查找使用阿拉丁产品的科研文献

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.

Removal of Sr(II) from water with highly-elastic carboxymethyl chitosan gel

Jinfeng Mei,Siqi Mo,Hui Zhang,Xudong Zheng,Zhongyu Li

A carboxymethyl chitosan (O-CMC) gel was prepared by crosslinking and functionalizing with ethylenediaminetetraacetic acid (EDTA) using a one-pot reaction under mild conditions. Structural characterizations have revealed that the prepared O-CMC/EDTA gel has 3D porous structure with abundant carboxyl groups distributed in the pores. The prepared O-CMC/EDTA gel was used to adsorb Sr(II) ions in water while X-ray photoelectron spectroscopy (XPS) was used to explore the adsorption mechanism. In order to analyze the adsorption process, we performed the adsorption kinetics and isotherms. The results show that the maximum adsorption capacity of O-CMC/EDTA for Sr (II) ions is about 105.81 mg/g at pH = 7. Notably, it exhibited fairly high compression elasticity due to multiple hydrogen bonds in the network. The showed no deformation after 30 continuous compression cycles. The ratio of O-CMC:EDTA significantly influences the adsorption property by affecting the crosslinking degree as well as the number of active sites. The high adsorption capacity, elasticity, and reusability have demonstrated that the prepared material is an effective and promising adsorbent for Sr(II) removal.

Fabrication of carboxymethyl chitosan-strontium chondroitin sulfate composites for potential bone regeneration

Meixin Li,Lei Xu,Fenbo Ma,Bin Tang,Chenghe Qin

Large bone defects have been a major healthcare concern. These defects are difficult to heal because of the chronic inflammatory environment surrounding the injury area. Osteoconductive composites with anti-inflammatory effects could provide a substrate to support cell growth and guide bone defect repair. Here, we synthesized a biofunctional composite that combined carboxymethyl-chitosan (CMCS) and strontium chondroitin sulfate (SrCS), for potential use in bone regeneration. We hypothesized that the as-prepared CMCS-SrCS composites could stimulate osteogenic activity and suppress inflammatory responses. The resultant composites displayed uniformly porous structures and good swelling capacity. The effect of the composites on MC3T3-E1 cells was investigated in vitro and the live cells showed favorable viability. Moreover, the RT-PCR results indicated that the CMCS-SrCS composites could suppress inflammatory responses and promote the osteogenic differentiation of MC3T3-E1 cells. These results suggested the CMCS-SrCS composites should have osteoconductive characteristics. Thus, we believe that the developed CMCS-SrCS composites should be a promising skeletal candidate for regenerative engineering applications.

Eudragit® L100-coated mannosylated chitosan nanoparticles for oral protein vaccine delivery

Bohui Xu,Wenjing Zhang,Yulin Chen,Yan Xu,Bo Wang,Li Zong

The aim of this study was to develop a novel biodegradable polymeric carrier for the delivery of protein vaccine orally in order to target the antigen presenting cells (APCs) in the region of Peyer's patches (PPs). Here, bovine serum albumin (BSA) was chosen as a model protein vaccine and was loaded into the mannosylated chitosan nanoparticles (MCS NPs) by ionic gelation method with tripolyphosphate (TPP), followed by coating MCS NPs with Eudragit® L100 (Eud) by electrostatic interaction. The spherical NPs were successfully prepared with appropriate particle size around 558.2   ±   35.6   nm, high entrapment efficiency about 90.38   ±   9.12%, good stability and reasonable release behavior in the simulated gastrointestinal fluid, meanwhile high resistance of enzymatic and acid degradations were verified. The targeting ability of the NPs to PPs in rat was investigated by a closed ileal loop assay, where fluorescence visualization was performed. MCS NPs were accumulated more specifically into PPs after Eudragit® L100 dissolved in intestinal juices. Oral immunization using BSA-loaded Eudragit® L100-coated MCS NPs was found to elicit strong systemic IgG antibody and mucosal IgA responses. These results suggested that enteric-coated MCS NPs could serve as a promising carrier for oral protein vaccine delivery.

Simple fabrication of inner chitosan-coated alginate hollow microfiber with higher stability

Hui Liu,Yaqing Wang,Yue Yu,Wenwen Chen,Lei Jiang,Jianhua Qin

Sodium alginate (NaA) has been widely used as microfiber-based scaffold material. However, Ca-alginate microfiber might disintegrate in the physiological environment due to the loss of calcium ions, which will limit its long-term application in tissue engineering. In this work, to enhance the stability of Ca-alginate microfiber in the physiological environment, an inner chitosan coating was introduced to Ca-alginate hollow microfiber by one step via a microfluidic device. A more stable composite microfiber with double cross-linking layers was generated. The stability of the microfiber was studied in the PBS solution (pH 7.4) to identify the coating effect on the hollow structure. The results revealed that chitosan component bonded an NaA layer to form a stable polyelectrolyte complex membrane in the inner wall of the microfiber, which stabilized the hollow region even though the Ca-alginate shell was disintegrated by PBS solution. In addition, the introduction of chitosan coating improved the inner environment of the low affinity of alginate to cell surfaces and facilitated the cell adhesion and culture in the microfiber. HepG2 cells in the microfibers displayed favorable cell viability and proliferation ability. We believe that this work will lead to the development of innovative methodologies and materials for both cell culture and tissue engineering application. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2527–2536, 2019.

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.

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

A chitosan/dopamine-TiO2 composite nanofiltration membrane for antifouling in water purification

Wang Dong,Lin Junkang,Huang Jianhua,Zhang Hui,Lin Shan,Chen Lihui,Ni Yonghao,Huang Liulian

A major obstacle for the development of the cellulose-based nanofiltration membrane is its fouling. In this study, a novel cellulose-based composite nanofiltration membrane (CS/DA-TiO 2 -NFM) with excellent anti-fouling performance was prepared through casting of both chitosan (CS) and TiO 2 modified by dopamine (DA-TiO 2 ) on the cellulose substrate membrane. DA-TiO 2 was successfully introduced into the surface of membrane, resulting in significant improvement in its hydrophilicity due to the formation of dense CS layers. Furthermore, both CS and DA-TiO 2 were effective antimicrobial agents (against E. coli 90.6% and S. aureus 95.1%) that could minimize the accumulation of bacteria on the CS/DA-TiO 2 -NFM. For the antifouling test against BSA, the irreversible recovery ratio of the CS/DA-TiO 2 -NFM was only 23.25% of the control (no CS/DA-TiO 2 modified NFM). In addition, the CS/DA-TiO 2 -NFM exhibited an increased rejection rate of MgSO 4 (enhanced 40.93%) and water-flux (enhanced 18.10%) compared with the control. These results highlight the potential of the presented approach for designing membranes with effective separation performance and antifouling for drinking water treatment. Graphic abstract

Self-assemblied nanocomplexes based on biomimetic amphiphilic chitosan derivatives for protein delivery

Minming Wu,Hongwei Dong,Kai Guo,Rong Zeng,Mei Tu,Jianhao Zhao

A bio-inspired nanocarrier was developed for protein delivery based on biodegradable amphiphilic chitosan derivative (DCA–PCCs) with hydrophilic cell membrane mimic phosphorylcholine (PC) and hydrophobic deoxycholic acid (DCA) moieties, which was synthesized via the combination of Atherton–Todd reaction and carbodiimide coupling reaction. Using bovine serum albumin (BSA) as model protein, it was found that DCA–PCCs with suitable degree of substitution of PC and DCA moieties can load proteins by forming nanocomplexes via a solvent evaporation method. The physicochemical characteristics of BSA/DCA–PCCs nanocomplexes were investigated by Zetasizer, atomic force microscopy (AFM) and Fourier-transform infrared (FT-IR) spectroscopy. In vitro biological evaluation revealed BSA/DCA–PCCs nanocomplexes as blank DCA–PCCs nanoparticles had excellent cytocompatibility and hemocompatibility mainly due to the presence of cell membrane mimic phosphorylcholine. BSA release results suggested BSA/DCA–PCCs nanocomplexes showed a sustained release behavior following first order exponential decay kinetics. The results indicated DCA–PCCs provided a promising approach for effectively delivering therapeutic proteins.

Assembling Alkaline-Responsive Chitosan@Giant Liposomes through an Ultrasound-Integrated Microfluidic Approach

Mengting Lv,Huanan Li,Hua Cao,Teng Wang,Chengdian He,Yi Liang,Xiang Mao,Zhenyu Wang

This paper presents the fabrication of an alkaline-responsive drug carrier, chitosan@giant liposome (CS-GL), by using an ultrasound-integrated microfluidic approach. On the microfluidic chip, water/oil/water droplets are first prepared and then move through an area of ultrasonic radiation to improve the regional saturation of organic solvent and accelerate its removal. At the same time, phospholipid molecules in the oil phase of the droplets are efficiently self-assembled into giant liposomes (GLs). Subsequently, microfluidic channels combined with an up–down separated structure can help in the fabrication and purification of the GLs. Due to the electrostatic interaction between the amino group of chitosan and the phosphate group of phospholipids, the GLs and chitosan are assembled into CS-GLs. The change of ζ potential after this operation indicates that chitosan is coated on the surface of GLs. The formed CS-GLs are monodispersed with a 54.1 ± 0.7 μm diameter and high drug encapsulation efficiency (∼96%), and the structural integrity can be kept without leakage of contents for more than a week in an acid medium (pH = 1.2). When this structure is placed in an aqueous solution of pH = 7.8, chitosan precipitates gradually and detaches from the GL, causing its rupture. The drug encapsulated in a single CS-GL can be rapidly released within 4 s, and 99.6% of the CS-GL carriers can complete the release within 10 min.

Biomimetic gelatin/chitosan/polyvinyl alcohol/nano-hydroxyapatite scaffolds for bone tissue engineering

Pengfei Ma,Wenjing Wu,Yu Wei,Le Ren,Shuxian Lin,Junhua Wu

Multi-component bone tissue engineering scaffolds are the dominant trend to address complex requirements of bone defect repair. In this study, to mimic component and microstructure of natural bone, polymers (natural and synthetic) and nano-hydroxyapatite (nHAp) were fabricated to form a porous composite scaffold. Gelatin (Gel), chitosan (CS) and polyvinyl alcohol (PVA) were first assembled to simulate extracellular matrix. The simulated matrix exhibited tunable pore size, porosity, swelling, pH, degradation and mechanical strength. After the incorporation of nHAp, the composite scaffolds showed improved compression resistance, pH adaptability, improved surface bioactivity and biomimetic structure. In addition, the composite scaffolds can effectively promote cell proliferation and adhesion, of which, scaffolds containing 12.5% of nHAp were demonstrated to have high osteogenic differentiation ability. Hence, these results suggest that Gel/CS/PVA/nHAp composite scaffolds could be a promising biomimetic scaffold for bone tissue engineering.

A QCM humidity sensor constructed by graphene quantum dots and chitosan composites

Pengjia Qi,Tong Zhang,Jieren Shao,Bai Yang,Teng Fei,Rui Wang

A quartz crystal microbalance (QCM) humidity sensor based on graphene quantum dots-chitosan (GQDs-CS) sensitive film has been successfully fabricated in this work. The composite ratio of sensitive material and the coating quality of the sensitive film were optimized. The morphological and chemical properties of GQDs-CS composites were inspected via scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier Transform infrared spectroscopy (FT-IR). The results manifest that prepared QCM sensor exhibits high response sensitivity (a frequency shift of −3291 Hz at 95% RH), short response/recovery time (36 s/3 s), tiny humidity hysteresis (˜1.6% RH), and excellent reproducibility, reversibility and long-term stability. Additionally, the electroacoustic parameters of the QCM sensors were also investigated by means of the impedance analysis method. Based on dynamic and static analysis of the sensor, it is speculated that the introduction of GQDs into CS enhanced the mechanical stiffness of the CS film, which could effectively improve the performance of QCM sensor.