查找使用阿拉丁产品的科研文献

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.

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.

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.

Development of propolis extract-loaded nanoparticles with chitosan and hyaluronic acid for improving solubility and stability

Do Hee Kim,Eun Woo Jeong,Youjin Baek,Hyeon Gyu Lee

Propolis extract (PE) is a natural polyphenol with various biological activities; however, its application is limited due to low solubility and instability. To overcome these drawbacks, we encapsulated PE in nanoparticles (PE-loaded nanoparticles, PE-NP) using chitosan (CS) and hyaluronic acid (HA) as wall materials. We examined the physicochemical characteristics (size, polydispersity index, zeta potential, and entrapment efficiency) of PE-NP prepared with the various ratios of CS to HA and core to the wall material, and confirmed the optimal ratio for the formulation of PE-NP as 4:7 and 1:2, respectively. In addition, PE-NP significantly increased the solubility of PE by 2.43-fold compared to that of free PE ( p  < 0.05). Moreover, the retention rate of total flavonoid content (TFC) in PE-NP was significantly higher than that in free PE after the heat treatment (90 °C) for 24 h ( p  < 0.05). Furthermore, PE-NP showed significantly higher retention rates of TFC and DPPH radical scavenging effects than free PE after storage for 4 weeks at 30 and 50 °C ( p  < 0.05). In conclusion, these findings suggest that PE-NP may be a promising approach to enhance the solubility and stability of PE and could provide helpful information for expanding the application of PE.

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.

Softening and enriching polarity of chitosan backbone as a bifunctional binder for high-performance sulfur cathode

Sai-Sai Deng,Li Deng,Zong-Kui Liu,Jun-Ke Liu,Jing Zhang,Shi-Jun Xie,Ming-Jia Guo,Yao Zhou,Jun-Tao Li

Lithium-sulfur batteries have attracted much attention because of their high energy density; their long-term stability suffers from the shuttle effect of polysulfides and the volume variation of sulfur during charging and discharging process. Herein, by chemically grafting highly flexible and polar poly(N-aryloylglycamide) (PNAGA) segments onto the linear backbone of the naturally abundant, hard and brittle chitosan, a hyper-branched and 3D-linked aqueous binder was prepared, which has stronger binding strength and is more flexible than the pristine chitosan or the commercial PVDF . Moreover, owing to the presence of affluent diamide groups in the PNAGA branches, the grafted binder demonstrates much better ability for capturing polysulfides. When applied in sulfur cathode, the binder is bifunctionally effective, which can suppress the shuttle behaviors of the polysulfides and well maintain the interfacial intimacy, thus enabling excellent long-term cycling stability. After 300 cycles at 0.2 C, the relevant battery still retains 843.1 mAh g  −   1 , spelling a retention rate 49.4% and 69.6% higher than those using PVDF and the pristine chitosan, respectively; even under a high sulfur loading of 5.2 mg cm −2 , the battery can still operate steadily more than 100 cycles at 0.2 C, maintaining a specific capacity above 620.1 mAh g  −   1 .

A ROS-response hyaluronic acid-coated/chitosan polymer prodrug for enhanced tumour targeting efficacy of SN38

Jianpeng Qin,Meng Sun,Yanli Zhen,Ji Li,Dongkai Wang

Synthesis of carbon disulfide modified chitosan resin and its adsorption properties for palladium(Ⅱ) in wastewater

Liuzhou Chen,Kun Wu,Mohe Zhang,Nengsheng Liu,Chenxi Li,Jiangzhou Qin,Quanlin Zhao,Zhengfang Ye

A novel chitosan resin microsphere (CDCR) adsorbent, which was synthesized by secondary crosslinking and carbon disulfide modification, and was evaluated for its efficacy in recovering palladium from wastewater. The physicochemical properties and adsorption mechanism of CDCR were determined using scanning electron microscope energy dispersive system (SEM-EDS), fourier-transform infrared spectroscopy (FTIR), simultaneous thermal analyzer (TG-DSC), X-ray photoelectron spectroscopy (XPS), etc. The experimental results showed that its saturated adsorption capacity was about 204.34 mg/g. And the adsorption process of Pd(Ⅱ) was found to be in accordance with the pseudo-second-order kinetic model and the Freundlich model. Thermodynamic analysis indicated that the reaction between CDCR and Pd(Ⅱ) was a spontaneous endothermic process. CDCR showed good reusability, maintaining a Pd(Ⅱ) removal efficiency of 99.99% after eight adsorption–desorption cycles. In the multi-ion coexistence solution, CDCR also exhibited excellent selectivity towards Pd(Ⅱ) adsorption. Furthermore, the adsorption of Pd(Ⅱ) by CDCR was primarily attributed to electrostatic interaction with protonated amine groups and complexation with sulfur groups.

Multifunctional hydrogel wound dressing with rapid on-demand degradation property based on aliphatic polycarbonate and chitosan

Qida Zong,Xinxuan Peng,Yan Ding,Huiying Wu,Chang Lu,Jing Ye,Wei Sun,Jinwei Zhang,Yinglei Zhai

The multifunctional hydrogel dressings are effective strategy to treat chronic wounds of diabetes. In addition, the ability of selective degradation on demand to change dressings could provide better patient compliance. Here, an injectable, self-healing hydrogel with rapid degradability on-demand is designed to promote the healing of diabetes wounds. The block copolymer formed by aldehyde modified aliphatic cyclic carbonate monomer with polyethylene glycol (MBP) and chitosan (CS) were crosslinked through the Schiff base bond to obtain a hydrogel with excellent injectability and self-healing ability. Due to the presence of carbonate bonds in MBP, it showed the rapid on-demand degradation characteristics triggered by N -acetylcysteine (NAC). At the same time, gallic acid (GA) was loaded into the hydrogel, giving the hydrogel dressing antioxidant. In vivo and in vitro experiments showed that the hydrogel wound dressing possesses good natures, such as antibacterial, antioxidant, and friendly cell compatibility, which could promote wound healing. Overall, the multifunctional hydrogel wound dressings with rapid on-demand degradation characteristics are more practical for clinical applications.

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.