查找使用阿拉丁产品的科研文献

Preparation and characterization of oxidized konjac glucomannan/carboxymethyl chitosan/graphene oxide hydrogel

Lihong Fan,Jiayan Yi,Jun Tong,Xiaoyu Zhou,Hongyu Ge,Shengqiong Zou,Huigao Wen,Min Nie

Polysaccharide hydrogels have been widely used as biomaterials in biomedical field. In this article, composite hydrogels were prepared through the Schiff-base reaction between the aldehyde of oxidized konjac glucomannan (OKGM) and the amino of carboxymethyl chitosan (CMCS). Meanwhile, different amount of graphene oxide (GO) was added as nano-additive. The hydrogels have been characterized by various methods including Fourier transform infrared spectroscopy (FT-IR) and Surface morphology (SEM). Through the observation of SEM, the hydrogels’ scaffolds present a homogeneous interconnected pore structure after lyophilizing. In addition, the influence of different GO content on properties including gelation time, swelling ability, water evaporation rate and mechanical properties was investigated. The results indicate that the hydrogels have short gelation time, appropriate swelling ability and water evaporation rate. Especially, the compressive strength and modulus increase 144% and 296% respectively as the GO content increase from 0 to 5   mg/ml. Moreover, MTT assay was applied to evaluate the biocompatibility of hydrogels. The result indicate that hydrogels with GO show better biocompatibility. Therefore, due to the appropriate water absorption capacity, the similar compressive modulus with soft tissue and excellent biocompatibility, the composite hydrogels have potential application in wound dressings.

Synthesis, characterization and anticancer activity of tanshinone I grafted low molecular chitosan

Wang Dongdong,DanXu,Sun Yuelin,Wu Yuanyuan,Ma Lili,Duan Jinyou

In this study, we synthesized a novel water-soluble low molecular chitosan (LMC) derivative through Vilsmeier reaction and reductive amination reaction. The derivative was characterized by UV-visible spectroscopy, 1 H NMR, FTIR and SEM techniques. The results showed that the derivative effectively reduced the cell viability rate, inhibited cell metastasis, induced cell apoptosis and dissipated mitochondrial membrane potential (ΔΨm). Moreover, the antitumor activity was strengthened with the increase of the degree of substitution of tanshinone I (TanI). These findings provided important support for developing new water-soluble antitumor agent and expand the scope of application of LMC.

Chitosan-based magnetic/fluorescent nanocomposites for cell labelling and controlled drug release

Yongling Ding,Hong Yin,Shirley Shen,Kangning Sun,Futian Liu

A chitosan-based drug delivery system, composed of Fe3O4 magnetic nanoparticles (MNPs), CdTe@ZnS quantum dots (QDs) and the anti-cancer drug doxorubicin (DOX), was designed and fabricated. The surfaces of MNPs were modified with carboxymethyl chitosan (CMCS) to minimise the possible fluorescence quenching triggered by magnetic cores. Glutaraldehyde was used as a crosslinking agent to create chemical covalent conjunction between different components, thus enhancing the stability of the obtained nanocomposites. The resulting nanocomposites retain favourable magnetic and fluorescence properties and can be used for bimodal cellular imaging. A sustained pH dependent DOX release with more release at pH = 5.3 was observed. The nanocomposites exhibited low cytotoxicity and CLSM images confirmed the cell fluorescence labelling properties and time-dependent cellular uptake. In summary, the chitosan-based nanocomposites developed in this work provided highly integrated functionalities and are promising for controlled drug delivery and also suitable for in situ cellular imaging.

Biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers for rapid hemostasis

Tingsheng Yan,Feng Cheng,Xinjing Wei,Yudong Huang,Jinmei He

Efficient and biodegradable hemostatic materials become increasingly important in civilian and military clinical. However, traditional hemostatic materials are difficult to achieve expected effects especially in parenchymal organs with rich vascularity. In facing these challenges, we designed a biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers (CPNFs-Col sponge) for rapid hemostasis. With specific performances, such as rapid water absorption ability, the positive surface rich in amino groups and high specific surface area (952.5   m 2   g −1 ), the obtained CNPFs-Col sponge with optimized composition could activate the intrinsic pathway of coagulation cascade, induce haemocytes and platelets adherence, promote the blood clotting and achieve hemorrhage control in vitro and in vivo. In addition, the CNPFs-Col sponge can be completely biodegraded in 3 weeks, which is suitable for post-operative treatment and peritoneal adhesion prevention. It can be concluded that the CPNFs-Col sponge would become a promising candidate for clinical hemostatic applications.

Construction of silver sulfadiazine loaded chitosan composite sponges as potential wound dressings

Wei Shao,Jimin Wu,Shuxia Wang,Min Huang,Xiufeng Liu,Rui Zhang

Chitosan/silver sulfadiazine (CS/AgSD) composite sponges were prepared by incorporating AgSD particles into CS matrix in order to develop novel biomaterials for wound healing. The co-existence of CS and AgSD in the composite sponges was confirmed by SEM, FTIR and XRD spectra, respectively. The porosity and swelling properties of the fabricated CS/AgSD composite sponges were examined and the results indicated that they had high porosity and excellent swelling behaviors. Antibacterial property of the CS/AgSD composite sponges was also performed against E. coli , C. albicans , S. aureus and B. subtilis , respectively. The results showed that they possessed broad spectrum of antibacterial activity. The cytotoxicity of the prepared composite sponges was performed by MTT viability assay and fluorescence staining method on HEK293 cell lines. The cell viability results indicated that the designed sponges had no significant cytotoxicity. The results of this study demonstrated that the CS/AgSD composite sponges have potential application in antimicrobial wound dressing materials.

Preparation and copper ions adsorption properties of thiosemicarbazide chitosan from squid pens

Yue-cheng Lin,Hong-peng Wang,Faryal Gohar,Muhammad Haseeb Ullah,Xiang Zhang,Dong-fang Xie,Hui Fang,Jun Huang,Jun-xing Yang

Chitosan was prepared by alkaline N-deacetylation of β-chitin from squid pens. Thiosemicarbazide group was introduced to chitosan via formaldehyde-derived linkages, and thiosemicarbazide chitosan (TSFCS) with different degrees of substitution (DS) was synthesized. The DS values of TSFCS calculated by elemental analysis were 0.19, 0.36 and 0.63. The structure of the TSFCS was confirmed by elemental analysis, FTIR, XRD, TGA and SEM. The adsorption capacity of Cu(II) ions by TSFCS showed good correlation with the DS and pH (pH range 2.2–5.8). The maximum Cu(II) ions adsorption capacity of all three TSFCS samples reached 134.0   mg   g −1 at pH 3.6, but chitosan showed no adsorption at this pH. The adsorption equilibrium process of Cu(II) ions onto TSFCS was better described by the Langmuir model than the Freundlich isotherm model. Cu(II) ions adsorbed by TSFCS could be released using 0.01   M Na 2 EDTA and the adsorption capacity could retain above 80% after five adsorption-desorption cycles. TSFCS exhibited good potential for heavy metal removal because of its high adsorption capacity at the low pH.

Characterization and adsorption performance of chitosan/diatomite membranes for Orange G removal

Xiu-Juan Wu,Ji-De Wang,Li-Qin Cao

Novel chitosan/diatomite (CS/DM) membranes were prepared by phase inversion technique to remove anionic azo dyes from wastewater. The fabricated composite membranes exhibited the combined advantages of inorganic substances, diatomites, and polysaccharides. These composite membranes were characterized through Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction analysis. The mechanical properties of the membranes were also evaluated. Adsorption experiments were conducted under varied initial dye concentration, solution pH values, contact time, and adsorbent dosage. The results indicate that pH 3 is the optimal pH value for Orange G adsorption. The CS/DM membranes exhibit the highest adsorption capacity of 588 mg g -1 and removal rate of 94% under an initial dye concentration of 200 mg l -1 , contact time of 6 h, and membrane dosage of 8 mg. Langmuir, Freundlich and Redlich-Peterson adsorption models were applied to describe the equilibrium isotherms at different dye concentrations. The equilibrium data was found to be fitted well to the Redlich-Peterson isotherm. Pseudo-first-order and pseudo-second-order kinetics models were used to describe the adsorption of membranes. The adsorption data were well explained by pseudo-second-order models, and also followed by the Elovich model. In addition, these membranes display high adsorption capacity and mechanical performance even after reused for seven times.

Gold nanoparticles make chitosan–streptomycin conjugates effective towards Gram-negative bacterial biofilm

Haibo Mu,Qianjin Liu,Hong Niu,Yuelin Sun,Jinyou Duan

The emergence of biofilm-associated resistance of microbes to traditional antibiotics has resulted in an urgent need for novel antimicrobial agents. Herein we developed a facile approach to overcome the problem through chitosan–streptomycin gold nanoparticles (CA NPs). The synthesized CA NPs were characterized by ultraviolet-visible absorption spectra (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The resulting CA NPs maintained their antibiofilm activities towards Gram-positive organisms. More importantly, CA NPs damaged established biofilms and inhibited biofilm formation of Gram-negative bacteria pathogens. Mechanistic insight demonstrated that CA NPs rendered streptomycin more accessible to biofilms, thereby it was available to interact with biofilm bacteria. Additionally, CA NPs were observed to kill more biofilm-dispersed cells than CS conjugate or streptomycin and inhibit the planktonic cell growth of Gram-positive and -negative bacteria. Thus, this work represents an innovative strategy whereby gold nanoparticles linked to carbohydrate–antibiotic conjugates can overcome antibiotic resistance of microbial biofilms, suggesting the potential of using the generated CA NPs as antimicrobial agents for bacterial infectious diseases.

O-Carboxymethyl Chitosan Supported Heterogeneous Palladium and Ni Catalysts for Heck Reaction

Dongjun Lv,Mingjie Zhang

Two polymer catalysts (Pd-OCMCS and Ni-OCMCS) with good reusability were synthesized by coordinating Pd and Ni ontoO-carboxymethyl chitosan (OCMCS). The chemical structure and thermal stability of prepared catalysts were determined by Fourier transform infrared (FT-IR) spectra, Energy Dispersive Spectrometer (EDS)analysis, X-ray diffraction (XRD), and thermogravimetric analyzer (TG-DTG), and the analysis results showed that the Pd and Ni ions coordinated onto the OCMCS and formed a ligand with the –COOH group, amino groups, and –OH group on the OCMCS, and the EDS and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) analysis results showed that the loading amounts of Pd and Ni were approximately 8.3% and 8.9%, respectively. In the Heck reaction between aryl halides andn-butyl acrylate catalyzed by the prepared catalyst, the test results showed that the product yield followed the order of aryl iodide > aryl bromide > aryl chloride. Additionally, the product yield for the aryl iodide and aryl bromide could reach up to 99% and 96%, respectively. Moreover, the electron-withdrawing and electron-donating property of the group on the aryl also affected the product yield, and the product yield for aryl halides with electron-withdrawing groupp-NO2,p-CH3CO, andp-CHO was higher than that with electron-donating groupp-CH3.Keywords:O-carboxymethyl chitosan;biopolymer-supported catalyst;Pd-OCMCS;Ni-OCMCS;heck reaction

pH Sensitive phosphorylated chitosan hydrogel as vaccine delivery system for intramuscular immunization

Jianye Wei,Wei Xue,Xifei Yu,Xiaozhong Qiu,Zonghua Liu

In the field of immunotherapy, immune vaccinations have received more and more attention for disease prevention and treatment. In immune vaccination, efficient vaccine adjuvants are necessary due to the weak immunogenicity of vaccines. Some traditional vaccine adjuvants have been widely used but have shown obvious limitations such as poor biosafety. Therefore, researchers make a great effort to develop more functional novel immune adjuvants such as chitosan-based immune adjuvants. However, chitosan is poorly water soluble, which greatly limits its application as immune adjuvants, regardless of its good biocompatibility, biodegradability, and other biological activities. In this work, we prepared a water-soluble chitosan derivative phosphorylated chitosan (PCS) and evaluated its potential as a novel immune adjuvant. PCS was found to be pH sensitive: specifically, it was water soluble at pH < 7.0 but began to gel at pH >7.0. By virtue of this, neutral PCS aqueous solutions containing ovalbumin (OVA) antigen was intramuscularly injected into test mice, which would transform to an OVA-containing gel network for OVA immunization. The results showed that the use of 30 mg/mL PCS-based hydrogel as vaccine delivery system contributed to significantly higher level of antigen-specific immune responses, including higher level of antigen-specific IgG antibodies, IFN-γ and IL-4 cytokines secretion by splenocytes, as well as memory CD4+ and CD8+ T cells. In vivo imaging and immunohistochemistry assays suggest that the improved immunization efficacy may be attributed to the controlled release of antigen from injection site by PCS gel network, and then prolonged antigen stimuli to the immune system. From the results, PCS could be developed as a promising vaccine delivery system for immunotherapy.

Chitosan derivatives/reduced graphene oxide/alginate beads for small-molecule drug delivery

Kaihang Chen,Yunzhi Ling,Cong Cao,Xiaoyun Li,Xiao Chen,Xiaoying Wang

This work reported chitosan derivatives (CSD)/reduced graphene oxide (rGO) blending with alginate to prepare hydrogel beads for small-molecule drug delivery for the first time. At the beginning, graphene oxide (GO) was successfully reduced using diverse CSD as reducing and stabilizing agents via facile heating. Then the obtained CSD/rGO was blended with alginate and crosslinked into hydrogel beads in CaCl 2 solution. Finally, the beads were systematically evaluated as novel vehicles for pH-responsive small-molecule drug delivery. The optimal CSD/rGO/alginate beads showed a high drug-loading efficiency of 82.8% on small-molecule fluorescein sodium (FL), outstanding sustainable release of 71.6% upon 150   h at a physiological pH and quick-release of 82.4% drug content at 20   h in an acidic medium. Additionally, the cytotoxicity assay result suggested that the CSD/rGO/alginate beads showed negligible cytotoxicity to hepatic stellate cell lines, opening up possibilities for safe and efficient drug delivery.

Adsorption of RE3+ from aqueous solutions by bayberry tannin immobilized on chitosan

Xianying Qiu,Yueyue Shen,Ruilin Yang,Hongcheng Zhang,Shilin Zhao