查找使用阿拉丁产品的科研文献

Novel hydroxyethyl chitosan/cellulose scaffolds with bubble-like porous structure for bone tissue engineering

Yaping Wang,Junmin Qian,Na Zhao,Ting Liu,Weijun Xu,Aili Suo

Hydrogels fabricated from natural polysaccharides may serve as ideal scaffolds for tissue engineering because of their similarity to the extracellular matrices. In this study, novel hydrogel scaffolds with bubble-like porous structure were prepared from hydroxyethyl chitosan (HECS) and cellulose (CEL) by a combination of chemical crosslinking, particle-leaching using silicon dioxide particles as porogen and freeze-drying method. The morphology, compression stress-strain curves, wettability, and swelling and rheological behaviors of the HECS/CEL scaffolds were characterized by SEM, mechanical test, contact angle measurement and rheometer. HECS/CEL scaffolds had good comprehensive performances and could reach equilibrium swelling state in water within 20s. The results from in vitro biocompatibility evaluated using SEM, live/dead cell viability and MTT assays demonstrated that the HECS/CEL scaffolds could well support the attachment, spreading and proliferation of osteoblastic MC3T3-E1 cells and showed good biocompatibility. Therefore, the novel HECS/CEL scaffolds may be promising for bone tissue engineering applications.

Ti4+-immobilized chitosan-coated magnetic graphene oxide for the highly selective enrichment of phosphopeptides

Yiman Zhao,Lingyi Zhang,Zhanying Chu,Zhichao Xiong,Weibing Zhang

For in-depth analysis of phosphorylated proteomics, the highly sensitive and selective capture of phosphopeptides from intricate biological samples is extremely significant. In this work, a late-model immobilized metal ion affinity chromatography (IMAC) material was fabricated and applied to enriching phosphopeptides from biological samples by abundant Ti4+ ions, which were chelated to crosslinked chitosan (CS) loaded on the surface of magnetic graphene oxide (GO) (denoted as mag GO–CS–Ti4+). The high amount of crosslinked CS endowed the IMAC material with highly hydrophilic properties and abundant active sites for Ti4+ ions on the surface. These characteristics ensure the great performance of mag GO–CS–Ti4+ in the selective enrichment of phosphopeptides from the tryptic digest of β-casein with high selectivity (phosphopeptides to non-phosphopeptides at a molar ratio of 1 : 400), high sensitivity (0.5 fmol), large enrichment capacity (66.6 mg g−1), prominent phosphopeptide recovery (93.11%), and excellent reusability. What's more, mag GO–CS–Ti4+ was applied to capturing phosphopeptides from real biological samples, human serum from both healthy people and patients and nonfat milk. The results successfully manifested that the mag GO–CS–Ti4+ could be a great affinity material for the enrichment of low-abundant phosphopeptides from biological samples.

Sequential delivery of chlorhexidine acetate and bFGF from PLGA-glycol chitosan core-shell microspheres

Ming-Mao Chen,Huan Cao,Yuan-Yuan Liu,Yan Liu,Fei-Fei Song,Jing-Di Chen,Qi-Qing Zhang,Wen-Zhi Yang

Wound treatment should meet the challenge both of preventing infection and promoting wound healing. To design a sequential delivery system for wound healing, PLGA-glycol chitosan (GC) core-shell microspheres containing chlorhexidine acetate (CHA) at the GC shell and bFGF in the core of PLGA microspheres were fabricated using emulsion-solvent evaporation method. SEM showed that the microspheres were all spherical in shape with a smooth surface. The average size of PLGA-GC microspheres increased due to the GC coating on the surface. The results of release profiles and fluorescence images indicated that PLGA-GC microspheres had an ability to deliver drugs in sequence. The CHA was rapidly released, whereas the proteins presented a sustained release. The release behavior could be modulated by changing the GC amount. Antibacterial assay and cell proliferation tests suggested that the released CHA and bFGF retained their antimicrobial activity and bioactivity during preparation. The microspheres exhibited non-cytotoxicity against 3T3 cells and had a good biocompatibility. These results demonstrated that PLGA-GC core-shell microspheres could be a promising controlled release system of delivering drugs and proteins in sequence for wound healing.

Enhanced biocompatibility and antibacterial property of polyurethane materials modified with citric acid and chitosan

Tian-Ming Liu,Xing-Ze Wu,Yun-Ren Qiu

“Stealthy” chitosan/mesoporous silica nanoparticle based complex system for tumor-triggered intracellular drug release

Min Zhang,Jia Liu,Ying Kuang,Qilin Li,Hongyu Chen,Haifeng Ye,Li Guo,Yanglin Xu,Xueqin Chen,Cao Li,Bingbing Jiang

Suitable protection strategies utilized in anticancer drug delivery systems enable carriers to reach their targeted positions and release drugs intracellularly more effectively. In this study, a novel “stealthy” chitosan (CHI)/mesoporous silica nanoparticle (MSN) based complex system, named DOX@MSN-SS-CHI-PEG, was developed for tumor-triggered intracellular drug release. CHI was applied to block the pores of MSNs to prevent premature drug release, whereas mPEG was grafted on the surface of the nanoparticles via a pH-sensitive benzoic imine linker to protect the carriers. As the pH of solid tumor tissues is slightly lower than that of normal tissues, mPEG could leave the nanoparticles to expose positively charged CHI at the surface, which enabled the nanoparticles to enter cancer cells more easily. The MSNs were covered by CHI via redox-sensitive disulfide bonds. As a result, the carriers could release the drug intercellularly to kill cancer cells owing to the high concentration of glutathione (GSH) in the cytosol. In vitro drug release studies at different GSH concentrations proved the redox-sensitivity of DOX@MSN-SS-CHI-PEG. mPEG leaving studies demonstrated that mPEG could leave the nanoparticles effectively at pH 6.0. The cytotoxicity and cell internalization behavior were also investigated in detail. In conclusion, the novel DOX@MSN-SS-CHI-PEG drug delivery system, which was “stealthy” in the physiological environment at pH 7.4 because of the protection of mPEG, was “activated” in weakly acidic tumor tissues to achieve tumor-triggered intracellular drug release; this system has great potential for cancer therapy.

Electrospun H4SiW12O40/chitosan/polycaprolactam sandwich nanofibrous membrane with excellent dual-function: adsorption and photocatalysis

Xiangxu Cui,Tingting Li,Shaowei Yao,Libao An,Yuqing Li,Zhi Zhou,Mengchao Guo,Zhiming Zhang

For comprehensive treatment of wastewater, an electrospun H4SiW12O40 (SiW12)/chitosan (CS)/polycaprolactam (PA6) sandwich nanofibrous membrane (SNM) with dual-functions of adsorption and photocatalysis was prepared to remove Cr(VI) and methyl orange (MO) from aqueous solution. The three layers of the SNM had good compatibility and thus no visible stratification phenomenon was observed in the SNM. Taking advantage of the merits of high porosity, good hydrophilicity, robust mechanical strength and superior water tolerance, the obtained SNM presented an excellent comprehensive performance with high adsorption capacity toward Cr(VI) (78.5 mg g−1), high photodegradation efficiency toward MO (96.7%) and good reusability. Based on the images of the SNM after Cr(VI) adsorption, the SiW12/PA6 layer (upper and bottom layer) was not affected in the adsorption process, which was consistent with our initial design. XPS analysis was carried out to investigate the mechanism of adsorption and photocatalysis. In the adsorption process, Cr(VI) was initially adsorbed on the CS/PA6 layer (intermediate layer), followed by the reduction of Cr(VI) to Cr(III) by the –NH2 of CS. The photocatalytic process was driven by the reductive pathway with faster degradation rate due to the electron donation from PA6 to SiW12. Although Cr(III) at the layer boundary was involved in the photocatalytic process, the photocatalytic activity of the SiW12/PA6 layer was almost not influenced. This work may provide a new and effective strategy to construct multifunctional nanofibrous membranes for the comprehensive treatment of wastewater.

Layer-by-Layer Assembled Chitosan-Based Antibacterial Films with Improved Stability under Alkaline Conditions

Fanqin Ji,Lina You,Lei Wang,Zhikai Liu,Yajun Zhang,Shanshan Lv

A “post-infiltration and subsequent photo-cross-linking layer-by-layer assembly” strategy was, for the first time, introduced to fabricate carboxylated chitosan (CCS) based antibacterial multilayer films with improved stability under alkaline conditions. Precursory polyelectrolyte multilayers were assembled from CCS and poly(allylamine hydrochloride) (PAH). 4,4′-Diazostilbene-2,2′-disulfonic acid disodium salt was then infiltrated to cross-link the multilayers under UV irradiation. Analysis by UV–vis spectra showed that absorbance at characteristic wavelengths of the multilayers increased almost linearly with number of CCS/PAH bilayers. AFM images indicated that surfaces of the cross-linked multilayers were rather uniform and stable against basic treatments. Surface wettability of the multilayers was determined by water contact angle measurements. The multilayers exhibited reasonable antibacterial properties against Gram-negative E. coli, demonstrating that the multilayers were active in preventing bacterial growth and represented a novel type of antibacterial films with improved stability under alkaline conditions. These results open new possibilities for building functionalized architectures onto polyelectrolyte multilayer films.

Enhanced Therapeutic Efficacy of Doxorubicin for Breast Cancer Using Chitosan Oligosaccharide-Modified Halloysite Nanotubes

Jing Yang,Yanping Wu,Yan Shen,Changren Zhou,Yi-Fang Li,Rong-Rong He,Mingxian Liu

Halloysite nanotubes (HNTs) are natural aluminosilicates with unique hollow lumen structure, also having high specific area, good biocompatibility, nontoxicity, and low price. Here, we designed a chitosan oligosaccharide-grafted HNTs (HNTs-g-COS) as a doxorubicin (DOX) carrier for treating breast cancer both in vitro and in vivo. The structure of HNTs-g-COS was first characterized by various methods. HNTs-g-COS showed positively charged surface and improved hemocompatibility. DOX-loaded HNTs-g-COS (DOX@HNTs-g-COS) released in cell lysate in a controlled manner. The IC50 value of DOX@HNTs-g-COS toward MCF-7 cells was 1.17 μg mL–1, while it was 2.43 μg mL–1 for free DOX. DOX@HNTs-g-COS increased the apoptosis effects of MCF-7 cells as shown in flow cytometry results. Also, reactive oxygen species of cells induced by DOX@HNTs-g-COS were drug-dose-dependent. DOX@HNTs-g-COS could enter the MCF-7 cells and induce mitochondrial damage as well as attack the nuclei. The in vivo antitumor effect of DOX@HNTs-g-COS was investigated in 4T1-bearing mice. The tumor-inhibition ratio of DOX@HNTs-g-COS was 83.5%, while it was 46.1% for free DOX. All mice treated with DOX@HNTs-g-COS survived over 60 days. DOX@HNTs-g-COS showed fewer ruptured cardiomyocytes and no obvious systemic toxicity. Therefore, the rational designed HNTs nanocarrier for chemotherapy drug showed promising applications in tumor treatment.

Quaternized carboxymethyl chitosan/organic montmorillonite nanocomposite as a novel cosmetic ingredient against skin aging

Kaihang Chen,Binzhao Guo,Jiwen Luo

It is of technical and economic importance to develop an effective cosmetic ingredient against skin aging through low-cost and facile production. This study developed a polymer/layered silicate nanocomposite as cosmetic ingredient against skin aging. Firstly, quaternized carboxymethyl chitosan (QCMC)/organic montmorillonite (OMMT) nanocomposite (QCOM) was fabricated via solution-induced intercalation. QCOM with different mass ratios of QCMC to OMMT were studied by various characterizations as well as moisture-adsorption and retention activities and UV-protection capacity. QCOM was then added into a cosmetic formulation to prepare a cosmetic cream. And the evaluation of its efficacy about skin care was conducted. The results showed that the optimal QCOM had better moisture-adsorption and retention behaviors than hyaluronic acid, and QCOM solution displayed good UV-protection ability. Furthermore, the QCOM-containing cosmetic cream meets the hygienic standard for cosmetics; it has negligible dermal irritation and a prominent moisture-retention efficacy on human stratum corneum.

Thermosensitive hydrogel loaded with chitosan-carbon nanotubes for near infrared light triggered drug delivery

Xia Dong,Chang Wei,Jie Liang,Tianjun Liu,Deling Kong,Feng Lv

Controlled drug release with on demand is an important challenge for drug delivery. Near-infrared (NIR) light triggered drug delivery reflected the development of a significant strategy to control drug release based on photothermal effects. Herein, a sustained and controlled drug delivery system was developed based on a PCL–PEG–PCL thermosensitive hydrogel combined with chitosan-multiwalled carbon nanotubes for a near infrared light triggered drug delivery. Carbon nanotubes that incorporate hydrogel can enhance the sustained effect of drug delivery by a dual-stage release and allow drug delivery by controlling light irradiation. This in situ photothermal process was monitored by thermal imaging and the controlled drug delivery of doxorubicin was tracked in real-time by fluorescence imaging in vivo based on the fluorescence ability of the drug using nude mice as models. The results suggest that the photothermal effect of the carbon nanotubes can disrupt the structure of the hydrogel with a gel–sol transition, triggering the release of the drug from the sustained drug delivery system by NIR irradiation while responding on demand. The sustained and controlled drug delivery has the potential to implement the accurate administration of hydrogel-based drug delivery systems.

Removal of ciprofloxacin from aqueous solution by a magnetic chitosan grafted graphene oxide composite

Fei Wang,Baoshan Yang,Hui Wang,Qixuan Song,Fengjiao Tan,Yanan Cao

A novel magnetic chitosan grafted graphene oxide nanocomposite (MCGO) was prepared and characterized using vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), and Brunauer Emmett Teller (BET) surface area. The adsorption performance and mechanisms of MCGO for the removal of ciprofloxacin (CIP) from water were evaluated. Adsorption kinetics followed the pseudo-second-order model. The adsorption isotherms data was well described by both Freundlich model and Langmuir model. The isotherm results showed that the maximum adsorption capacity (q m ) was 282.9   mg   g −   1 . The initial solution pH and ionic strength significantly influence the CIP adsorption. The removal efficiency decreased at pH   7 and 9. The presence of Na (200   mM) and Ca (10   mM) significantly reduced the adsorption of CIP. The adsorption of CIP was mainly controlled by electrostatic attraction and π-π electron interaction. Moreover, MCGO could be reused after the regeneration treatment and the removal capacity was about 72% of the initial adsorption capacity after being used four times.

Adsorptive recovery of palladium(II) from aqueous solution onto cross-linked chitosan/montmorillonite membrane

Jian Liu,Liuchun Zheng,Yaowei Li,Michael Free,Mingzhu Yang

A cross-linked chitosan/montmorillonite (CCTS-M) membrane was prepared successfully with a glutaraldehyde cross-linker, and then was characterized by FTIR, XRD, SEM/EDX, TG/DTG and XPS. The materials were used for removing palladium(II) from aqueous solutions. The effect of variable parameters including initial pH, contact time, initial concentration, and temperature were investigated. The results showed that the maximum capacity of the membrane was 193 mg g−1 at pH 2. This article not only described the adsorption behavior but also suggested isotherms, the kinetics data were best modeled using pseudo-second-order model, and the Langmuir isotherm model could fit the experimental data well. The thermodynamic parameters ΔG° (<0) and ΔH° (>0) indicated that the adsorption was a spontaneous and endothermic process. FTIR and XPS techniques confirmed that the –NH3+, –NH2 and CN– functional groups in the CCTS-M membrane played prominent roles in the adsorption process. Our results revealed that the membrane could be a promising adsorbent for the recovery of palladium.