INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2018
·
IF 3.909
Jingfeng Li,Lifang Chen,Zhiyun Meng,Guifang Dou
Chitosan has multiple biological activities, but a sensitive and rapid characterization method is yet to be developed for its further application. This study presented an optional mass spectrometry method for the characterization of chitosan. Nine kinds of chitosan (degree of deacetylation (DD), 63.08%–89.06% & MW, 106.1–485.0 kDa) were adopted for the method development. Most species of chitosan, detected by an ESI-MS technique, were observed below 1000 m/z , which seemed that only chito-oligosaccharide (COS) impurities were detected. Then, a sensitive UPLC-ESI-MS/MS method was established to assess the COS impurities in chitosan, and no COS impurities were detected. However, dissociation of chitosan and COSs in the ESI source were observed, and then the mass spectra patterns were deeply evaluated via an accurate Q-TOF mass spectrometer. Our research demonstrated that the mass spectra of COSs and chitosan resulted from the dissociation of glycosidic linkage and dehydration. Although the distribution of GlcN and GlcNAc units in these chitosan samples might be different, similar dissociation efficiencies were observed. Furthermore, good linearities were obtained between the intensities of product ions, detected by an UPLC-pseuedo-MS2 method, and DDs determined by conventional method. This method could be suitable for the DD determination and quantitative analysis of chitosan.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 136
·期 1
·46904
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IF 1.901
Saad Ahmed,Yangben Cai,Muhammad Ali,Santosh Khanal,Shiai Xu
In this study, we incorporated commercially available p -toluene sulfonic acid coated boehmite nanofillers (commercially known as OS 1 ) into the chitosan (CS) matrix to fabricate CS–OS 1 nanocomposite membranes with a high proton conductivity for fuel-cell applications. These nanocomposite membranes were characterized by Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, scanning electron microscopy, and thermogravimetric analysis. Their mechanical properties, water uptake, ion-exchange capacity, and proton conductivity were also determined. The results show that the incorporation of OS 1 to CS chains can inhibit the mobility of CS chains and, hence, enhance the thermal stability and mechanical properties of CS–OS 1 nanocomposite membranes. The composite membrane with 5 wt % OS 1 showed a proton conductivity of 0.032 S/cm; this was almost equal to that of commercially available Nafion 117. We concluded that CS–OS 1 nanocomposite membranes have potential for fuel-cell applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 46904.
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Materials Science & Engineering C-Materials for Biological Applications
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2018
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IF 5.08
Hongbo Suo,Zhen Gao,Lili Xu,Chao Xu,Dinghua Yu,Xinran Xiang,He Huang,Yi Hu
We developed magnetic chitosan nanoparticles (CS‑Fe 3 O 4 ) with mean diameter of 15–20 nm. Subsequently, these inorganic-organic composite nanoparticles were modified using an imidazole-based functional ionic liquid (IL). The prepared support (IL‑CS‑Fe 3 O 4 ), which was used to immobilize porcine pancreatic lipase (PPL), was characterized using Fourier transform infrared (FTIR) spectroscopy, vibrating sample magnetometry (VSM), thermogravimetry (TG), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Circular dichroism (CD) was used to analyze the secondary structure of immobilized PPL. The immobilized PPL (PPL‑IL‑CS‑Fe 3 O 4 ) exhibited 1.93-fold higher specific activity than PPL‑CS-Fe 3 O 4 when triacetin was used as the substrate, and showed 95 mg/g of lipase immobilization capacity and 382% of activity recovery. The residual activity of PPL‑IL‑CS‑Fe 3 O 4 was above 60% of the initial activity after incubation at 50 °C for 6 h, as was higher than that of PPL‑CS‑Fe 3 O 4 which showed 40% of the initial activity. In addition, PPL‑IL‑CS‑Fe 3 O 4 retained 84.6% of the initial activity after 10 cycles, whereas PPL‑CS‑Fe 3 O 4 retained only 75.5% activity. Furthermore, the kinetic parameters, apparent K m and V max of PPL‑IL‑CS‑Fe 3 O 4 were 2.51 mg/mL and 1.395 U/mg respectively, these results indicated that the immobilized PPL had better affinity towards the substrate, especially when the nanoparticles were modified by functional IL. Besides, the magnetic chitosan nanoparticles loaded with PPL were easily recovered. A novel, efficient, and practical method for enzyme immobilization was developed.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2019
·Vol. 136
·期 47
·48247
·
IF 2.188
Beijia Fu,Baoxiao Cheng,Xiaoqiang Jin,Xiaojiong Bao,Zhengke Wang,Qiaoling Hu
Chitosan-based single network hydrogels with imine bonds have excellent self-healing capability, while poor mechanical properties limit their applications. Here, chitosan-polyacrylamide-based double network hydrogels were prepared via in situ free-radical polymerization of acrylamide in the presence of N -carboxyethyl chitosan (CEC) and dibenzaldehyde-terminated telechelic poly(ethylene glycol), which had excellent mechanical properties, self-healing, and dual-responsive shape memory abilities. The maximum tensile strength and elongation at break could reach 460 kPa and 4600%, respectively. Meanwhile, owing to the reversibility of imine bonds, elongation and strength at break of hydrogels could heal by 84.2 and 93.2% under alkali stimulation at 35 °C, respectively. Furthermore, the hydrogels also had good shape memory abilities for pH-stimuli responsiveness of the imine bonds and metal ions stimuli responsiveness of CEC. The prepared chitosan-based functional hydrogels have great potential application prospects in tissue scaffolds, actuators, and wearable devices. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 48247.
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JOURNAL OF MICROENCAPSULATION
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2019
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IF 2.04
Tingting Chen,Shunying Li,Wenting Zhu,Zhi Liang,Qingbing Zeng
Polyelectrolyte complexes (PEC) provide new opportunities for controlled release system of drugs, and have potentials to address challenges on the way to effective oral insulin delivery. Here, an innovative pH-sensitive PEC for insulin oral administration was developed, which was formed by self-assembly of two oppositely charged nanoparticles (chitosan-coated nanoparticles and alginate-coated nanoparticles) through electrostatic interaction via optimised double emulsion method. The encapsulation efficiency of insulin-loaded alginate-coated and chitosan-coated nanoparticles were 81.5 ± 7.4% and 55.2 ± 7.0%, respectively, and the particle size of these nanoparticles were in 200–300 nm range. The pH-dependent morphology of PEC was observed by transmission electron microscopy. The PEC exhibited insulin release profile triggered by pH in vitro and was non-cytotoxicity against Caco-2 cell. The insulin-loaded PEC could decrease blood glucose levels effectively and prolong insulin release after oral administration to diabetic rats. The results illustrated that the as-prepared PEC may be employed as a potential oral insulin delivery system.
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POLYMER COMPOSITES
·
2018
·Vol. 40
·期 6
·2432-2440
·
IF 1.943
Chao Sheng,Yiming Zhou,Jiannan Lu,Xinyu Zhang,Guoxin Xue
A novel hydrogel with superior mechanical properties were prepared using chitosan chemical cross-linked with oxidized cellulose nanowhiskers (CNWs). An increased cross-linking degree (6–40%) between chitosan and oxidized CNWs was found with the increased oxidation level of CNWs. A series of experiments were performed to evaluate the effect of oxidation level of CNWs on hydrogel properties. The morphology results showed that the cross-linking reaction increased the hydrogels network density and the porous structure showed more compact and regular. Besides, the change in the morphology properties has an influence on hydrogels swelling behavior, exhibiting relatively reduced water content, and swelling ratio. The rheological measurements exhibited 263% and 394% improvements in storage modulus and loss modulus, respectively, and the maximum compressive stress confirmed an increasement by about 509%, were observed from the hydrogels cross-linked by oxidized CNWs, compared with noncross-linked hydrogels. Moreover, the resistance toward thermal degradation of the chitosan hydrogels was also increased by chemical cross-linking. POLYM. COMPOS., 40:2432–2440, 2019. © 2018 Society of Plastics Engineers
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
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2018
·Vol. 316
·期 2
·635-647
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IF 1.181
Liao Yun,Wang Meng,Chen Dajun
A novel three-dimensional porous polydopamine-functionalized attapulgite/chitosan (AT@PDA/CS) aerogel was designed and prepared for uranium(VI) adsorption, and its morphology and structure were characterized by TEM, SEM-EDS, XRD, FT-IR, Raman and XPS techniques. According to batch experiments, its adsorption equilibrium was reached within 40 min at pH 5.0. The adsorption isotherms was fitted well for Langmuir isotherm model and maximum adsorption capacity was 175.1 mg g −1 at 328 K. The thermodynamic analysis indicated that the adsorption was an endothermic and spontaneous process. Furthermore, the aerogel has superior absorption reusability and the removal efficiency was maintained at 78% after five adsorption–desorption cycles.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2015
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IF 1.098
Zujin Yang,Yanxiong Fang,Hongbing Ji
Microcapsules of salicylic acid (SA) with chitosan were prepared by spray drying method. Various analytical methods were used to characterize the nature of microcapsules. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of intermolecular interactions between chitosan and SA. Particle size analysis showed that the average size of microcapsules ranged from 2 to 20 μm. Scanning electron microscopy (SEM) studies indicated that the microspheres were spherical and had a relatively smooth surface. Microbiological assay of antibacterial activity for SA and its microcapsules was measured using different bacterial strains. It was found that the antibacterial activity of SA was improved after the formation of microcapsules. The in vitro release profile showed that the microcapsules could control SA release from 1 h to 4 h. Kinetic studies revealed that the release pattern follows Korsmeyer–Peppas mechanism. Enhanced antibacterial activity of the SA microcapsules was attributed to the synergistic effects of intermolecular hydrogen-bonding interactions N–H⋯O and O–H⋯O C between SA and chitosan. It was also confirmed by quantum chemical calculation.
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MONATSHEFTE FUR CHEMIE
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2014
·Vol. 146
·期 3
·465-474
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IF 1.347
Ma Wei,Dai Jiangdong,Dai Xiaohui,Da Zulin,Yan Yongsheng
Abstract Novel magnetic molecularly imprinted polymers (MMIPs) were prepared based on magnetic chitosan microspheres via a simple and effective method; the obtained MMIPs were used for selective recognition and fast separation of chloramphenicol from water. Fe 3 O 4 nanoparticles were uniformly wrapped into the chitosan by emulsion cross-linking method. Imprinted polymerization directly occurred on the surface of microspheres, and core–shell imprinted polymers were developed via in situ precipitation polymerization. The properties of obtained MMIPs were characterized by scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, X-ray diffraction, FT-IR, thermogravimetric analysis, and so on. The adsorption equilibrium data were well described by Langmuir isotherm model. Kinetic studies of adsorption showed that the equilibrium was reached within 60 min, and the pseudo-second-order kinetic model was used to fit the adsorption data well. This work can be regarded as a perfect combination of selective adsorption and magnetic separation, and the obtained MMIPs showed specific recognition and selectivity for chloramphenicol in the presence of competitive antibiotics. The obtained MMIPs showed good stability and regeneration property, which could be one of the most promising candidates for environmental pollution application. Graphical abstract
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Analytical Methods
·
2014
·Vol. 7
·期 4
·1387-1394
·
IF 1.938
Lu Lin,Hui-Ting Lian,Xiang-Ying Sun,Ya-Ming Yu,Bin Liu
A molecularly imprinted polymer (MIP) based sensor for detecting L-dopa was fabricated based on the composite of graphene (GR) and chitosan (CS). The microstructure and composition of the imprinted films characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Raman spectroscopy and electrochemical impedance spectroscopy (EIS) indicated that the modified film of GR-MIPs had been formed successfully. Electrochemical evaluation results showed that the sensor exhibited a satisfactory selectivity for molecular binding with an imprinting factor (IF) of 6.2 and a wide linear range from 0.4 μM to 100 μM with a low detection limit of 0.012 μM. This electrochemical sensor exhibited great promise for accurate determination of L-dopa in pharmaceutical preparations and human blood serum for recoveries ranging from 95.0 to 108.0%. Furthermore, compared to imprinted films without graphene doping, GR-MIPs showed a superior chiral sensing for L-dopa in the presence of D-dopa. The results reveal that the insertion of graphene brought about an enhanced sensitivity for chiral sensing and has the potential for application in chiral recognition.
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ANALYTICA CHIMICA ACTA
·
2013
·
IF 4.387
Jia Zhang,Ying Sun,Hua Zhang,Bo Xu,Hanqi Zhang,Daqian Song
This paper reports the utilization of triangular silver nanoplates (TSNPs) to enhance the sensitivity of surface plasmon resonance (SPR) biosensor. TSNPs modified with 3-mercaptopropinic acid (MPA) were simply mixed with chitosan and glutaraldehyde to form TSNPs/chitosan composite. The composite was deposited on Au film as immobilization substrate for SPR biosensor. The novel structures of TSNPs are preserved against etching by MPA and chitosan polymer. Moreover, chitosan cross-linked by glutaraldehyde enables antibody to be immobilized on fabricated substrate directly via Schiff alkali reaction. In the optimized conditions, the resulting biosensor based on TSNPs/chitosan composite shows a satisfactory response to bovine IgG in the concentration range of 0.075–40.00 μg mL −1 . While the biosensor based on chitosan without TSNPs shows a response in the concentration range of 0.6–40 μg mL −1 and the biosensor based on Au film shows a response in the concentration range of 2.5–40 μg mL −1 . The experiment results show that the sensitivity of SPR biosensor based on TSNPs/chitosan composite was significantly enhanced and the immobilization procedure of antibody was simplified.
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BIOSENSORS & BIOELECTRONICS
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2012
·
IF 5.602
Minggang Zhao,Jingyun Huang,Yu Zhou,Qi Chen,Xinhua Pan,Haiping He,Zhizhen Ye
A novel method of fabricating a free probe type nanoscale biosensor is first demonstrated. A free probe type biosensor based on a single one-dimensional (1D) mesoporous ZnO/Chitosan inorganic–organic hybrid nanostructure is constructed. The as-prepared biosensor exhibited excellent biosensing performance and was stable in solution due to its inorganic–organic hybrid structure. The special mesoporous nanostructure with protuberances favors enzymes loading and enhances electrical communication efficiency. The feasibility of employing a single 1D nanostructure as a separate free nanoprobe for biosensing is demonstrated. This kind of free probe type biosensor will not only provides a new tool for micro-targets detection in microcell and enzymatic studies, but also has the potential to be inserted into single cell or other microorganism for biological studies.
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