-HPMC-N/SA films exhibited increased water vapor permeability (WVP), oxygen permeability, and thickness, while transparency, tensile strength (TS), and elongation at break (EAB) were reduced. The bilayer film CS-HPMC-N/SA showed higher WVP, transparency, thickness, and EAB, but lower TS than the monolayer film CS-HPMC-N. The chestnuts coated with CS-HPMC-N/SA showed lower respiratory intensity and decay rate compared to those coated with CS-HPMC and CS-HPMC-N. These results suggested that the bilayer film CS-HPMC-N/SA, containing nisin, has potential as an edible material for preserving fresh chestnuts.