查找使用阿拉丁产品的科研文献

Resveratrol-loaded selenium/chitosan nano-flowers alleviate glucolipid metabolism disorder-associated cognitive impairment in Alzheimer's disease

Licong Yang,Yabin Wang,Guodong Zheng,Zhiwei Li,Jingtao Mei

Resveratrol (Res) is a common natural polyphenol that inhibits inflammation and oxidative stress in Alzheimer's disease (AD). However, the absorption efficiency and in vivo bioactivity of Res are poor. High fat diet-induced metabolic disorders, including obesity and insulin resistance, can promote AD-related β-amyloid (Aβ) aggregation, Tau protein phosphorylation and neurotoxicity. Gut microbiota play a role in modulating metabolic syndrome and cognitive impairment. Herein, flower-like Res-loaded selenium nanoparticles/chitosan nanoparticles ( [email protected] @Res-CS-NPs) with higher loading capacity (64 %) were prepared to regulate gut microbiota in cases of AD with metabolic disorder. The nano-flowers could restore gut microbiota homeostasis to reduce lipopolysaccharide (LPS) formation and LPS-induced neuroinflammation. Additionally, [email protected] @Res-CS-NPs can prevent lipid deposition and insulin resistance by decreasing Firmicutes levels and increasing Bacteroidetes levels in the gut, further inhibiting Aβ aggregation and Tau protein phosphorylation through the JNK/AKT/GSK3β signaling pathway. Moreover, [email protected] @Res-CS-NPs treatment was able to regulate the relative levels of gut microbiota associated with oxidative stress, inflammation and lipid deposition, including Entercoccus , Colidextribacter , Rikenella , Ruminococcus , Candidatus_Saccharimonas , Alloprevotella and Lachnospiraceae_UCG-006 . Overall, [email protected] @Res-CS-NPs significantly enhances cognitive ability in AD mice with metabolic disorder, highlighting their potential for preventing cognitive impairments in AD.

Adsorption of Th(IV) on glutaraldehyde cross-linked N-(4-Aminobenzoyl)-ʟ-glutamic acid modified chitosan

Luo Qingyun,Wang Chongshi,Zhu Wei,Yu Hongchao,Wang Chunyan,Chen Chuanhong

Due to its high adsorption capacity and adsorption efficiency, polymer gel shows excellent performances in the treatment of wastewater containing thorium. In this work, glutaraldehyde cross-linked N -(4-Aminobenzoyl)-ʟ-glutamic acid modified chitosan (CCS-AGA) was used to adsorb Th(IV) ions from aqueous solutions for the first time. FT-IR and SEM results revealed the chemical structure and surface morphology of this material. The influence of solution pH, contact time and initial concentration of Th ions on the adsorption of Th(IV) by CCS-AGA was investigated. The experimental data suggest that the adsorption behavior of CCS-AGA could be accurately predicted by the Langmuir model. The maximum theoretical adsorption capacity of CCS-AGA for Th(IV) was 162 mg/g. Moreover, this material exhibited excellent reusability and adsorption selectivity for Th(IV).

Adsorption of chitosan combined with nicotinamide-modified eupatorium adenophorum biochar to Sb3+: Application of DFT calculation

Pengyang Bian,Bei Gao,Junhao Zhu,Huimin Yang,Yue Li,Ermao Ding,Yixuan Liu,Yaxing Liu,Shichen Wang,Weibo Shen

The pollution and harm of Sb 3+ to aquatic systems is a global problem, so Sb 3+ removal from the water environment to make sure environment safety and human beings wellbeing is of urgency. This study explored the effect of chitosan combined with nicotinamide-modified eupatorium adenophorum biochar (CEBC) on adsorbing Sb 3+ through batch adsorption experiments. The experiments indicated CEBC's maximum adsorption capacity to Sb 3+ is 170.15 mg·g −1 . Meanwhile, the capacity of the original biochar (EBC) is only 9.97 mg·g −1 . Compared with EBC, CEBC contains more functional groups, such as C O, -OH and -NH 2 . In addition, the pseudo-second-order kinetic model and the Langmuir model are fit to describe the kinetics and isotherms of adsorption of CEBC to Sb 3+ , which suggests that the adsorption of CEBC to Sb 3+ is dominated by monolayer chemisorption. Density functional theory (DFT) calculations confirmed that the chelation between –NH 2 and Sb 3+ is of significance in the adsorption process of CEBC. DFT calculations also found that the newly added –OH and C O in EBC have a synergistic enhancement effect on the absorption of Sb 3+ . The mechanism of CEBC absorbing Sb 3+ includes electrostatic interactions, pore filling, Л–Л interactions, hydrogen bonding, functional group complexation, chelation, and oxidation . CEBC has an excellent anti-interference ability for inorganic anions (NO 3 − , SO 4 2− and Cl − ) and can also use the coexisting HA to improve its adsorption performance. In addition, CEBC has better mitigation of Sb 3+ on the performance of Sb 3+ about its secondary release and good reproducibility, which indicates that CEBC is a viable Sb 3+ adsorbent.

Long-term antibacterial activity by synergistic release of biosafe lysozyme and chitosan from LBL-structured nanofibers

Jun Wu,Fangtian Liu,Chaoji Chen,Ze Zhao,Yumin Du,Xiaowen Shi,Yang Wu,Hongbing Deng

Biosafe antibacterial agents are urgently demanded in treating infection especially chronic infection. However, efficient and controlled release of those agents remains great challenging. Two nature-derived agents, lysozyme (LY) and chitosan (CS), are selected to establish a facile method for long-term bacterial inhibition. We incorporated LY into the nanofibrous mats, then deposited CS and polydopamine (PDA) on the surface by layer-by-layer (LBL) self-assembly. In this vein, LY is gradually released with the degradation of nanofibers , and CS is rapidly disassociated from the nanofibrous mats to synergistically result in a potent inhibition against Staphylococcus aureus ( S. aureus) and Escherichia coli ( E. coli) over a period of 14 days. Besides long-term antibacterial capacity, LBL-structured mats could readily achieve a strong tensile stress of 6.7 MPa with an increase percentage of up to 103%. The enhanced proliferation of L929 cells arrives at 94% with help of CS and PDA on the surface of nanofibers. In this vein, our nanofiber has a variety of advantages including biocompatibility, strong long-term antibacterial effect , and skin adaptability, revealing the significant potential to be used as highly safe biomaterial for wound dressings.

Preparation of boron-containing chitosan derivative and its application as intumescent flame retardant for epoxy resin

Wang Junjie,Chen Jinhao,Wang Wenwen,Lu Jing,Li Yingying,Bai Ting,Chen Jiahui,Zhu Zongmin,Wang Dong

A new boron-containing chitosan-based compound HBS was synthesized and used in combination with ammonium polyphosphate (APP) as an efficient flame retardant with good compatibility for epoxy resin. The modified EP composites were investigated by thermogravimetric analysis (TGA), UL-94 V (vertical burning), limited oxygen index (LOI) and cone calorimetry (CC) test. The sample labeled S3 with the total addition of HBS and APP was 10%, simultaneously the weight ratio of HBS and APP was 1:3, which passed the UL-94 V-0 rating. LOI value of sample S3 was 30.5%, which was higher than that of EP (S0, 22.6%) and EP modified with 10% APP (S5, 26.1%). CC tests results showed that PHRR (peak heat release rate), THR (total heat release), PSPR (peak smoke production rate) and TSP (total smoke production) values of sample S3 were 515.9 kW/m 2 , 50.6 MJ/m 2 , 0.14 m 2 /s and 10.9 m 2 , respectively, which were 51.5, 33.5, 74.5 and 84.7% lower than those of unmodified EP, respectively. What’s more, flame retardancy parameters such as fire index growth rate (FIGRA), maximum average rate of heat emission (MARHE) and average effective heat of combustion (av-EHC) also decreased. The char residue of sample S3 was 61.3%, which was 506.9% higher than that of EP. The introduction of HBS and APP was beneficial to form a sufficient, dense, homogeneous and high strength char layer on the EPs surface during combustion. Due to the effective protective layer, the transfer and diffusion of heat can be effectively inhibited, the production of combustible gases can be restricted, and the emission of smoke can be inhibited, thus reducing the release of heat and smoke.

Efficient adsorption of arsenic in groundwater by hydrated iron oxide and ferromanganese oxide chitosan gel beads

Yiqun Liu,Liuke Cai,Xiaoyu Wang,Zhihao Chen,Wenzhong Yang

To address the arsenic contamination in groundwater, the hydrated iron oxide gel beads (CS-HFO) and iron manganese oxide gel beads (CS-FMO) adsorbents were prepared. The CS-HFO and CS-FMO adsorbents had porous and adsorption-friendly pore structures inside, with the average pore sizes of 3.45 nm and 7.78 nm, respectively. As compared to the CS-HFO adsorbent, the CS-FMO adsorbent had rich adsorption sites and oxidation capacity and displayed better adsorption performance. According to the Langmuir model, the saturation adsorption of As(V) and As(III) for CS-FMO adsorbent was calculated as 26.65 mg/g and 35.96 mg/g, respectively. After 10 cycles of regeneration, the CS-HFO and CS-FMO adsorbents demonstrated excellent sustainable arsenic removal ability, while the adsorption efficiencies of CS-FMO adsorbent for As(V) and As(III) were maintained over 60 % and 95 %, respectively. In addition, the competing pollutants and fixed-bed column experiments confirmed the high selectivity of the CS-HFO and CS-FMO adsorbents, which showed great promise for the future application of arsenic contamination removal from the actual groundwater environment.

Osteochondral repair using scaffolds with gradient pore sizes constructed with silk fibroin, chitosan, and nano-hydroxyapatite

Hongli Xiao,Wenliang Huang,Kun Xiong,Shiqiang Ruan,Cheng Yuan,Gang Mo,Renyuan Tian,Sirui Zhou,Rongfeng She,Peng Ye,Bin Liu,Jiang Deng

One-pot method of recyclable lipase-nanocatalyst based on chitosan magnetic nanomaterial for ethyl levulinate synthesis

Ge Tang,Kuaqian Deng,Panyang Li,Jiali Huang,Fanglin Dao,Hao Jiang,Jing Wang,Jianfang Jiang

Carrier, immobilization method and conditions are the most important factors affecting the performance of immobilized lipase . In this study, [email protected] is successfully prepared via an improved hydrothermal method combined with ion condensation. Then, we creatively adopt one-pot method, combining electrostatic adsorption with chemical crosslinking , to prepare lipase-nanocatalyst with excellent performance under mild conditions. [email protected] and lipase-nanocatalyst are characterized by FTIR, SEM, HRTEM , CLSM, CD, etc, the optimal conditions are explored in detail too. Lipase-nanocatalyst is 189 nm, and the loading ratio of free lipase is up to 67.6%. Compared with free lipase, specific activity is increased by 2.9 times, and it also broadens toleration to pH, thermal, organic solvents . In addition, lipase-nanocatalyst exhibits high storage stability and reusability . The residual activity is approximately 92.3% after the 10th recycle, and the cumulative catalytic activity is 13.4 times than that of free lipase. Finally, lipase-nanocatalyst is used to synthesize ethyl levulinate, with a production ratio of 68.6% for the first recycle, and the total output of EL is 12.9 times than that of free lipase after ten cycles. Thus, our findings provide a foundation for lipase-nanocatalyst showing several attractive features, such as easy preparation, excellent catalytic activity, good stability and reusability.

Incorporating Portulaca oleracea extract endows the chitosan-starch film with antioxidant capacity for chilled meat preservation

Xiaojing Fan,Bin Zhang,Xing Zhang,Zhiqing Ma,Xianchao Feng

This study aimed to investigate the application potential of Portulaca oleracea extract (POE) in active packaging for the preservation of chilled meat. First, the antioxidant capacity and active ingredients of POE were systematically studied. The results demonstrated that POE has excellent antioxidant capacity and contains abundant antioxidant compounds. Subsequently, antioxidant-active packaging films based on chitosan and starch containing different concentrations of POE (CS/POE films) were successfully developed. The main physicochemical and mechanical properties of the CS/POE films were characterized and evaluated. The CS/POE films exhibited remarkable antioxidant activity and can significantly reduce lipid oxidation in meat. Compared with polyethylene film, the CS/POE films-treated meats had better preservation effects and longer shelf-life. These findings suggested that CS/POE film has the potential to become a good alternative to conventional plastics in food packaging. In conclusion, Portulaca oleracea extract is an excellent natural antioxidant with great potential in active packaging for chilled meat preservation.

Construction of chitosan-based supramolecular biofilm material for wound dressing based on natural deep eutectic solvents

Xiangyu Sun,Jiaming Yu,Qifeng Wei,Xiulian Ren

Bacterial infection is still one of the main problems observed in the clinical process of wound healing, so the development of new multifunctional biocompatible materials is an urgent clinical need. A kind of supramolecular biofilm crosslinked by hydrogen bond between natural deep eutectic solvent and chitosan was studied and successfully prepared to reduce bacterial infection. Its killing rates of Staphylococcus aureus and Escherichia coli can reach 98.86 % ± 1.90 % and 99.69 % ± 0.53 %, and it can be degraded in both soil and water, showing excellent biocompatibility and biodegradability . In addition, the supramolecular biofilm material also has the UV barrier property, which can effectively avoid the secondary injury of UV to the wound. Interestingly, the cross-linking effect of hydrogen bond makes the biofilm have a more compact structure and rough surface, and gives the biofilm strong tensile properties. Overall, owing to these unique advantages, NADES-CS supramolecular biofilm has great potential for medical applications, laying the foundation for the realization of sustainable polysaccharide materials.

Covalently polysaccharide-based alginate/chitosan hydrogel embedded alginate microspheres for BSA encapsulation and soft tissue engineering

Lian Xing,Jinchen Sun,Huaping Tan,Guoliang Yuan,Jianliang Li,Yang Jia,Dangsheng Xiong,Guang Chen,Jianzhong Lai,Zhonghua Ling,Yong Chen,Xiaohong Niu

Hydrogels based scaffolds are very promising materials for a wide range of medical applications including tissue engineering and drug delivery. This study reports a covalently cross-linked composite hydrogel embedded with microspheres basing natural polysaccharides as a protein delivery system for soft tissue engineering. This biodegradable composite hydrogel derived from water-soluble chitosan and alginate derivatives upon mixing, without addition of chemical cross-linking agents. The gelation is attributed to the Schiff-base reaction between amino and aldehyde groups of N -succinyl chitosan ( N -Chi) and oxidized alginate (OAlg), respectively. Meanwhile, gel-like microspheres were prepared with a diameter of 2–10 μm by conjugating sodium alginate with Ca 2+ in an aqueous emulsion via the emulsion cross-linking technique. Bull Serum Albumin (BSA) was encapsulated into alginate gel microspheres and subsequently incorporated into OAlg/ N -Chi hydrogels to produce a composite scaffold. In the current work, gelation rate, morphology, mechanical properties, swelling ratio, in vitro degradation and BSA release of the composite scaffolds were examined. The results show that mechanical and stable properties of gel scaffolds can be significantly improved by embedding alginate microspheres. The alginate microspheres can serve as a filler to toughen the soft OAlg/ N -Chi hydrogels. Compressive modulus of composite gel scaffolds containing 0.5 mL volume of microspheres was 57.3 KPa, which was higher than the control hydrogel without microspheres. Moreover, the controlled release of BSA encapsulated within this composite hydrogels showed significantly lower rate when compared with control hydrogel or microspheres alone. These characteristics provide a potential opportunity to use this injectable composite gel scaffold in protein delivery and soft tissue engineering applications.

Chitosan Oligosaccharides Induce Apoptosis in Human Renal Carcinoma via Reactive-Oxygen-Species-Dependent Endoplasmic Reticulum Stress

Xingchen Zhai,Shoujun Yuan,Xin Yang,Pan Zou,Linna Li,Guoyou Li,Yong Shao,A. M. Abd El-Aty,Ahmet Hacımüftüoğlu,Jing Wang

In recent years, various studies have confirmed the role of natural products as effective cancer prevention and treatment drugs. The present study demonstrated that chitosan oligosaccharide (COS) from shells of shrimp and crab caused an inhibitory effect on the proliferation of human renal carcinoma in vitro and in vivo. First, the in vivo biodistribution of COS was investigated by the synthesis of cyanine-7-labeled COS (COS–Cy7) following tail vein injection. The kidney was found to be a major target organ. Then, the impacts on renal carcinoma cell proliferation, apoptosis, and reactive oxygen species (ROS) production were observed in vitro, and an orthotopic xenograft tumor model was designed to evaluate the antitumor efficacy of COS in vivo. In renal carcinoma cells, COS induced G2/M phase arrest and apoptosis in a ROS-dependent fashion. COS significantly promoted mRNA expression of nuclear factor erythroid 2-related factor (Nrf2) and Nrf2 target genes, such as heme oxygenase 1, modifier subunit of glutamate cysteine ligase, and solute carrier family 7 member 11. Additionally, COS significantly upregulated the protein expression of glucose-regulated protein 78, protein RNA-like endoplasmic reticulum (ER) kinase, eukaryotic initiation factor 2α, activating transcription factor 4, C/EBP homologous protein, and cytochrome c, which justified the activation of the ER stress signaling pathway. In vivo, COS repressed tumor growth and induced apoptosis and ROS accumulation, consistent with the in vitro results. Taken together, COS repressed human renal carcinoma growth and induced apoptosis both in vitro and in vivo, mainly via ROS-dependent ER stress pathways.