查找使用阿拉丁产品的科研文献

Evaluation of the PEG Density in the PEGylated Chitosan Nanoparticles as a Drug Carrier for Curcumin and Mitoxantrone

Yao Chen,Di Wu,Wu Zhong,Shuwen Kuang,Qian Luo,Liujiang Song,Lihua He,Xing Feng,Xiaojun Tao

Polyethylene glycolated (PEGylated)curcumin-grafted-chitosan (PCC) conjugates were synthesized with three PEG/chitosan feed molar ratios (1/5, 1/7.5, and 1/10), namely PCC1, PCC2 and PCC3. Chemical structures of these conjugates were characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR). The degrees of substitution (DS) of PEG were 0.75%, 0.45% and 0.33%, respectively, for PCC1, PCC2 and PCC3by1H NMR analysis. Self-assembled PCC nanoparticles (NPs) were spherical as observed in transmission electron microscope images. Mitoxantrone (MTO)-loaded PCC NPs were prepared to analyze the particle size, zeta potential, drug loading, drug release and in vitro cytotoxicity. The MTO-loaded PCC3 NP (DS = 0.33%) possessed the smallest size (~183.1 nm), highest zeta potential (~+34.0 mV) and the largest loading capacity of curcumin (CUR, ~16.1%) and MTO (~8.30%). The release results showed that MTO-loaded PCC3 NP demonstrated the lowest percentage of MTO release and increased as pH decreased, but the CUR release could only be detected at pH 4.0. In the cytotoxicity study, MTO-loaded PCC3 NP displayed the highest cytotoxicity in HepG2 cell line and the best synergistic effect among the tested NPs. Our results suggest that the DS of PEG has impacts on the structures and functions of PCC NPs: the smaller DS of PEG was associated with the smaller size, the higher zeta potential, the slower drug release, and the higher cytotoxicity of NPs.Keywords:curcumin;mitoxantrone;synergism;PEG;chitosan nanoparticles

Methyl jasmonate-loaded chitosan nanoparticles improve tea drought resistance: A case study on drought-sensitive cultivar ‘Zhongcha 108’

Abdelkader Bassiony,Mengxue Zhou,Qunhua Peng,Ying Wang,Guanhua Liu,Jiaqi Yang,Kangni Yan,Dan Mu,Jianyu Fu,Haipeng Lv,Zhi Lin,Jiang Shi

DS severely impacts tea plant growth and yield. Foliar application of Methyl jasmonate (MJ) -loaded Chitosan nanoparticles (CNPs) (MJ-CNPs) significantly boost tea DS resistance, necessitating further mechanism exploration. This study comprehensively investigated alterations at the phenotypic, biochemical, and genetic levels. Relative water content, total pigment content, and soluble proteins decreased, while soluble sugar increased significantly under DS and with apparent recovery after MJ-CNPs treatment. Catechins exhibited a significant decrease under DS, especially EGCG (24.6 to 13.4 mg•g −1 ), but were absolutely mitigated by treatment. Antioxidant capacities (DPPH, FRAP, ABTS, and SOA) showed a further improvement by MJ-CNPs treatment. Endogenous ABA and SA increased under DS, further elevated by MJ-CNPs. CsNCED, CsPYL8, CsPP2C, CsMYB, and CsABF genes involved in ABA-dependent pathways were confirmed with promoted expressions by foliar pre-treatment. The CsJAZ and CsMYC2 gene family which involved in the jasmonic acid (JA) pathway, displayed varied expression patterns. The integration of metabolite and gene expression levels provided a comprehensive illustration of tea DS tolerance mechanism and offered promising promotion strategies through foliar application of MJ-CNPs.

Co-immobilization of laccase and ABTS onto amino-functionalized ionic liquid-modified magnetic chitosan nanoparticles for pollutants removal

Xiang Qiu,Shushu Wang,Shanshan Miao,Hongbo Suo,Huajin Xu,Yi Hu

This work aims to achieve the co-immobilization of laccase and 2,2-binamine-di-3-ethylbenzothiazolin-6-sulfonic acid (ABTS) to improve removal capability of the biocatalyst for pollutants while avoiding potential pollution caused by ABTS. The laccase was immobilized on magnetic chitosan nanoparticles modified with amino-functionalized ionic liquid containing ABTS (MACS-NIL) based on Cu ion chelation (MACS-NIL-Cu-lac). The carrier was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, x-ray diffraction and etc., and electron paramagnetic resonance confirmed the mediator molecule ABTS on the carrier could also play the role of electron transmission. MACS-NIL-Cu-lac presented relatively high immobilization capacity, enhanced activity (1.7-fold that of free laccase), improved pH and temperature adaptability, and increased thermal and storage stability. The removal performance assay found that MACS-NIL-Cu-lac had a good removal efficiency with 100.0 % for 2,4-dichlorophenol in water at 25 °C, even when the concentration reached 50 mg/L. Reusability study showed that after six catalytic runs, the removal efficiency of 2,4-dichlorophenol by MACS-NIL-Cu-lac could still reach 93.2 %. Additionally, MACS-NIL-Cu-lac exhibited higher catalytic efficiencies with 100.0 %, 70.5 % and 93.3 % for bisphenol A, indole, and anthracene, respectively. The high catalytic performance in pure water system obtained by the novel biocatalyst co-immobilizing laccase and electron mediator ABTS showed greater practical application value.

Separation and extraction of Co(II) using magnetic chitosan nanoparticles grafted with β-cyclodextrin and determination by FAAS

Moghimi Ali

A novel and selective method for the fast determination of trace amounts of Co(II) ions in water samples has been developed. The procedure is based on the selective sorption of Co(II) ions using magnetic chitosan nanoparticles grafted with β-cyclodextrin at different pH followed by elution with organic eluents and determination by atomic absorption spectrometry The preconcentration factor was 100 (1 mL elution volume) for a 100 mL sample volume. The limit of detection of the proposed method is 1.0 ng mL −1 . The maximum sorption capacity of sorbent under optimum conditions has been found to be 5 mg of Co per gram of sorbent. The relative standard deviation under optimum conditions was 3.0% ( n = 10). Accuracy and applicability of the method was estimated using test samples of natural and model water with different amounts of Co(II).

Honokiol-Loaded β-D-Glucan/Chitosan Nanoparticles with Antibacterial and Anti-Inflammatory Activities for Promoting MRSA-Infected Wound Healing

Background:Methicillin-resistantStaphylococcus aureus(MRSA) wound infections are a major clinical concern due to their high prevalence and the growing risk of antimicrobial resistance. Therefore, it is imperative to develop safe and effective therapeutic strategies.Methods: Herein, we fabricated a novel antibiotic-free nanodrug delivery system (HNK/DG-COS NPs) by loading honokiol (HNK), a hydrophobic natural antimicrobial agent, onto a dual-polysaccharide carrier composed of chitosan (COS) and β-D-glucan (DG), for the treatment of MRSA-infected wounds. COS endows the nanoparticles with synergistic antibacterial activity together with HNK, while DG improves their anti-inflammatory and tissue repair capacities. The physicochemical characteristics of nanoparticles, as well as their in vitro antibacterial and anti-inflammatory activities, were systematically evaluated. Furthermore, an MRSA-infected wound model was constructed to verify their therapeutic efficacy.Results: HNK/DG-COS NPs exhibited a spherical morphology with a uniform particle size of approximately 200 nm. In vitro experiments have shown that HNK/DG-COS NPs can significantly kill MRSA and inhibit biofilm formation. Scanning electron microscopy further revealed that the nanoparticles exerted antibacterial effects by disrupting the integrity of bacterial cell membranes. In LPS-stimulated RAW264.7 macrophages, treatment with HNK/DG-COS NPs significantly mitigated pro-inflammatory cytokine levels. Cell migration assays confirmed that nanoparticles effectively enhanced L929 cell migration. In vivo, treatment with HNK/DG-COS NPs significantly accelerated MRSA-infected wound healing in mice, mitigated inflammatory damage, stimulated collagen production and repaired damaged tissues.Conclusions: HNK/DG-COS NPs represent a promising antibiotic-free candidate for intervention against early-stage MRSA-infected wounds.

In Situ Fabrication of Nerve Growth Factor Encapsulated Chitosan Nanoparticles in Oxidized Bacterial Nanocellulose for Rat Sciatic Nerve Regeneration

Zhao Wei,Feng F. Hong,Zhangjun Cao,Sheng-Yin Zhao,Lin Chen

Autograft is currently the gold standard in the clinical treatment of peripheral nerve injury (PNI), which, however, is limited by the availability of a donor nerve and secondary injuries. Nerve guidance conduits (NGC) provide a suitable microenvironment to promote the regeneration of injured nerves, which could be the substitutes for autografts. In this study, nerve growth factor (NGF) encapsulated chitosan nanoparticles (CSNPs) were first constructed in situ in an oxidized bacterial cellulose (OBC) conduit using the ion gel method after the introduction of a CS/NGF solution under pressure to enable a sustainable release of NGF. A novel NGF@CSNPs/OBC nanocomposite with antibacterial activity, biodegradability, and porous microstructure was successfully developed. In vitro experiments showed that the nanocomposite promoted the adhesion and proliferation of Schwann cells. When the nanocomposite was applied as NGC to repair the sciatic nerve defect of rats, a successful repair of the 10 mm nerve defect was observed after 4 weeks. At week 9, the diameter, morphology, histology, and functional recovery of the regenerated nerve was comparable to the autografts, indicating that the NGC effectively promoted the regeneration and function recovery of the nerve. In summary, the NGF@CSNPs/OBC as a novel NGC provides great potential in the treatment of PNI.

Mandarin (Citrus reticulata L.) essential oil incorporated into chitosan nanoparticles: Characterization, anti-biofilm properties and application in pork preservation

Xueying Song,Lei Wang,Ting Liu,Yongfeng Liu,Xiaoxia Wu,Liu Liu

Mandarin ( Citrus reticulata L.) essential oil (MEO) reportedly displays excellent antimicrobial properties . In this study, MEO was loaded into chitosan nanoparticles (CSNPs). The characteristics, antibacterial properties and benefit in pork preservation of MEO-CSNPs were evaluated. The MEO-CSNPs displayed an excellent encapsulation efficiency (EE) (67.32%–82.35%), the particle size values of 131.3 nm–161.9 nm, and the absolute zeta potential values above 30 mV. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, and thermogravimetric analysis (TGA) revealed that the MEO was incorporated into CSNPs without requiring a chemical reaction, the antibacterial activity of the MEO remained. Furthermore, the damage of MEO-chitosan nanoemulsions (MEO-CSs) to the cell membranes of Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ) was confirmed by the change of bacterial cell morphology. The anti-biofilm assays verified that the MEO-CSs substantially inhibited biofilm formation and destroyed the mature biofilms. MEO-CSs were also applied to pork, proving a great potential for pork preservation. This study provides a potential approach for developing and utilizing MEO-CSs as natural antimicrobial agents in the food industry.

Effects of Chitosan Nanoparticles and 4,4′ Methylene-Diphenyl Diisocyanate on the Polylactic Acid/Poly (Butyleneadipate-Co-Terephthalate) Composite Properties

Jiaqi Wu,Limei Wang,Bin Qi

Polylactic acid (PLA) is considered a mature alternative to synthetic plastics made from petroleum by-products, possessing the advantages of good mechanical strength. However, it also has some disadvantages such as brittleness and low toughness. In order to overcome and improve some of these unfavorable properties, PLA/PBAT composites were prepared by blending PLA with Poly (butylene adipate-co-terephthalate) (PBAT), and adding 4,4′-methylene diphenyl diisocyanate (MDI) and chitosan nanoparticles (ChNPs) as compatibilizers to investigate the effects of different compatibilizers on the properties of the composites. The main observations are as follows: FT-IR indicated that MDI did not add new groups, while the addition of ChNPs added a substantial amount of hydroxyl and methylene groups. The addition of both MDI and ChNPs did not have any effect on the crystalline shape of the composites, but could potentially reduce their crystallinity, increase the melt peak temperature, wet the boundary of the PLA and PBAT phases, decrease the size of the dispersed phases, reduce the number of dispersed phases, and improve interfacial compatibility. The incorporation of MDI increased the tensile strength from 13.02 MPa to 19.24 MPa, whereas the addition of ChNPs substantially enhanced the elongation at the break from 3.84% to 19.24%. Furthermore, the inclusion of MDI conferred enhanced moisture resistance, whereas the addition of ChNPs seemed to weaken the resistance to moisture.Keywords:polylactic acid;poly (butyleneadipate-co-terephthalate);4,4′-methylene-diphenyl diisocyanate;chitosan nanoparticles;interfacial compatibility;compatibilizers;composites

Preparation and characterization of the Adriamycin‑loaded amphiphilic chitosan nanoparticles and their application in the treatment of liver cancer

Chang‑Hua Kou,Jin Han,Xi‑Lin Han,Hui‑Jie Zhuang,Zi‑Ming Zhao

In the present study, two nanoparticles including lactose myristoyl carboxymethyl chitosan (LMCC) and algal polysaccharide myristoyl carboxymethyl chitosan (AMCC), were obtained for hepatic‑targeted Adriamycin (ADM) drug delivery systems. ADM was successfully loaded into the LMCC or AMCC nanoparticle by dialysis. The release function and liver targeting of the nanoparticles was explored, and it was revealed that ADM release from the nanoparticles was greatest at acidic pH 5.5. ADM‑conjugated nanoparticles were readily taken up by HU7 human hepatocellular carcinoma cells, relative to HT22 mouse hippocampal neuron cells in vitro. In vivo, ADM‑loaded nanoparticles had significant antitumor efficacy with a 62.7% inhibition rate, followed by ADM and ADM‑AMCC (51.2 and 42.5%, respectively). The tissue distribution study confirmed that ADM‑LMCC had an improved liver delivery efficacy, by comparison with ADM. Furthermore, a series of safety studies, including hemolysis, acute toxicity and organ toxicity, revealed that the ADM‑loaded LMCC and AMCC nanoparticles had advantages over the commercially available injectable preparation of Adriamycin hydrochloride, in terms of low toxicity levels and increased tolerated dose. These results indicated that LMCC is a promising carrier for injectable ADM nanoparticle and ADM‑conjugated nanoparticles may improve the efficacy of ADM by hepatic targeting.

Octahydrogenated retinoic acid-conjugated glycol chitosan nanoparticles as a novel carrier of azadirachtin: Synthesis, characterization, and in vitro evaluation

Wei Lu,Meng-Ling Lu,Qing-Peng Zhang,Yong-Qing Tian,Zhi-Xiang Zhang,Han-Hong Xu

Environment-friendly and controlled release formulation is highly promising for reducing environmental pollution and achieving the most effective utilization of pesticides. As a novel “green” nanocarrier of pesticides, amphiphilic self-assembled nanoparticles were prepared by chemical conjugation of octahydrogenated retinoic acid (OR) to the backbone of glycol chitosan (GC). In aqueous media, the synthesized OR-GC conjugates formed nanosized particles with a diameter of 257 nm. Hydrophobic azadirachtin (AZA) was efficiently loaded into the OR-GC nanoparticles at a feed weight ratio of up to 1:4 using a simple dialysis method, the maximum drug-loading efficiency of which was 74%. AZA-OR-GC (25 wt %) nanoparticles also showed sustained release of the incorporated AZA (65% of the loaded dose was released in 7 days at 27 °C in phosphate-buffered saline; pH 7.2). Cytotoxicity tests and cell cycle arrest assays confirmed that OR-GC exhibits good biocompatibility; AZA-OR-GC (25 wt %) nanoparticles also showed favorable inhibition of cell proliferation in Sl-1 cells compared with free AZA in organic solvents. Overall, controlled release AZA-OR-GC may be a promising environment-friendly formulation for integrated pest management. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51 , 3932–3940

Sol–gel encapsulation of pullulanase in the presence of hybrid magnetic (Fe3O4–chitosan) nanoparticles improves thermal and operational stability

Long Jie,Li Xingfei,Zhan Xiaobei,Xu Xueming,Tian Yaoqi,Xie Zhengjun,Jin Zhengyu

Abstract Pullulanase was sol–gel encapsulated in the presence of magnetic chitosan/Fe 3 O 4 nanoparticles. The resulting immobilized pullulanase was characterized by scanning electron microscopy, vibrating sample magnetometry, Fourier transform infrared spectroscopy and thermogravimetric analysis. The results showed that the addition of pullulanase created a more regular surface on the sol–gel matrix and an enhanced magnetic response to an applied magnetic field. The maximal activity retention (83.9%) and specific activity (291.7 U/mg) of the immobilized pullulanase were observed under optimized conditions including an octyltriethoxysilane:tetraethoxysilane (OTES:TEOS) ratio of 1:2 and enzyme concentration of 0.484 mg/mL sol. The immobilized enzyme exhibited good thermal stability. When the temperature was above 60 °C, the immobilized pullulanase showed significantly higher activity than the free enzyme ( p  < 0.01); enzyme immobilized by simple sol–gel encapsulation and co-immobilized by crosslinking-encapsulation retained 52 and 69% of their initial activity after 5 h at 62 °C, respectively, compared to 11% for the free enzyme. Moreover, the stability of the pullulanase was improved by crosslinking-encapsulation, as the enzyme retained more than 85 and 81% of its original activity after 5 and 6 consecutive reuses, respectively, compared to 80 and 72% of its original activity for simple sol–gel encapsulated enzymes. This indicated the leakage of enzyme molecules through the pores of the gel was substantially abated by cross-linking. Such immobilized pullulanase provides high stability and ease of enzyme recovery, characteristics that are advantageous for applications in the food industry that involve continuous starch processing. Graphical abstract

Enhancing the Thermo-Stability and Anti-Biofilm Activity of Alginate Lyase by Immobilization on Low Molecular Weight Chitosan Nanoparticles

Shangyong Li,Yanan Wang,Xiao Li,Beom Suk Lee,Samil Jung,Myeong-Sok Lee

Bacterial biofilm causes severe antibiotic resistance. An extracellular polymeric substance (EPS) is the main component in the bacterial biofilm. Alginate is a key EPS component in the biofilm ofPseudomonas aeruginosaand responsible for surface adhesion and stabilization of biofilm. Alginate lyase has emerged as an efficient therapeutic strategy targeting to degrade the alginate in the biofilm ofP. aeruginosa. However, the application of this enzyme is limited by its poor stability. In this study, chitosan nanoparticles (CS-NPs) were synthesized using low molecular weight chitosan and alginate lyase Aly08 was immobilized on low molecular weight chitosan nanoparticles (AL-LMW-CS-NPs). As a result, the immobilization significantly enhanced the thermal stability and reusability of Aly08. In addition, compared with free Aly08, the immobilized AL-LMW-CS-NPs exhibited higher efficiency in inhibiting biofilm formation and interrupting the established mature biofilm ofP. aeruginosa, which could reduce its biomass and thickness confirmed by confocal microscopy. Moreover, the biofilm disruption greatly increased the antibiotic sensitivity ofP. aeruginosa. This research will contribute to the further development of alginate lyase as an anti-biofilm agent.Keywords:immobilization;chitosan nanoparticles;alginate lyase;anti-biofilm activity;antibiotics susceptibility