查找使用阿拉丁产品的科研文献

Chitosan for constructing stable polymer-inorganic suspensions and multifunctional membranes for wound healing

Liangyu Wang,Lin Du,Mengmeng Wang,Xing Wang,Saihua Tian,Yan Chen,Xiaoyue Wang,Jie Zhang,Jun Nie,Guiping Ma

Restricted by the rigid chain structure, chitosan-based materials are very fragile and easy to break up. Herein, a stable and positively charged chitosan/Ti 3 C 2 T x suspension was successfully constructed by adjusting mixing sequence, pH and ratio of chitosan to Ti 3 C 2 T x to prepare a multifunctional membrane (P-CM) with self-standing ability, good flexibility, biocompatibility, excellent photothermal antibacterial properties , and sensitive humidity sensing properties. In the first stage, protonated chitosan acted as sugar coatings was able to be encapsulated on the surface of Ti 3 C 2 T x nanosheets by electrostatic self-assembly, in turn achieving charge reversal of the nanoparticles . In the second stage, chitosan acted as molecular needles to suture the membrane formed by chitosan/Ti 3 C 2 T x particles via vacuum filtration (VAF) with the commercial flexible poly(vinylidene fluoride) (PVDF) membrane. The as-prepared P-CM membrane simultaneously solves the problem of insufficient flexibility of a single component chitosan membrane and the poor bonding between pure Ti 3 C 2 T x membranes and substrate membrane.

Effect of sodium alginate/phosphate-stabilized amorphous calcium carbonate nanoparticles on chitosan membranes

Bin Nie,Hong Wang,Yanwei Zhang,Chaohui Rao,Huifang Wang,Xianghua Gao,Wenfeng Li,Baolong Niu

Biodegradable chitosan (CS) films can meet the demand for sustainable development. However, the performance of pure CS membrane still exists a particular gap compared with the traditional film. Inorganic nanomaterials with the controllable release are added to improve its physical and chemical properties. Herein, a series of CS/phosphate-stabilized amorphous calcium carbonate (CS/ACCP) and CS/sodium alginate/ACCP (CS/Alginate/ACCP) composite films were prepared by the flow method. The effects of ACCP and Alginate/ACCP nanoparticles on the physical and chemical properties of the composite membrane were investigated. The results showed that the composite nanoparticles could significantly improve CS film's compactness, hydrophobicity , and mechanical properties and enhance its ultraviolet (UV) blocking ability, water resistance, and water vapor blocking ability. When the number of nanoparticles was 8%, the mechanical properties of the CS composite membrane reached optimum value, and the comprehensive performance was better. In addition, the controlled-release properties of CS composite membranes were also studied, and the antioxidant, antibacterial, biocompatibility, and fresh-keeping effects of the composite membranes were explored. The results indicated that the CS composite membranes had not only excellent bacteriostatic (72%) properties ( Escherichia coli ) but also presented well fruit preservation (15 days) properties (sugar orange). In particular, the controlled release range of CS composite membrane at 12 h was between 30% and 90%, which provided a theoretical basis for its use as an edible membrane. Therefore, based on ACCP and Alginate/ACCP nanoparticles, CS composite membranes with more excellent application value in the biological field were prepared through further optimization design.

Recovering copper ions from wastewater with chitosan to synthesize lead-free primary explosives

Xuwen Liu,Yan Hu,Caimin Yang,Jiaxin Su,Yinghua Ye,Ruiqi Shen

Chitosan (CTS) is a well-known adsorbent capable of absorbing copper ions . It's also a high-quality biomass carbon source. The carbon skeleton formed by the pyrolysis of CTS has outstanding electrical conductivity , which can help copper azide (CA), a new type of primary explosive that's particularly sensitive to electrostatic stimuli, be more electrostatically safe. The CTS-Cu complex is precipitated by using CTS to adsorb and flocculate copper ions in wastewater. To construct the Cu@carbonized chitosan (CCTS) precursor material, the organic ligands in the CTS-Cu complex are calcined into a porous three-dimensional carbon matrix, and the copper ions are transformed into copper nanoparticles embedded in CCTS. The azide reaction converts copper nanoparticles (CuNPs) into high-energy CA. With its good electrical conductivity, CCTS maintains its framework structure and effectively improves the electrostatic safety of composite energetic materials. CA@CCTS has a CA content of 69.7%, an electrostatic ignition energy (E 50 ) of about 1.19 mJ, and a heat release of 1803.22 J/g. This work takes advantage of CA and CTS's environmental friendliness. CA@CCTS, as a novel lead-free primary explosive, has good electrostatic safety while containing a high proportion of CA.

Carboxymethyl chitosan-grafted polyvinylpyrrolidone-iodine microspheres for promoting the healing of chronic wounds

Jie Yu,Pei Wang,Mengting Yin,Kaiwen Zhang,Xiansong Wang,Bing Han

Durably Antibacterial Cotton Fabric Prepared by a Combination of Betaine and Carboxymethyl Chitosan

Xiao Yuanxiang,Duan Panpan,Shen Guokang,Zheng Weishi,Fu Jiajia,Xu Qingbo,Fu Feiya,Liu Xiangdong

A simple pad-dry-cure modification process is proposed to prepare the antibacterial cotton fabrics with durable antibacterial properties. Two natural antibacterial materials, carboxymethyl chitosan (CMC) and betaine (Bet), were grafted on cotton fiber surface to achieve the goal. FTIR-ATR and XPS results reveal that esterification and amidation reactions have taken place between the CMC, Bet, and the cellulose chains on the surface of cotton fibers. Antibacterial evaluation results confirm the antibacterial capability and the durability of the modified fabrics. The bacterial reduction (BR) rates against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) are higher than 99.99 % and can be kept at a level higher than 95 % even after 20 washing cycles. According to the XRD results presented, the entire modification process wreaks little damage to the crystalline structure of the cotton fabric. Especially, both the water vapor permeability and water absorption capability were improved (371.1 g/m 2 /d and 198 %, respectively) when compared to the original cotton fabric. This work provided a new way to fabricate antimicrobial cotton fabric using bio-based compounds, displaying great application potential in the antibacterial textile industry.

Functionally-Designed Chitosan-based hydrogel beads for adsorption of sulfamethoxazole with light regeneration

Aijiao Zhou,Kai Yang,Xumeng Wu,Guoqing Liu,Tian C. Zhang,Qin Wang,Fan Luo

Adsorption method has been widely used in the removal of emerging contaminants. However, many adsorbents are puzzled by key obstacles for effective and simple regeneration. In this work, the functionally-designed graphitic carbon nitride (g-C 3 N 4 ) embedded chitosan-polyvinyl alcohol composite (g-C 3 N 4 /CS/PVA) hydrogel beads were synthesized for the adsorptive removal of sulfamethoxazole (SMX) from water, and they could be regenerated by light. The adsorption kinetics, isotherm, thermodynamics, and impacting factors were systematically investigated. And the adsorption capacity of the hydrogel for SMX was relatively stable at pH of 4–8, with the maximum adsorption capacities being 5.8 mg g −1 at pH 5. The main adsorption force may be inferred to the electrostatic interactions between SMX and hydrogel beads, and hydrogen bonds between the amino or hydroxyl groups of the hydrogel and the amino of the SMX. The dominance of electrostatic interactions resulted in SMX adsorption being highly dependent on ionic strength. Being irradiated with an ultraviolet lamp for 5 recycles, the hydrogel beads still kept good adsorption capacity. The regeneration behavior was attributed to the photocatalytic degradation of SMX by g-C 3 N 4 . Namely, photocatalytic oxidation reactivated the adsorption sites and increased the release of adsorbed pollutants with improved desorption performance.

Immune-stealth carboxymethyl chitosan-based nanomaterials for magnetic resonance imaging-guided photothermal therapy

Yilin Wang,Wenjie Wang,Xiaoming Wang,Hao Wu,Weifeng Zhao,Changsheng Zhao

Numerous protein-based multifunctional nanomaterials have been studied for biomedical applications. However, the inherent immunogenicity and activation of the complement system of protein-based nanomaterials may cause immunological responses, further leading to hypersensitivity and/or allergic reactions in patients. Herein, carboxymethyl chitosan (CMC) and KMnO 4 are used to develop polysaccharide-based MnO 2 (CM) nanoparticles as facile, effective and low-immunogenicity nanomaterials for magnetic resonance imaging (MRI)-guided photothermal therapy (PTT). As a proof of concept, indocyanine green (ICG) is loaded in the CM nanoplatform to form a CMC-MnO 2 -ICG compound (CMI) for MRI-guided photothermal therapy. In vitro studies show that the proposed CMC-based nanomaterials exhibit excellent hemocompatibility and no significant complement activation . The in vivo biosafety experiments also show that the CMC-based nanomaterials have low immunogenicity and will not cause tissue damage. Moreover, the prepared CMI nanoparticles (NPs) possess outstanding photothermal properties and high longitudinal relaxivity (8.47 mM −1  s −1 ), which achieve successful MRI-guided PTT in tumor-bearing mice. This work draws increasing attention to the hemocompatibility and immunogenicity of high-performance nanoprobes for biomedical applications.

Chitosan-covalent organic framework dual-layer membrane with high efficiency of iodine capture

Luo Ruiqing,Liu Ruihua,Li Yongqiang,Li Yarong,He Chiyang

The main challenge in developing polymer/covalent organic framework (COF) hybrid matrix membrane is to find effective strategies for strongly attaching crystalline COF to the supporting surface as defect-free membrane layers. In this article, we demonstrated for the first time a method for the preparation of a chitosan (CS)/COF mixed matrix dual-layer membrane based on solvothermal synthesis method. A novel surface modification strategy was developed using p-phthalaldehyde as covalent linkers between COF and CS membrane substrate, and then the nitrogen-containing covalent organic framework (NCOF) membrane was further grown in situ on the modified CS membrane substrate utilizing solvothermal synthesis methods. The resultant CS/NCOF dual-layer membrane exhibited highly homogeneous texture due to the excellent compatibility between NCOF crystals and CS matrixes. The combination of NCOF and CS membrane formed a large number of channels in the nitrogen environment, enabling the CS/NCOF dual-layer membrane to have an enhanced iodine uptake capacity up to 3.15 g/g. Furthermore, the CS/NCOF dual-layer membrane could be recycled at least five times while maintaining 95% iodine capture capacity. These properties make the obtained CS/NCOF dual-layer membrane ideal absorbent material for reversible iodine capture. This ingenious dual-layer membrane preparation strategy provides a new avenue to customize synthesis of novel membrane materials for clean energy and environmental remediation. Graphical abstract

Chitosan inhibits advanced glycation end products formation in chemical models and bakery food

Shenwan Wang,Lili Zheng,Xiaoyan Zheng,Yang Yang,Dao Xiao,Haide Zhang,Binling Ai,Zhanwu Sheng

The inhibitory effects of eight common hydrocolloids on the formation of advanced glycation end products (AGEs) were evaluated using chemical models. Among the hydrocolloids, chitosan (CTS) showed the best inhibition of AGEs formation. CTS greatly decreased the concentrations of fluorescent and non-fluorescent AGEs in the models when added at 0.5% (w/w). The effect of CTS was also evaluated in sponge cakes . Addition of 0.5% (w/w) CTS to the cake batter, decreased AGEs by 30.31%–61.22% and improved the hardness and moisture content of the cake without changing the color. The contents of N ε -carboxymethyllysine and the N ε -carboxyethyllysine in the free state were reduced by 51.68% and 42.43%, respectively. The inhibition mechanism of CTS was studied and we found that CTS decreased the availability of substrate of glycation by reacting with protein and competing reducing sugars with lysine and arginine in the chemical models. This resulted in inhibition of proteins oxidation and retarded the reaction between dicarbonyl compounds and proteins. The results of this study indicate that CTS is a potential inhibitor of AGEs formation for use in baked products.

Chitosan Based Aerogels with Low Shrinkage by Chemical Cross-Linking and Supramolecular Interaction

Sizhao Zhang,Qi Xiao,Yunyun Xiao,Zhengquan Li,Shixian Xiong,Feng Ding,Junpeng He

Chitosan (CTS) aerogel is a new type of functional material that could be possibly applied in the thermal insulation field, especially in energy-saving buildings. However, the inhibition method for the very big shrinkage of CTS aerogels from the final gel to the aerogel is challenging, causing great difficulty in achieving a near-net shape of CTS aerogels. Here, this study explored a facile strategy for restraining CTS-based aerogels’ inherent shrinkage depending on the chemical crosslinking and the interpenetrated supramolecular interaction by introducing nanofibrillar cellulose (NFC) and polyvinyl alcohol (PVA) chains. The effects of different aspect ratios of NFC on the CTS-based aerogels were systematically analyzed. The results showed that the optimal aspect ratio for NFC introduction was 37.5 from the comprehensive property perspective. CTS/PVA/NFC hybrid aerogels with the aspect ratio of 37.5 for NFC gained a superior thermal conductivity of 0.0224 W/m·K at ambient atmosphere (the cold surface temperature was only 33.46 °C, despite contacting the hot surface of 80.46 °C), a low density of 0.09 g/cm3, and a relatively high compressive stress of 0.51 MPa at 10% strain.Keywords:chitosan aerogels;shrinkage;nanofibrillar cellulose;mechanical property;thermal insulation

Synergistic photodynamic/photothermal bacterial inactivation over heterogeneous quaternized chitosan/silver/cobalt phosphide nanocomposites

Hecheng Han,Xiaoying Xu,Haopeng Kan,Yunxiang Tang,Chang Liu,Hongling Wen,Lili Wu,Yanyan Jiang,Zhou Wang,Jiurong Liu,Fenglong Wang

Globally, drug-resistant bacteria are a potential threat to human society owing to the overuse of antibiotics and thus, non-antibiotic bactericides are urgently needed. Herein, an innovative antibacterial nanoplatform based on quaternized chitosan (QCS)/ silver (Ag)/ cobalt phosphide (CoP) nanocomposites is envisaged for achieving near-infrared (NIR) laser-inducible rapid sterilisation. In the core-shell hybrids, Ag nanoparticles (NPs) with a size of ∼ 25 nm were uniformly deposited on CoP nanoneedles , upon which a layer of QCS (approximately 10 wt%), is coated. Numerical calculations revealed that under NIR irradiation, high-energy hot electrons arising from the surface plasmon resonance effect of Ag migrate into the interface between Ag and CoP, and amplify the photothermal effect of CoP. Meanwhile, photo-excited electrons from CoP are transported onto Ag NPs because the Schottky heterostructure facilitates the production of reactive oxygen species . Ag loading simultaneously enhances the photocatalytic and photothermal effects of CoP, achieving rapid antibacterial activity synergistically. The QCS coating improves the dispersibility of power in an aqueous system and provides contact between the antiseptics and bacteria. The ternary QCS/Ag/CoP nanocomposites achieved greater than 99.6% inactivation against S. aureus and E. coli within 10 min. In addition, the nanocomposites were confirmed to be noncytotoxic to mammals. Consequently, the QCS/Ag/CoP nanoplatforms possess great potential for rapid and effective antibacterial applications.

Photodynamic Effect of Riboflavin on Chitosan Coatings and the Application in Pork Preservation

Jiliu Pei,Shengyu Zhu,Yu Liu,Yukang Song,Feng Xue,Xiaohui Xiong,Chen Li

Riboflavin (RF) was considered to be possessed of photoactivity to generate reactive oxygen species (ROS) under ultraviolet (UV) light, which is thought to be a favorable antibacterial candidate. Herein, RF was incorporated into chitosan (CS) coatings and treated under UV with different exposure times (2, 4, and 6 h) to improve the physicochemical and antibacterial properties. The results showed that the light transmittance and antibacterial performance of chitosan coatings gradually increased with the extension of the UV irradiation time. The antibacterial ability of chitosan coatings correlated with the generation of ROS: ∙OH and H2O2, which achieved 1549.08 and 95.48 μg/g, respectively, after 6 h irradiation. Furthermore, the chitosan coatings with UV irradiation also reduced the pH value, total volatile basic nitrogen (TVB-N), ΔE, and total viable counts (TVC) and improved sensory attributes of pork. In conclusion, the UV irradiated chitosan coatings could be used as an environmentally friendly antimicrobial packaging material to effectively delay the spoilage of pork, maintain its sensory quality and prolong its shelf life.Keywords:chitosan;riboflavin;UV irradiation;pork preservation;antibacterial activity