查找使用阿拉丁产品的科研文献

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.

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.

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.

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.

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

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.

Superhydrophobic MXene@carboxylated carbon nanotubes/carboxymethyl chitosan aerogel for piezoresistive pressure sensor

Zhipeng Yang,Hongqiang Li,Shifeng Zhang,Xuejun Lai,Xingrong Zeng

Flexible and wearable pressure sensors have attracted considerable attention for the wide application prospect in robot sensing, intelligent electronic skin and healthcare monitoring. Herein, a superhydrophobic MXene-coated carboxylated carbon nanotubes (C-CNTs)/carboxymethyl chitosan (CCS) aerogel with honeycomb-like porous microstructure was proposed for piezoresistive pressure sensor. Firstly, a C-CNTs/CCS aerogel with superior robustness, resilience and durability was fabricated via directional freeze-drying method. Secondly, the C-CNTs/CCS aerogel was dip-coated with a layer of MXene nanosheets and then chemically modified with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS). The obtained F-MXene@C-CNTs/CCS aerogel demonstrated superhydrophobicity and the water contact angle and artificial sweat contact angle reached 157° and 154°, respectively. Thanks to the synergism of the dual-conductive MXene-CNTs network, the aerogel-based pressure sensor realized fast response time (62 ms), wide detection range (up to 80 kPa) as well as excellent electrical stability and repeatability even under humid and sweaty environments. Additionally, the sensor was successfully applied for monitoring human motions including not only large-scale actions (joint movements, walking and running) but also small-scale muscle movements (pronunciation recognition and finger tapping). Interestingly, the sensor connected to an Arduino microcontroller circuit with Bluetooth module was able to wirelessly detect real-time movements of finger joints. Our findings conceivably stand out as a new strategy to fabricate high-performance piezoresistive pressure sensors for wide applications even at special working conditions.

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.

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.