INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
·
IF 6.953
Yuting Li,Yuhan Yang,Zhijun Huang,Zewei Luo,Cheng Qian,Yinjun Li,Yixiang Duan
Compared with high molecular weight chitosan (HMWC), low molecular weight chitosan (LMWC) has better solubility and biological activity. However, there is no quick and environmentally friendly to prepare low molecular chitosan. In this study, microwave induced plasma desorption/ionization (MIPDI) was used for the first time to prepare LMWC through the degradation processes of HMWC. The results showed that MIPDI has the most abundant ∙OH content at the gas-liquid interface, and the active particles represented by ∙OH can degrade chitosan with a molecular weight of 540 KDa into soluble chitosan (≤ 10 KDa), and the yield of soluble chitosan can reach 61% in 60 min. Moreover, a series of characterization results showed that the chain structure and crystal structure gradually degraded as the treatment time increased while the chemical structure of chitosan did not change significantly. Antibacterial experiments also indicated that the antimicrobial property of LMWC obtained by MIPDI degradation was improved. In short, this method has proven to be a new, fast and green processing method for the preparation of low molecular chitosan.
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高影响因子
MOLECULES
·
2021
·Vol. 26
·期 16
·5003
·
IF 4.412
Zhengyue Li,Xiuqiong Chen,Chaoling Bao,Chang Liu,Chunyang Liu,Dongze Li,Huiqiong Yan,Qiang Lin
It is common knowledge that pure alginate hydrogel is more likely to have weak mechanical strength, a lack of cell recognition sites, extensive swelling and uncontrolled degradation, and thus be unable to satisfy the demands of the ideal scaffold. To address these problems, we attempted to fabricate alginate/bacterial cellulose nanocrystals-chitosan-gelatin (Alg/BCNs-CS-GT) composite scaffolds using the combined method involving the incorporation of BCNs in the alginate matrix, internal gelation through the hydroxyapatite-d-glucono-δ-lactone (HAP-GDL) complex, and layer-by-layer (LBL) electrostatic assembly of polyelectrolytes. Meanwhile, the effect of various contents of BCNs on the scaffold morphology, porosity, mechanical properties, and swelling and degradation behavior was investigated. The experimental results showed that the fabricated Alg/BCNs-CS-GT composite scaffolds exhibited regular 3D morphologies and well-developed pore structures. With the increase in BCNs content, the pore size of Alg/BCNs-CS-GT composite scaffolds was gradually reduced from 200 μm to 70 μm. Furthermore, BCNs were fully embedded in the alginate matrix through the intermolecular hydrogen bond with alginate. Moreover, the addition of BCNs could effectively control the swelling and biodegradation of the Alg/BCNs-CS-GT composite scaffolds. Furthermore, the in vitro cytotoxicity studies indicated that the porous fiber network of BCNs could fully mimic the extracellular matrix structure, which promoted the adhesion and spreading of MG63 cells and MC3T3-E1 cells on the Alg/BCNs-CS-GT composite scaffolds. In addition, these cells could grow in the 3D-porous structure of composite scaffolds, which exhibited good proliferative viability. Based on the effect of BCNs on the cytocompatibility of composite scaffolds, the optimum BCNs content for the Alg/BCNs-CS-GT composite scaffolds was 0.2% (w/v). On the basis of good merits, such as regular 3D morphology, well-developed pore structure, controlled swelling and biodegradation behavior, and good cytocompatibility, the Alg/BCNs-CS-GT composite scaffolds may exhibit great potential as the ideal scaffold in the bone tissue engineering field.Keywords:alginate;bacterial cellulose nanocrystals;internal gelation;layer-by-layer electrostatic assembly;composite scaffolds;bone tissue engineering
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ChemCatChem
·
2021
·Vol. 13
·期 19
·4142-4150
·
IF 5.686
Jiaxin Liu,Peiyun Li,Renfeng Jiang,Xiucheng Zheng,Pu Liu
Graphical Catalytic Hydrolysis : Ruthenium nanoparticles with different dosages are immobilized on a naturally cationic polysaccharide polymer (chitosan, CS) via an adsorption-in situ reduction method for boosting AB hydrolysis. Catalyzed by the optimal Ru/CS catalysts, the turnover frequency is 338.1 min −1 in alkaline solution at 303 K and the apparent activation energy is 41.3 kJ mol −1 , which are superior to many results reported previously. Developing an advanced heterogeneous catalyst is essential for realizing high-performance ammonia borane (AB) hydrolysis, which is a safe and efficient way to generate hydrogen. In this work, a series of ruthenium (Ru) nanoparticles (NPs) immobilized on chitosan (CS) natural polymers are synthesized via an adsorption-in situ reduction method. Various analytical techniques, including XRD, XPS, FT-IR, SEM and TEM, are adopted to explore the structure-catalytic performance relationships of the obtained catalysts for hydrolysis of AB. Benefitting from the possible interaction between Ru NPs and the amino and hydroxyl groups in CS, the as-prepared catalysts exhibit excellent catalytic behavior for hydrogen generation from AB hydrolysis. Catalyzed by the optimal Ru/CS, the turnover frequency reaches up to 331.8 min −1 in NaOH solution at 303 K, and the corresponding apparent activation energy is 41.3 kJ mol −1 , which are superior to many results previously reported. This work demonstrates that the obtained Ru/CS is a promising and efficient catalyst for the hydrolysis of solid hydrogen storage materials.
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LWT-FOOD SCIENCE AND TECHNOLOGY
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2019
·
IF 3.714
Ying Ji,Xun Lin,Jicheng Yu
This study developed oxidized starch-chitosan complexes for the adsorption of procyanidins . Oxidized starch-chitosan complexes were prepared in two steps. Native cornstarch was first oxidized with a 2,2,6,6-tetramethyl piperidinyloxy (TEMPO) mediated reaction and then surface coated with chitosan to adsorb procyanidins. This study evaluated the morphologies and structures of starches in addition to the adsorption properties of procyanidins onto oxidized starch-chitosan complexes. The zeta potential revealed that the optimal weight ratio of oxidized starch and chitosan in the complexes was 1:0.4. The UV–visible spectrum of the complexes showed absorption spectra at about 255 nm, which has never been observed for oxidized starch. X-ray analysis and SEM indicated that the complexes changed the crystallinity and morphology of native starch. The ATR-FTIR spectra suggested that electrostatic interactions may be present between the -COO - of oxidized starch and –NH 3 + of chitosan. The adsorb experiments suggested that the oxidized starch-chitosan complexes could potentially be applied as carriers of bioactive compounds . This paper provides a good reference for an efficient adsorbent of polyphenols by oxidized starch-chitosan complexes.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
·
IF 3.131
Liang Ma,Xuejuan Shi,Xiaoxiao Zhang,Lili Li
Electrospun core-shell structured nanofibers have got wide attention due to their excellent properties and potential applications. Encapsulated CS in PCL to form the core-shell structured fibers would be a festival way to expanding the applications of biopolymers. In this work, the electrospun core-shell polycaprolacone/chitosan (PCL/CS) composite nanofibers were prepared by a stable emulsion system. Different from other reported works, the surfactant-free and low toxic water-in-oil emulsion was selected to form the electrospinning precursor. The high stability of the emulsion was achieved by adjusting the volume ratio of the solvents and the concentration of the polymers. PCL/CS fibers with different core to shell ratios were obtained via the adjustment of the concentration of CS and PCL in emulsion system. The distribution of the composition in the fibers was analyzed by FT-IR, XRD, EDS, XPS and WCA. Further, intact ultrafine CS fibers with a mean diameter of 143 ± 49 nm could be obtained after the removal of PCL shell, indicating the low diffusivity between core and shell solutions during emulsion electrospinning process. This study provided a promising method to fabricate natural polymer fibers which were difficult to electrospin.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Jingjing Wu,Hongqiang Li,Xuejun Lai,Zhonghua Chen,Xingrong Zeng
Piezoresistive pressure sensors with high sensitivity, fast response, and simplified signal collection play an important role in a wide variety of fields. However, most of them are water-sensitive and easily attacked by water, leading to serious signal distortion in practical application. Herein, we fabricated a conductive and superhydrophobic 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS) modified reduced graphene oxide@carbon nanotubes/chitosan (F-rGO@CNTs/CS) aerogel for piezoresistive pressure sensor. Benefiting from the porous structure of aerogel and the synergy of CNTs and rGO, the aerogel sensor achieved high sensitivity and fast response. Moreover, the sensor maintained a stable electrical resistance response after 1000 loading-unloading cycles. Importantly, owing to the rough structure constructed by CNTs and multi-pores and the low surface energy of FAS, the sensor possessed superhydrophobic property with a high water contact angle of 154°, and exhibited remarkable water repellency even during compression process. In addition, the sensor was successfully applied for detecting human behaviors from small-scale muscle movements to large-scale body motions. Our findings provide a new direction to fabricate functional and high-performance piezoresistive pressure sensor for various applications even under water or wet environment.
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高影响因子
Food Packaging and Shelf Life
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2019
·
IF 3.63
Thanakorn Yeamsuksawat,Jun Liang
The aim of this work was to produce the in-situ crosslinking emulsification chitosan film by the casting solution method and to study the effect of sodium tripolyphosphate (TPP), sodium citrate (CT), and glutaraldehyde (GLU) for the physical properties, barrier properties, mechanical properties, and release kinetics of chitosan film incorporated with α-tocopherol. The release of α-tocopherol to the 50% ethanol was also studied and the diffusion coefficient calculated by the Fickian diffusion models. From the results, the crosslinking agent decreased the film lightness and light barrier properties; in addition, it increases the greenness and yellowness of the film. The elongation at break (EB) and tensile strength (TS) tended to decrease when the film was crosslinked. This result can indicate that the crosslinking agent caused the chitosan networks to be linked and then affected the flexibility of the films. The crosslinking agent can increase the hydrophobicity and surface roughness of the film as shown in the increase of the contact angle values and SEM micrographs; instead, there was no significant difference in water vapor permeability values (WVP). The diffusion coefficient of α-tocopherol significantly decreased from when the film was crosslinked, and the slowest release occurred in glutaraldehyde (GLU) due to its ability to generate more crosslinking density that directly affects the mobility of α-tocopherol in the chitosan structure.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
·
IF 4.784
Meng He,Lei Shi,Guanzhe Wang,Zhonghan Cheng,Lin Han,Xinjiang Zhang,Chengshuang Wang,Jinshan Wang,Panghu Zhou,Guozhen Wang
Bulk homogeneous polyelectrolyte complex hydrogels (PCH) are difficult to prepare due to the flocculation effect between polyelectrolytes with opposite charges. Herein, novel chitosan/sodium polyacrylate (PAAS) polyelectrolyte complex hydrogels (CPG) were fabricated successfully by cross-linking chitosan and PAAS with epichlorohydrin (ECH) through inhibiting protonation effect of chitosan in alkali/urea aqueous solution. The swelling behaviors of CPG were studied systematically in different solutions. The equilibrium swelling ratio of chitosan hydrogel in water increased dramatically from 46.3 to 404.8 g/g by the introduction of PAAS. CPG exhibited different swelling ratios towards different pH solutions, physiological solutions and salt solutions with different concentrations, showing obvious smart responsive properties. Moreover, CPG hydrogels exhibited relatively high compressive strength , good biocompatibility and in vitro biodegradability . Therefore, this work provided a novel PCH and shed light on the fabrication of other PCH, showing potential applications in the fields of agriculture, foods, tissue engineering and drug delivery.
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2019
·
IF 6.361
Fangfang Xiao,Jianhua Cheng,Wen Cao,Cao Yang,Junfeng Chen,Zifen Luo
The use of chitosan combined with magnetic Loofah biochar (CMLB) was investigated for the removal of Cr(VI) and Cu(II) from aqueous solution. The modified biochar had higher Cr(VI) and Cu(II) adsorption capacity than that of pristine biochar. 40%-CMLB showed high Cr(VI) and Cu(II) adsorption capacity of 30.14 mg/g, and 54.68 mg/g, respectively. Adsorption reached equilibrium within 18 h. The study found that the experimental data showed the best fit for the pseudo-second-order kinetic model and Freundlich model. Additionally, after three reuse cycles, Cr(VI) and Cu(II) adsorption capacity by CMLB were 23.34 mg/g and 42.6 mg/g, respectively. XPS results indicated that ion exchange and surface complexation were the primary mechanisms for Cr(VI) and Cu(II) adsorption.
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JOURNAL OF HAZARDOUS MATERIALS
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2019
·
IF 7.65
Dalin Hu,Haoyu huang,Ran Jiang,Nan Wang,Hongping Xu,Yang-Guang Wang,Xiao-kun Ouyang
Residual diclofenac sodium (DS) in the environment is harmful to human health. A promising method for DS removal is the use of adsorbents functionalized with amino groups that can form an ionic bond with the carboxyl group of DS at a suitable pH. In this work, a novel composite adsorbent composed of cellulose nanocrystals (CNC) and chitosan (CS) has been synthesized and functionalized by ethylenediamine (ED) in both layers. Characterization methods, including scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectrometry, and X-ray photoelectron spectroscopy, were used to confirm the morphology and synthetic mechanism of the double- amino-functionalized adsorbent. Based on the optimization of adsorption conditions and modeling of the adsorption mechanism, the DS adsorption process on CNC-ED@CS-ED involves chemical adsorption, and the maximum adsorption capacity obtained from the Langmuir model is 444.44 mg/g. CNC-ED@CS-ED exhibits good adsorption capacity and high sustainability; thus, it is a promising composite material for the removal of DS from wastewater.
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Polymers
·
2019
·Vol. 11
·期 1
·95
·
IF 3.164
Chunhong Shi,Wenquan Sun,Yongjun Sun,Lei Chen,Yanhua Xu,Mengdan Tang
Carboxymethyl chitosan (CMCS), acrylamide, and methacryloxyethyltrimethyl ammonium chloride were used as co-monomers to produce a sludge dewatering agent carboxymethyl chitosan-graft-poly(acrylamide-methacryloxyethyltrimethyl ammonium chloride) (CCPAD) by UV-induced graft polymerization. Single-factor experiments and response surface methodology were employed to investigate and optimize the grafting rate, grafting efficiency, and intrinsic viscosity influenced by the total monomer concentration, CMCS concentration, cationic degree, pH value, and illumination time. The structure, surface morphology, and thermal stability of CCPAD were characterized by infrared spectroscopy, hydrogen nuclear magnetic resonance, X-ray diffraction, scanning electron microscopy, and differential thermal-thermogravimetry. The raw sludge with 97.9% water content was sourced from the concentrated tank of a sewage treatment plant and used in the sludge condition experiments. In addition, CCPAD was applied as the sludge conditioner to investigate the effects of cationic degree, intrinsic viscosity, and pH on the supernatant turbidity, moisture content, specific resistance to filtration, and sludge settling ratio. Moreover, the mechanism of sludge conditioning by CCPAD was discussed by examining the zeta potential and extracellular polymeric substance (EPS) content of the supernatant. The sludge dewatering results confirmed that CCPAD had excellent performance for improving sludge dewaterability.Keywords:chitosan-based flocculant;graft copolymerization;flocculation;sludge conditioning;dewaterability
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Marine Drugs
·
2019
·Vol. 17
·期 6
·365
·
IF 3.772
Qing Min,Jiaoyan Liu,Xiaofeng Yu,Yuchen Zhang,Jiliang Wu,Ying Wan
Local administration of platelet-derived growth factor-BB (PGDF-BB) and bone morphogenetic protein-2 (BMP-2) in a sequential release manner could substantially promote bone healing. To achieve this goal, a delivery system that could sustain the release of PGDF-BB and BMP-2 by way of temporal separation was developed. One type of PGDF-BB-encapsulated alginate microsphere and another type of BMP-2-encapsulated microsphere with a core-shell structure were respectively produced using emulsification methods. These two types of microspheres were then embedded into chitosan/glycerophosphate hydrogel for constructing composite gels. Some of them were found to be injectable at ambient temperature and had thermo-sensitive features near physiological temperature and pH. The optimally formulated composite gels showed the ability to control the release of PGDF-BB and BMP-2 in a sequential fashion in which PDGF-BB was released earlier than BMP-2. In vitro release patterns indicated that the release rates could be significantly regulated by varying the embedded amount of the factor-encapsulated microspheres, which can in turn mediate the temporal separation release interval between PGDF-BB and BMP-2. The released PDGF-BB and BMP-2 were detected to be bioactive based on their respective effects on Balb/c 3T3 and C2C12 cells. These results suggest that the presently developed composite gels have the potential for bone repair by synergistically utilizing the early chemotactic effect of PDGF-BB and the subsequent osteogenic and angiogenic functions of PDGF-BB and BMP-2.Keywords:microspheres;growth factor;composite hydrogel;sequential delivery;platelet-derived growth factor-BB;bone morphogenetic protein-2
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