查找使用阿拉丁产品的科研文献

Simultaneous detection and removal of cobalt ions from aqueous solution by modified chitosan beads

Zhuang S. T.,Yin Y. N.,Wang J. L.

Abstract In this paper, we modified chitosan beads in order to simultaneously detect and adsorb Co 2+ from aqueous solution. Firstly, 4-(5-chloro-2-pyridylazo)-1,3-phenylenediamine (5-Cl-PADAB) was used as selective probe for Co 2+ with color changing from yellow to pink, and the UV–Vis spectra showed that the λ max changed from 439 to 504 nm. Then a novel biomaterial was synthesized with 5-Cl-PADAB (metal indicator), chitosan (biosorbent) and EDTA anhydride (cross-linker and chelating agent). The analysis of Fourier transform infrared and energy-dispersive X-ray spectra proved that 5-Cl-PADAB and EDTA were successfully connected to chitosan. The modified chitosan bead was selective probe for Co 2+ with a remarkable color change from white to pink, and the UV–Vis spectra showed that the λ max changed from 441 to 459 nm. The adsorption of cobalt ions onto the modified chitosan beads followed pseudo-second-order ( R 2  = 0.99) kinetics and the Langmuir isotherm model ( R 2  = 0.80). Comparing with chitosan beads, the q e of the modified one increased from 2.00 to 7.97 mg/g. The modified chitosan beads are promising biomaterial for simultaneous detection and removal of Co 2+ from aqueous solution. Graphical Abstract

Chiral stationary phases based on chitosan bis(methylphenylcarbamate)-(isobutyrylamide) for high-performance liquid chromatography

Sheng Tang,Qin Bin,Wei Chen,Zheng-Wu Bai,Shao-Hua Huang

A series of chitosan bis(methylphenylcarbamate)-(isobutyrylamide) derivatives were synthesized by carbamylating chitosan isobutyrylamide with different methylphenyl isocyanates. Then the prepared chitosan derivatives were coated onto 3-aminopropyl silica particles, resulting in a series of new chiral stationary phases (CSPs) for high-performance liquid chromatography. It was observed that the chiral recognition abilities of these coated-type CSPs depended very much on the substituents on the phenyl moieties of the chitosan derivatives, the eluent composition, as well as the structure of racemates. As a typical example, the eluent tolerance of the prepared CSP with the best enantioseparation ability was investigated in detail, and the results revealed that the CSP exhibited extraordinary solvent tolerance and could still work without significant loss in enantioseparation capability after being flushed with chloroform (100%), ethyl acetate (100%) and even THF/ n -hexane (70/30, v/v), while the traditional coated-type CSPs based on the cellulose and amylose derivatives, such as cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) and amylose tris(3,5-dimethylphenylcarbamate) (ADMPC), might be dissolved or highly swollen in these eluents. Therefore, the application of the resultant CSPs could address the problem of the dissolution and high swelling of traditional coated-type CSPs in some unusual eluents, broadening the possibility of eluent choice. In addition, a comparison of the prepared CSPs with the well known CDMPC- and ADMPC- based CSPs concerning the chiral recognition ability was also made. Separation performances achieved on the as-prepared CSPs in different eluents were found to be even superior to CDMPC- and ADMPC-based CSPs for the tested chiral compounds. In summary, we could safely draw the conclusion that the CSPs derived from chitosan isobutyrylamide derivatives were capable of excellent chiral recognition ability, and meanwhile possessed satisfactory eluent tolerance in a wider range of solvents.

Preparation and biological activity studies of resveratrol loaded ionically cross-linked chitosan-TPP nanoparticles

Jie Wu,Yaping Wang,Hao Yang,Xiangyu Liu,Zhong Lu

Nanoparticles with size range of 10–500   nm can be efficiently delivered into cancer cells by the Enhanced Permeability and Retention (EPR) effect. Here, we prepared resveratrol (Res) loaded chitosan (CS) nanoparticles with the size of 172–217   nm by an ionic cross-linking method, with sodium tripolyphosphate (TPP) as the cross-linking agent, to improve the stability, solubility and tumors targeting of the natural anti-cancer drug Res. The prepared Res loaded CS-TPP nanoparticles presented long-term storage stability and UV light stability. The cumulative drug release from nanoparticles in mimetic tumor tissue condition (pH 6.5) was higher than that in physiological condition (pH 7.4). Further, Res-loaded CS-TPP nanoparticles maintained the antioxidant activity of Res even after UV light irradiation. Cell viability study shows that the as prepared drug loaded nanoparticles had similar antiproliferative activity on hepatocellular carcinoma cells SMMC 7721 and lower cytotoxicity on normal hepatocyte cells L02 compared with free Res. Fluorescence microscopy observation revealed that the nanoparticles were efficiently taken in by SMMC 7721 cells. This work indicates the potential use of drug loaded CS-TPP nanoparticles for the efficient delivery of bioactive Res for chemotherapy.

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.

Selective adsorption and separation of gadolinium with three-dimensionally interconnected macroporous imprinted chitosan films

Zheng Xudong,Liu Enli,Zhang Fusheng,Dai Jiangdong,Yan Yongsheng,Li Chunxiang

We successfully prepared three-dimensionally interconnected macroporous imprinted chitosan films (3DIM-IFs) by template-assisted assembly. Imprinted chitosan films exhibiting an interconnected macroporous structure are used as adsorbents for efficient and selective adsorption of gadolinium ions (Gd(III)). Saturation adsorption capacity of 3DIM-IFs for Gd(III) is up to 51.36 mg g −1 at 298 K, which is significantly higher than adsorption capacities for most reported Gd(III) imprinted adsorbents during recent years. Because of highly selective imprinted sites, imprinted films possess significant selectivity of Gd(III) than other rare earth ions. Moreover, 3DIM-IFs can be easily and rapidly retrieved without the need of additional centrifugation or filtration, greatly facilitating the separation process. Reusability tests demonstrated that the materials can be repeatedly used without significant loss in adsorption capacity, enhancing their potential application for recovery of Gd(III).

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.

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.

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.

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

Self-assembled nanoparticles based on amphiphilic chitosan derivative and arginine for oral curcumin delivery

Mazhar Ali Raja,Shah Zeenat,Muhammad Arif,Chenguang Liu

Curcumin (Cur) is a striking anticancer agent, but its low aqueous solubility, poor absorption, hasty metabolism, and elimination limit its oral bioavailability and consequently hinder its development as a drug. To redress these limitations, amphiphilic chitosan (CS) conjugate with improved mucoadhesion and solubility over a wider pH range was developed by modification with hydrophobic acrylonitrile (AN) and hydrophilic arginine (Arg); the synthesized conjugate (AN–CS–Arg), which was well characterized by Fourier transform infrared and 1H nuclear magnetic resonance spectroscopy. Results of critical aggregation concentration revealed that the AN–CS–Arg conjugate had low critical aggregation concentration and was prone to form self-assembled nanoparticles (NPs) in aqueous medium. Cur-encapsulated AN–CS–Arg NPs (AN–CS–Arg/Cur NPs) were developed by a simple sonication method and characterized for the physicochemical parameters such as zeta potential, particle size, and drug encapsulation. The results showed that zeta potential of the prepared NPs was 40.1±2.81 mV and the average size was ~218 nm. A considerable improvement in the aqueous solubility of Cur was observed after encapsulation into AN–CS–Arg/Cur NPs. With the increase in Cur concentration, loading efficiency increased but encapsulation efficiency decreased. The in vitro release profile exhibited sustained release pattern from the AN–CS–Arg/Cur NPs in typical biological buffers. The ex vivo mucoadhesion study revealed that AN–CS–Arg/Cur NPs had greater mucoadhesion than the control CS NPs. Compared with free Cur solution, AN–CS–Arg/Cur NPs showed stronger dose-dependent cytotoxicity against HT-29 cells. In addition, it was observed that cell uptake of AN–CS–Arg/Cur NPs was much higher compared with free Cur. Furthermore, the in vivo pharmacokinetic results in rats demonstrated that the AN–CS–Arg/Cur NPs could remarkably improve the oral bioavailability of Cur. Therefore, the developed AN–CS–Arg/Cur NPs might be a promising nano-candidate for oral delivery of Cur.

Self-assembled high-strength hydroxyapatite/graphene oxide/chitosan composite hydrogel for bone tissue engineering

Peng Yu,Rui-Ying Bao,Xiao-Jun Shi,Wei Yang,Ming-Bo Yang

Graphene hydrogel has shown greatly potentials in bone tissue engineering recently, but it is relatively weak in the practical use. Here we report a facile method to synthesize high strength composite graphene hydrogel. Graphene oxide (GO), hydroxyapatite (HA) nanoparticles (NPs) and chitosan (CS) self-assemble into a 3-dimensional hydrogel with the assistance of crosslinking agent genipin (GNP) for CS and reducing agent sodium ascorbate (NaVC) for GO simultaneously. The dense and oriented microstructure of the resulted composite gel endows it with high mechanical strength, high fixing capacity of HA and high porosity. These properties together with the good biocompatibility make the ternary composite gel a promising material for bone tissue engineering. Such a simultaneous crosslinking and reduction strategy can also be applied to produce a variety of 3D graphene-polymer based nanocomposites for biomaterials, energy storage materials and adsorbent materials.