查找使用阿拉丁产品的科研文献

Using Electrodeposition of Carboxylated Chitosan for Green Preparation of Copper Nanoclusters and Nanocomposite Films

Zhang Xiaoli,Li Tingxue,Wang Qinghua,Yang Yan,Zhang Chenyu,Liu Yaning,Wang Yifeng

On the basis of coordinated electrodeposition of carboxylated chitosan (CCS), we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films. The method shows a range of benefits, such as the convenient and eco-friendly process, mild conditions, and simple post-treatment. The experimental results reveal that a homogeneous deposited film (Cu NCs/CCS nanocomposite film) is generated on the Cu plate (the anode) after electrodeposition, which exhibits an obvious red florescence. The results from TEM observation suggest there are nanoparticles (with the average particle size of 2.3 nm) in the deposited film. Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film. Moreover, the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS, which enables promising application in the electrochemical sensing. By means of fluorescence properties of Cu NCs, the Cu NCs/CCS film also owns the potential in fluorescence detection. Therefore, this work builds a novel method for the green synthesis of Cu NCs, meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.

Chitosan-Based Layer-by-Layer Assembly: Towards Application on Quality Maintenance of Lemon Fruits

Fangyuan Chen,Jinglin Zhang,Cunkun Chen,M. G. Gloire Martha Kowaleguet,Zhaojun Ban,Lifeng Fei,Chengchen Xu

We fabricated a novel chitosan-carboxymethyl cellulose (CMC) layer-by-layer assembly system to facilitate the postharvest quality of the fresh produce. Fourier transform infrared spectroscopy (FTIR), TA-XT2 texture analyzer, water vapor permeability (WVP) analyzer, and scanning electron microscopy (SEM) were applied to compare the properties of chitosan and layer-by-layer assembly. The strategy involved the optimization of water vapor permeability, puncture strength, and elasticity properties of multiplayer polymer coating. Results showed that the lemon ( Citrus limon (L.) Burm. f.), coated by chitosan-CMC layer-by-layer assembly, displayed significantly higher lemon firmness and vitamin C content with excellent morphology, as well as inhibited weight loss and flesh browning. This study could provide support for quality maintenance in the fruit and vegetable industry and make a significant contribution to the utilization of the natural polysaccharide as a viable resource.

A three-dimensional crosslinked chitosan sulfate network binder for high-performance Li–S batteries

Jianwen Feng,Huan Yi,Zhiwen Lei,Jun Wang,Hongbo Zeng,Yonghong Deng,Chaoyang Wang

Poor cycling performance caused by the shuttle effect of polysulfides is the main obstacle in the development of advanced lithium–sulfur (Li–S) batteries. Functional polymer binders with polar groups can effectively adsorb polysulfides chemically, thereby suppressing the shuttle effect. Herein, a robust three-dimensional crosslinked polymer network, which demonstrates excellent mechanical property and strong affinity for polysulfides , is prepared by the aldimine condensation and coordination reactions. The crosslinked chitosan sulfate network (CCSN) significantly enhances the cycling performance and rate capability of the sulfur cathode. The CCSN-based sulfur cathode exhibits a high initial discharge capacity of 824 mAh g −1 with only 0.082% average capacity loss per cycle at 1 C. At a high rate of 4 C, the cathode exhibits a high capacity retention of 84.8% after 300 cycles. Moreover, the CCSN-based sulfur cathode exhibits an excellent cycling performance at a high sulfur loading of 2.5 mg cm −2 , which indicates the excellent mechanical strength and binding performance of the CCSN binder for high-energy density Li–S batteries. This study demonstrates a viable approach for developing high-performance Li–S batteries for practical application.

Preparation of sulfonate chitosan microspheres and study on its adsorption properties for methylene blue

Hongxing Shi,Chengya Dong,Yuanyuan Yang,Yuanrui Han,Fei Wang,Chaoxian Wang,Jiying Men

Dyes bring a lot of benefits to our lives, however, as common organic pollutants , they have destructive influences on the environment. Firstly, glutaraldehyde crosslinked chitosan microspheres (GCS) are prepared via inverse-phase suspension polymerization . Then, GCS microspheres are acted as the base material, ammonium persulfate (Aps) as the initiator, sodium styrene sulfonate (SSS) as anionic functional monomer, functional microspheres (GCS-g-PSSS) are prepared by surface grafting polymerization. The amount of monomer and Aps, temperature and reaction time is respectively explored. The chemical structures and physicochemical properties of functional microspheres were characterized by FT-IR, zeta potential , scanning electron microscope and X-ray photoelectron spectroscopy. The adsorption kinetic at different temperature and initial concentration is studied and fitted. The adsorption isotherms of GCS-g-PSSS for MB are explored at different pH, temperature and salinity. The adsorption capacity of GCS-g-PSSS for MB is 820.1 mg/g at 318 K. The adsorption isotherms at different temperature are fitted by Langmuir, Freundlich, Dubinin-Radushkevich and Temkin. Thermodynamic parameters imply that adsorption is a spontaneous and endothermic process. And this adsorbent has good reusability. The adsorption ability of GCS-g-PSSS microspheres is also excellent for other cationic dyes. Thus, GCS-g-PSSS microspheres might serve as a promising adsorbent for contaminated water scavenging.

A Natural Eumelanin-Assisted Pullulan/Chitosan Hydrogel for the Management of Diabetic Oral Ulcers

Ying Li,Yajing Xiang,Yuxi Chen,Yingying Wang,Wei Dong,Yan Liu,Xiaoliang Qi,Jianliang Shen

Existing methods for treating diabetic oral ulcers often fall short in clinical environments due to potential bacterial contamination, oxidative harm, and hindered angiogenesis throughout the healing process. Here, a hydrogel patch (HYG2) have been developed for local in situ application. HYG2 comprises oxidized pullulan, quaternized chitosan, and eumelanin nanoparticles derived from cuttlefish ink. These components work together to efficiently heal wounds associated with diabetic oral ulcers. Application begins with a simple local injection that quickly forms a protective barrier over the mucosa, effectively stopping bleeding and counteracting inflammatory agents. HYG2 is distinguished by its strong antibacterial properties and capacity to eliminate reactive oxygen species, promoting bacteria clearance and managing oxidative stress, which accelerates the healing phase from inflammation to tissue regeneration. Additionally, HYG2's 3D structure, incorporating elements from natural sources, offers exemplary support for structural and nutritional cell needs. This enhancement fosters cell adhesion, migration, and proliferation, along with further angiogenesis during mucosal remodeling. Ultimately, HYG2 is fully absorbed by the body after serving its therapeutic functions. Evidence from in vitro and in vivo studies shows that HYG2 hydrogel markedly accelerates mucosal wound repair, making it a promising treatment for diabetic oral ulcers.

Synthesis, characterization of catechin-loaded folate-conjugated chitosan nanoparticles and their anti-proliferative effect

Buyun Liu,Yongli Wang,Qijian Yu,Dapeng Li,Feng Li

Synthesis of pH-responsive isolated soy protein/carboxymethyl chitosan microspheres for sustained pesticide release

Long Chen,Xinhua Zhou,Guanquan Lin,Huayao Chen,Li Hao,Hongjun Zhou

In order to improve the utilization rate of avermectin (AVM), a complex was prepared by electrostatic self-assembly using isolated soy protein (ISP) and carboxymethyl chitosan (CMCS) for loading AVM to obtain ISP/CMCS@AVM microspheres. The encapsulation efficiency (EE), sustained release property, ultraviolet (UV) protective ability, and toxicity of the microspheres were evaluated, and the release kinetics of AVM from the microsphere at different pHs were investigated. The results demonstrated that the average particle size of ISP/CMCS@AVM was 283.95 nm, and the EE reached 88.42% for AVM after denaturation. After 70 h of exposure to UV light, the residual rate of AVM in ISP/CMCS@AVM was 78.12%, which was significantly higher than 35.18% in the AVM emulsion. Moreover, the formulation imparted pH sensitivity and sustained-release property to AVM and was consistent with the Korsmeyer–Peppas model, controlled by Fick diffusion. Finally, the insecticidal toxicity of ISP/CMCS@AVM did not differ significantly from that of unmodified AVM. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48358.

Fabrication of chitosan based luminescent nanoprobe with aggregation-induced emission feature through ultrasonic treatment

Xin Hu,Shengxian Yu,Guang Yang,Wei Long,Teng Guo,Jianwen Tian,Meiying Liu,Xiancai Li,Xiaoyong Zhang,Yen Wei

Chitosan is an abundant natural polysaccharide that contains a lot of amino and hydroxyl groups. It possesses great potential for biomedical applications owing to its low toxicity, biodegradability and low cost. Herein, a novel chitosan-based fluorescent copolymer (WS-CS-TPA) was designed and synthesized via nucleophilic substitution of hexachlorocyclotriphosphazene (HCCP), water-soluble chitosan (WS-CS) and an aggregation-induced emission (AIE) fluorogen (AIEgen) triphenylamine derivative (TPA-NH 2 ). Under ultrasonic treatment, 1.16 g TPA-NH 2 and 1.1 g WS-CS can be conjugated by 0.7 g HCCP at room temperature. The obtained copolymer shows amphiphilic property and could assemble into nanoparticles with size about 100 nm. After self-assembly, TPA-NH 2 was aggregated in the core, thus exhibiting superb AIE feature with intense green fluorescence emission in aqueous media. On the other hand, hydrophilic WS-CS was coated on the surface of nanoparticles and endowed their high water dispersibility. Results from preliminary biological assays suggested that WS-CS-TPA can be internalized by cells and exhibits low cytotoxicity, suggesting their great potential for biological imaging and intracellular drug delivery.

Thermal and mechanical performance of electrospun chitosan/poly(vinyl alcohol) nanofibers with graphene oxide

Yang Shuai,Liu Yongxu,Jiang Zaixing,Gu Jiyou,Zhang Dawei

In this paper, electrospun chitosan (CS)/poly(vinyl alcohol) (PVA)/graphene oxide (GO) nanofibers were fabricated. Prepared nanofibers have been characterized and investigated for their morphological, structural, and thermal stability, and mechanical and hydrophilic properties. The uniform and defect-free nanofibers were obtained and GO, shaping spindle and spherical, was partially embedded into nanofibers, as shown in SEM. The hydrogen bonds between CS molecules and PVA molecules were easily formed due to the great compatibility of CS and PVA. The addition of GO interrupted the hydrogen bonds between CS molecules and PVA molecules, and the new interaction was formed among CS, PVA, and GO. Thermogravimetric analysis indicated that as the increasing of content of GO, the thermal stability of nanofibers decreased. More interestingly, the static mechanical properties tests and dynamic mechanical analysis all showed that the modulus of nanofibrous mats increased firstly and decreased subsequently with the increasing of content of GO, which could be concerned with the looser arrangement of nanofibers. The water contact angle of nanofibrous mats increased with the increasing of content of GO. Nevertheless, when the content of GO was up to 2.5 wt%, the water contact angle decreased significantly. ᅟ

Preparation of bio-based polyamide 56/chitosan heavy metal adsorbing nanocomposite fibers by electrospinning

Yuhan Xu,Jinheng Wang,Chenyan Zhang,Jikui Wang,Weihong Guo

Electrospinning technology can produce nanofibers with extremely high specific surface area. Bio-based polyamide 56 (PA56) was combined with chitosan (CS) to prepare PA56/CS composite nanofibers. An in vitro mineralization experiment was conducted to obtain a super hydrophilic composite fiber (PA56/CS-HAP) with hydroxyapatite deposited on the surface. The adsorption performance of the composite fiber (PA56/CS-HAP) was evaluated by the adsorbent dosage, solution pH value, and adsorption kinetics. The curves obtained after fitting the kinetics and adsorption isotherms show that the adsorption behavior under pH = 6 is more consistent with the Langmuir adsorption model. The adsorption capacity in a 100 mg L −1 Pb 2+ environment is more than 5 times that of 10 mg L −1 . Bio-based PA56/CS static-spun nanocomposite fibers prepared by in vitro mineralization have great potential in environmental protection, sensors, chemical engineering, and other fields. Highlights PA/CS fibers were prepared by electrospinning. Hydroxyapatite was deposited by in vitro mineralization technique. PA/CS-HAP fiber achieves super hydrophilic effect. The adsorption capacity of PA/CS-HAP in 100 mg L −1 Pb(II) reached 27.5 mg g −1 . After fitting, the adsorption process is consistent with Langmuir adsorption.

Study on nano-chitosan grafting quaternary ammonium salt modified polyacrylamide for flocculation and sterilization

Zheng Zhong,Fengjiao Zhang,Wei Chen,Xiaguo Wei,Yiwen Zhang,Yanbo Lu,Hongbin Luo,Liangqian Fan

ABSTRACT A dual-function chitosan-based flocculant named nano-chitosan-graft-poly(acrylamide and acryloyloxyethyltrimethyl ammonium chloride (NCS-g-P(AM-DAC)) with flocculation and sterilization properties was successfully synthesized by using nano-chitosan (NCS), acrylamide, and acryloyloxyethyltrimethyl ammonium chloride (DAC) under ultraviolet irradiation with 2,2’-Azobis(2- methylpropionamidine) dihydrochloride as the photo-initiator. NCS was obtained via ion cross-linking between chitosan and sodium tripolyphosphate. The structure and physicochemical properties of the product were characterized by various methods. The influence of different factors on the intrinsic viscosity of synthetic copolymer was investigated to optimize the synthetic condition. The flocculation performance of NCS-g-P(AM-DAC) was evaluated. Results showed that the superior flocculation efficiency was acquired under pH = 6 and flocculant dosage of 5 mg L –1 , in which turbidity removal efficiency was above 85%. Considering that the quaternary ammonium salt was grafted and the nanoparticle generated, NCS-g-P(AM-DAC) was also applied to flocculate Escherichia coli (E. coli) suspension to evaluate the sterilization performance. At suitable dosage and pH conditions, the flocculant effectively removed turbidity and bacterial cells. 3D fluorescence spectroscopy analysis of E. coli suspension after the flocculation was conducted to investigate the sterilization mechanism. The results showed that NCS-g-P(AM-DAC) could destroy cell membranes, indicating its bactericidal, not simply antibacterial, effect during flocculation.

A Study of Adsorption Behaviour of Cu(II) on Hydroxyapatite-Coated-Limestone/Chitosan Composite

Peng Xilong,Li Yue,Liu Shuang,Jiang Tian,Chen Wenjin,Li Dan,Yuan Jiren,Xu Feigao

In this experiment, chitosan (CS), waste limestone and diammonium hydrogen phosphate were used as raw materials to synthesize HAp-coated-stone composites/CS by one-step blending method. Then, the prepared HAp-coated-stone composites/CS composite material was used to remove Cu (II) in the solution. The structure and microstructure of the composite were characterized by Fourier transform infrared spectroscopy, X-ray diffraction analysis, Scanning Electron Microscopy, Brunauer–Emmett–Teller and Thermogravimetric Analysis. The results showed that with the addition of CS, the overall thermal stability of the composite improved, while its specific surface area decreased. Moreover, the composite was a mesoporous material. HAp-coated-stone/CS composites with small amounts of CS (0.5%) can remarkably increase Cu (II) removal. The HAp-coated-limestone/CS-0.5% had better resistance to pH changes compared with HAp-coated-limestone. Under the initial concentration of 20 mg/L, the maximum adsorption capacity for Cu (II) adsorption by HAp-coated-limestone/CS-0.5% was about 130.75 mg/g at 40 °C. The equilibrium data and kinetic were well described by Freundlich models and pseudo-second-order, respectively. The possible mechanisms for Cu (II) adsorption onto HAp-coated-stone/CS composites surface have been proposed.