查找使用阿拉丁产品的科研文献

Function of chitosan in a DOPO-based flame retardant modified epoxy resin

Xinyu Wang,Chenyu Zhou,Shengsong Dai,Junjie Wang,Zhiquan Pan,Hong Zhou

A bio-based flame retardant (PDE) was synthesized through a facile one-pot reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) with protocatechualdehyde and ethanol. PDE was fully characterized by fourier transform infrared spectroscopy (FTIR), 1 H NMR, 31 P NMR and ESI-MS. Epoxy resin (EP) with 9 wt% PDE (EP/9%PDE) passed UL94 V-0 rating and possessed the limited oxygen index (LOI) value of 33.2%, the curved EP thermosets kept transparent. When chitosan (CS) was used to replace one-third of PDE in EP/9% PDE, the modified EP also passed UL94 V-0 rating with the LOI value of 32.3%, the curved thermosets kept transparent and owned better absorption effect toward ultraviolet light. Cone calorimeter test and TG-FTIR analysis were performed on the EP samples, the chars after burning were characterized by scanning electron microscope (SEM), energy-dispersive X-Ray spectroscopy (EDX), Raman spectrum and FTIR. The results showed that the synergistic effect of PDE-CS on flame retardant was ascribed to the protective effect of denser char layer, the release of some phosphorus containing free radicals and the dilution effect of released nonflammable gases such as H 2 O and CO 2 .

Preparation, antioxidant and antibacterial activities of cryptate copper(II)/sulfonate chitosan complexes

Huixiang Wu,Yujun Zhang,Hao Chen,Jing Liu,Lili Xiu,Jianying Huang

In this work, we synthesized cryptate copper(II) followed by complexed with sulfonate chitosan (SCS). After characterization, the evaluation of the antioxidant properties of resulting complexes were carried out by 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH•), hydroxyl radical (•OH), and 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS •+ ), while the antibacterial and biofilm inhibitory activity against Pseudomonas aeruginosa PAO1 ( P. aeruginosa PAO1) were also investigated. According to the results, cryptate copper(II) exhibited the best antioxidant activity followed by cryptate copper(II)/SCS complexes, and SCS. Significant antibacterial activity of cryptate copper(II) against P. aeruginosa PAO1 was observed with the minimum inhibitory concentration of MIC value 12.50 μg/mL and minimum bactericidal concentration of MBC value 100.00 μg/mL, followed by cryptate copper(II)/SCS complexes and SCS. Cryptate copper(II) and cryptate copper(II)/SCS exhibited antibacterial activity which copper ions might enter the interior of cells, and the intracellular ions made the killed bacteria serve as an antibacterial agent showing a zombie effect. The copper ions complexed with cryptate and SCS rendering potential unlimited biological activities, might become one of the most popular research areas because of their unique coordination chemistry and their long-term biological activities.

Fabrication, characterization, and in vitro evaluation of doxorubicin-coupled chitosan oligosaccharide nanoparticles

Guo Yi,Junhong Ling,Yongjun Jiang,YuQing Lu,Li-Ye Yang,Xiao–kun Ouyang

In this study, we developed pH-sensitive chito-oligosaccharide nano-drug-loaded particles with good biocompatibility, biodegradation, and controlled drug delivery. Chitosan oligosaccharides (COS), Doxorubicin (DOX) amino groups, and aromatic aldehydes of benzaldehyde-terminated polyethylene glycol were used to spontaneously form pH-sensitive aniline bonds. We aimed to achieve site targeting under weak acidic tumor conditions, improve the efficacy, and reduce the toxic side effects of the drug. Particle size, drug encapsulation efficiency, loading efficiency, and zeta potential of nanoparticles were optimized by altering the ratios of aldehyde, amino groups, and sodium tripolyphosphate. The drug encapsulation efficiency and loading efficiency of COS-DOX1 were 5.55 ± 0.13% and 88.81 ± 2.00%, respectively, and the in vitro drug release process displayed a specific pH responsiveness. Co-culture of COS-DOX with HCT-116 human colon cancer cells showed that the nanoparticles exhibited dose-dependent cytotoxicity. At a low dose, COS-DOX1 can promote DOX uptake of tumor cells and exhibit higher cytotoxicity than DOX alone.

Formulation of Food-Grade Grease Using Paraffin Oil, Fumed Silica, and Chitosan

Mohd Khairul Nizam,Mohamad Shafiq Mohd Razmi,Najmuddin Mohd Ramli,Mohd Najib Razali

Three formulations intended for NSF H1 food-grade grease were prepared in this study comprising paraffin oil as a base oil and fumed silica as a thickener. No additive was added in formulation 1 (F1) and formulation 2 (F2), whereas chitosan was added in formulation 3 (F3) as an additive. A commercial food-grade grease (FGG) was used for comparison purposes. The formulated greases and the commercial FGG were characterised for thermal stability via thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG). Fourier-transform infrared (FTIR) spectroscopy, dropping point, oil separation, and consistency tests were also carried out to evaluate the properties of the greases. The FTIR spectra were obtained for the fresh and aged greases for grease characterisation. The results showed that the grease made with chitosan as an additive demonstrated higher oil separation, better consistency, and was less affected by ageing, as indicated by the change of grease colour after the oil separation test. F1, F2, F3, and the commercial FGG recorded dropping points higher than 350 °C, indicating no dropping point properties for the tested greases. The grease formulated with chitosan (F3) achieved the highest oil separation with 1.21%, while the commercial FGG recorded the lowest oil separation with 0.66%, followed by F1 and F3 with the oil separation of 0.99% and 0.98%, respectively. For the consistency test, the NLGI number for each formulation varied but the commercial FGG showed the lowest NLGI number of 2, whereas F3 showed the NLGI number in the range of 2–3, and F1 showed the NLGI number of 3. The aged grease of F3 had unchanged consistency after the oil separation test. Based on the results, the formulated greases have acceptable properties in comparison to the commercial FGG, and the addition of chitosan contributes positively to the grease characteristics.

In vivo antitumor effects of carboxymethyl chitosan-conjugated triptolide after oral administration

Huahui Zeng,Xin Zhu,Qikang Tian,Yinyin Yan,Lan Zhang,Min Yan,Ruiqin Li,Xiaofang Li,Guoqiang Wang,Jinlian Ma,Yufang Su,Xiangbo Zhang,Linyu Ma,Zhenqiang Zhang,Xiangxiang Wu

Synthesis of modified chitosan-based molecularly imprinted polymers for adsorptive protein separation

Shan Yang,Yuzhi Wang,Minli Xu,Meizhi He,Min Zhang,Dan Ran,Xiaopin Jia

A simple molecularly imprinted polymer (MIP) was prepared to recognize the template lysozyme (Lys). Chitosan (CS) was selected as the functional biopolymer to enhance the adsorption capacity. The aldehyde group was introduced to CS, so that the template protein could be immobilized onto the modified CS beads. After the template protein was successfully immobilized, two kinds of organic siloxane, tetraethoxysiloxane (TEOS) and 3-aminopropyl triethoxysilane (APTES), were added and polymerized via a sol–gel process in aqueous solution at 25 °C. After template removal, adsorption experiments were performed to study the properties of the synthesized MIP. The results showed that the MIP exhibited much higher adsorption capacity for Lys than the non-imprinted polymer (NIP). The theoretical maximum adsorption capacity (Qmax) and equilibrium constant (KL) were determined by the Langmuir model, which turned out to be 15.89 mg g−1 and 6.78. The selectivity of the MIP was verified by direct adsorption of a single reference protein and mixed protein. The UV measurement and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis results showed the MIP had a relatively high adsorption capacity and excellent selectivity, which made it possible to remove the template protein from different sample solutions.

Chitosan-based asymmetric topological membranes with cell-like features for healthcare applications

Yulin Jiang,Yi Deng,Ying Tu,Birol Ay,Xiaodong Sun,Yubao Li,Xiaohong Wang,Xianchun Chen,Li Zhang

Chitosan-based guided tissue regeneration (GTR) membranes are extensively used in orthopedic/stomatological regenerative medicine since chitosan shares many chemical and structural similarities with glycosaminoglycans (GAGs) in the extracellular matrix. However, the available chitosan-based GTR membranes mostly lack topological features of natural tissues, resulting in unsatisfactory biocompatibility. To address this limitation, we developed a novel biologically-inspired asymmetric topological chitosan (ATCS) membrane supported by a nanoporous anodic aluminum oxide (AAO) template. We, thereafter, investigated the mechanical properties, degradation, and cytocompatibility of the ATCS membranes and compared them with those of the symmetric chitosan (SyCS) membranes, produced with a smooth Al template. The asymmetric topological structure significantly increased the tensile strength but decreased the extent of degradation of the ATCS membranes compared to those of SyCS. In the in vitro studies, the ATCS membranes outperformed the SyCS membranes in cytocompatibility due to their cell-like features. In addition to the ATCS membranes, the ethylene vinyl acetate (EVA) membranes with a similar cell-like structure were successfully fabricated using the AAO template to verify the universality of the AAO template-assisted technique. Accordingly, the AAO template-assisted strategy, defined in this study, is an innovative, universal, and facile way to fabricate polymeric asymmetric membranes with cell-like features. The bioengineered ATCS membranes with tunable degradability, prominent mechanical properties and biocompatibility are promising candidates for orthopedic healthcare applications.

Novel Carboxylated Chitosan-Based Triptolide Conjugate for the Treatment of Rheumatoid Arthritis

Lan Zhang,Min Yan,Kun Chen,Qikang Tian,Junying Song,Zijuan Zhang,Zhishen Xie,Yong Yuan,Yaquan Jia,Xin Zhu,Zhenqiang Zhang,Xiangxiang Wu,Huahui Zeng

A new platform for triptolide (TP) delivery was prepared by conjugating TP to a carboxylmethyl chitosan (CMCS). Compared with the natural TP, the TP-conjugate (TP-CMCS) containing TP of ~5 wt% exhibited excellent aqueous solubility (>5 mg/mL). Results of in vitro experiments showed that TP-CMCS could relieve TP-induced inhibition on RAW264.7 cells and apoptosis, respectively. Compared with the TP group, TP-CMCS could effectively alleviate the toxicity injury of TP and decreased the mortality rate of the mice (p< 0.05). TP-CMCS did not cause much damage to the liver (AST and ALT) and kidney (BUN and CRE) (p< 0.05). After administration, the levels of IL-6, IL-1β, and TNF-α decreased, and the arthritis detumescence percentages increased significantly, and the bony erosion degree was distinctly decreased in the TP-CMCS groups and TP group. Our results suggested that TP-CMCS was a useful carrier for the treatment of RA, which enhanced aqueous solubility of free TP and reduced drug toxicity in vitro and in vivo.Keywords:triptolide;toxicity;water solubility;carboxylmethyl chitosan;drug carrier system

Berberine Hydrochloride-Loaded Chitosan Nanoparticles Effectively Targets and Suppresses Human Nasopharyngeal Carcinoma

Wang Yonghong,Wen Baofang,Yu Hongli,Ding Dejun,Zhang JingJing,Zhang Yunxiang,Zhao Limin,Zhang Weifen

Nasopharyngeal carcinoma (NPC) is a common epithelial malignancy that occurs in the nasopharynx and it is one of the high incidences of malignant tumors in China. As previous reports, berberine hydrochloride (BH) possesses a repressive effect on the proliferation of various cancer types. But the application of BH was hampered for a long time due to its hydrophobic properties, along with poor stability and bioavailability. In this study, folate acid modified chitosan nanoparticles loaded berberine hydrochloride (BH/FA-CTS NPs) were prepared by the ionic cross-linking technique, the physicochemical properties and the influence of BH/FA-CTS NPs on proliferation, migration and apoptosis in human nasopharyngeal carcinoma CNE-1 cells were studied in vitro and in vivo. Results of scanning electron microscopy (SEM) images showed that BH/FA-CTS NPs were sphere and the diameter was 258.2±9.1 nm. The drug loading and encapsulation efficiency were 8.17±1.12% and 87.73±4.21%, respectively. The drug release kinetics exhibited a slower and sustained release over a period of 48 h. Moreover, results of MTT assay and scratch assay displayed that BH/FA-CTS NPs inhibited proliferation and migration of CNE-1 cells remarkably. BH/FA-CTS NPs promoted apoptosis and necrosis of CNE-1 cells. And BH/FA-CTS NPs displayed distinguished higher tumor inhibition than control group, free BH and BH/CTS NPs in vivo. Therefore, as a nanocomposite, BH/FA-CTS NPs provide a new method and option for the treatment of nasopharyngeal carcinoma patients.

Improved membrane stability of alginate-chitosan microcapsules by crosslinking with tannic acid

Chen Li,Jiang Fang,Xu Haidan,Fan Yaoyao,Du Cunbin

Objective The insufficient stability of alginate-chitosan (ALG-CS) microcapsules in biorelevant media limits their applications in the biomedical field. Attempts were made to improve the membrane stability of ALG-CS microcapsules by noncovalent crosslinking with tannic acid. Results The membrane stability of ALG-CS microcapsules in culture medium and serum was significantly improved by crosslinking with tannic acid. Moreover, the reason for the significant improvement in membrane stability had been demonstrated to be that the stability of chitosan-tannic acid (CS-TA) polyelectrolyte complexes was less affected by the competitive binding of those weak acid ions such as HCO 3 − . In addition, the optimal conditions for preparing alginate-chitosan-tannic acid (ALG-CS-TA) microcapsules were tannic acid concentration of 0.5% (w/v) and pH = 7. Conclusion The study provides a novel approach for improving the stability of the ALG-CS microcapsules in biorelevant media to expand their scope of application in the biological field.

Fabrication of graphene oxide-modified chitosan for controlled release of dexamethasone phosphate

Sun Huanghui,Zhang Lingfan,Xia Wei,Chen Linxiao,Xu Zhizhen,Zhang Wenqing

Functionalized graphene oxide with its unique physical and chemical properties is widely applied in biomaterials, especially in drug carrier materials. In the past few years, a number of different drugs have been loaded on functionalized graphene oxide via π–π stacking and hydrophobic interactions. The present report described a new approach, dexamethasone phosphate successfully loaded onto graphene oxide–chitosan nanocomposites as drug carrier materials by covalent bonding of phosphate ester linkage. Compared with the graphene oxide–chitosan nanocomposites that dexamethasone phosphate was loaded on via simple physical attachment, covalently linked composites as drug carrier materials were more biocompatible which effectively reduced the burst release of drug, and controlled the release of drug in different pH conditions.

Chitosan oligosaccharide derived polar host for lithium deposition in lithium metal batteries

Zeheng Li,Nan Xu,Ying Sha,Jiapeng Ji,Tiefeng Liu,Lijing Yan,Yi He,Junchao Zheng,Min Ling,Yingying Lu,Chengdu Liang

Rechargeable lithium metal batteries are among the most versatile platforms for high energy electrochemical energy storage . Unfortunately, uncontrollable growth of lithium dendrite triggers serious safety hazards, low Coulombic efficiency, and short cycling life, impeding the commercial application of lithium metal anode in the advanced energy storage technology , such as lithium-air and lithium‑sulfur (Li S) batteries. Herein, Chitosan oligosaccharide (CSO), an abundant bioderived material was employed to guide uniform lithium deposition and growth. CSO offers three features simultaneously, polar functional groups (-OH and -NH 2 ), natural porous structure , and abundant sources. CSO with a large number of polar groups has strong interactions with Li ions , which could guide the Li ions to form uniform Li deposition. Moreover, the porous structure of CSO could serve as a Li host to accommodate the huge volume change during Li plating and stripping process. Additionally, CSO is a low-cost, abundant, and nontoxic bioderived material, which is suitable for large-scale production of the CSO-Li anode. The proposed strong interactions of CSO with Li ions were confirmed by density functional theory calculations. As expected, the CSO modified electrode demonstrates an outstanding average Coulombic efficiency of over 98% for 600 cycles at a current density of 2 mA cm −2 . And stable cycling performances were achieved in the CSO-Li/CSO-Li symmetrical cells. Moreover, when paired with the LiFePO 4 cathode, Li 4 Ti 5 O 12 anode, high-mass-loading LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode, and S cathode, the cells using the CSO-Li anodes show the higher capacities and better cycling stabilities compared with those of the cells using the bare Li anodes.