Green Synthesis and Catalysis
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2022
·
IF 0
Mariam Iqbal,Yuefeng Deng,Qiaoyue Chen,Chengli Yang,Yihui Zhu,Ziqian Chen,Jianjun Wang,Kaishun Hu,Guanya He,Dali Li
Nanotechnology has become the most promising domain to boost the efficiency of enzymes. Enzymes are vital as a green catalyst in many industries, food, pharmaceutical and biomedical, etc. The immobilization process of the enzyme increases its catalytic properties. In this research, a novel method is presented to describe the effect of nano-calcium carbonate on the characteristics of immobilized β -glucosidase, which was extracted from the Agrocybe aegirit . The nano-CaCO 3 was produced using the eco-friendly natural deep eutectic solvent. The pure nano -CaCO 3 was observed as vaterite, with a size of about 300 nm. The nano-calcium carbonate was coated by a natural polymer sodium alginate compound and then adsorbed chitosan. Further, this obtained composite is cross-linked by the bioactive genipin to immobilize the β -glucosidase. The enzyme/protein loading ratio to the supports was 1:4, respectively. The recovery efficiency of immobilized β -glucosidase was 89.3%, and immobilization yield was 96.452%. Chitosan-coated nano-CaCO 3 was used as a carrier for immobilization of β -glucosidase to improve its stability and reusability. In addition to stability and reusability, pH tolerance, temperature tolerance, and enzyme kinetics are the significant parameters that illustrate the proficiency of an immobilized enzyme. The measured optimal enzymatic reaction conditions for the immobilized β -glucosidase were 50 °C and pH 6. Furthermore, it has shown noticeable improvements in thermo-stability and pH tolerance. Temperature tolerance was observed 50% to the initial activity of the immobilized enzyme even after the 3 h of incubation at 50 °C, while pH tolerance was noticed more than 50% and 40% at pH 7 and 8, respectively. The K m and V max values of free and immobilized β -glucosidase to 4-nitrophenyl β -D-glucopyranoside were 1.549 μmol/L/min, 0.346 mmol/L and 0.532 μmol/L/min, 0.080 mmol/L, respectively. The immobilized β -glucosidase retains its storability 80% even after 30 days of storage at 4 °C and maintains 93.1% of its residual activity by reusing up to 10 cycles.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2024
·
IF 4.1
Feng Wen-Jun,Wu Yan-He,Liu Xiao-Yang,Wang Zheng-Ke
Shear-thinning hydrogels have emerged for endoscopic submucosal dissection, while wound intervention after surgery has rarely been mentioned. Herein, a catechol-modified chitosan hydrogel with shear-thinning property was developed for simultaneously facilitating endoscopic submucosal dissection and postoperative wound healing. Benefiting from the shear-thinning and self-healing characteristics, the asprepared hydrogel showed easily endoscopic injectability. It also performed very well as submucosal cushion, which could remain above 70% after injection for 120 min in ex vivo porcine large intestine model. In fact, the cushion height of normal saline dramatically decreased to 46% of the initial height at 30 min. Ag nanoparticles encapsulated into the network endowed the hydrogel with almost reached 100% antibacterial effect against E. coli and S. aureus . The hemolysis ratio of the hydrogel was calculated to be as low as 0.8%. Combined with good hemocompatibility and cytocompatibility, the as-prepared hydrogel displayed much higher in vivo wound closure and healing efficacy than normal saline. These results demonstrated the superiority of the shear-thinning chitosan hydrogel in facilitating clinical endoscopic submucosal dissection surgery.
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DOI
高影响因子
Food Packaging and Shelf Life
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2022
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IF 8.749
Yingping Lai,Weitong Wang,Jiajia Zhao,Song Tu,Yingwu Yin,Liyi Ye
This work aims to develop degradable packaging films based on chitosan (CS) and Na-montmorillonite (MMT). The effect of citric acid (CA) on the properties of prepared films (MCS/CAs) was also investigated. MMT shows excellent compatibility in CS. Results from Fourier transform infrared spectroscopy , scanning electron microscopy , and thermogravimetric analysis indicated an improvement in the structural and thermal properties of the films after incorporating MMT into the CS matrix. Despite the reduced tensile strength , the composite films with CA loaded exhibited better swelling resistance and higher elongation at break (68%). MCS/CA-c (loaded with 80% CA) was employed to package cherry tomatoes so as to improve its conservation. Results showed improved physical/chemical properties (weight loss ratio, total soluble solids, titratable acidity, and ascorbic acid) of wrapped cherry tomatoes. Therefore, results reveal the potential of MCS/CAs films as degradable packaging material .
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2016
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IF 3.138
Xinyi Zhu,Liping Bao,Yong Wei,Jiangquan Ma,Yong Kong
Sodium carboxymethyl cellulose (NaCMC) and chitosan (CS) are successfully combined via amidation, and the obtained product, CMC-CS-A, is used for the adsorption of toxic indigo blue (IB) for the first time. The results of control experiments indicate that the adsorption performance of CMC-CS-A is superior to that of NaCMC, CS, and the composites of NaCMC and CS integrated via electrostatic attractions (CMC-CS-E), which can be attributed to the unique interconnected porous network structure of the as-prepared CMC-CS-A. The mass fraction of CS in the CMC-CS-A is also investigated to achieve the best adsorption of IB, and it reveals that satisfactory removal of IB can be achieved at the CMC-CS-A (50 wt%). Important parameters such as contact time, temperature and initial concentration are discussed in detail in this work. Finally, adsorption isotherms and adsorption kinetics are investigated and compared by using classic models, and the results indicate that the adsorption fits well with the Langmuir isotherm model and the pseudo-second-order kinetic model. It opens a new avenue for the effective and convenient treatment of textile wastewater with integrated natural biopolymers.
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高影响因子
Materials Research Express
·
2019
·Vol. 6
·期 7
·075404
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IF 1.449
Li Chen,Hao Jiang,Yaomin Li,Bhahat Lawlley Zimba,Xunzhi Yu,Chang Chen,Guoxi Xiong,Qingzhi Wu
In this work, pure chitosan (CS) nanofibrous membranes were successfully fabricated by electrospinning using the mixed solvent of trifluoroacetic acid (TFA) and dichloromethane (DCM). The influences induced by both the ratio of TFA and DCM and the concentration of CS in the electrospinning solution were analyzed. In order to improve the mechanical properties of pure CS nanofibrous membranes, graphene oxide (GO) nanosheets were incorporated into the CS nanofibers. The results show that the incorporation of GO nanosheets into CS nanofibers significantly improved both the tensile strength and Young's modulus of CS nanofibrous membranes. When the content of GO was 0.8%, the tensile strength and Young's modulus of CS/GO nanofibrous membrane were enhanced approximate 2 and 3 times, respectively, compared with that of pure CS nanofibrous membranes. There resulst provide promising potential for CS/GO nanofibrous membranes in biomedical applications, such as tissue engineering, wound healing, and drug delivery.
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
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IF 4.784
Kewang Zheng,Sa Xiao,Wei Li,Wei Wang,Hujian Chen,Fan Yang,Caiqin Qin
Edible films from chitosan (CH) containing various amount of acorn starch (AS) and eugenol (Eu) were developed by casting and solvent-evaporation method, and their physico-chemical, barrier, antimicrobial, antioxidant and structural properties were also investigated. The experimental data showed that an appropriate proportion of AS could improve the mechanical and barrier properties of the film, and the incorporation of Eu in the film significantly improved the flexibility, barrier, hydrophobicity , antimicrobial and antioxidant properties. The results showed that the optimum comprehensive properties of the film were obtained when the mass ratio of AS to CH was 0.9 and the content of Eu was 9%. Possible intermolecular interactions between CH, AS and Eu were confirmed by Fourier-transform infrared spectroscopy (FTIR). SEM indicated that a good compatibility was present between CH and AS, and Eu was well emulsified and dispersed in the film matrix network. TG and DTG curves further confirmed Eu present in the film matrix network. Such edible films can provide new ways for packaging industries in developing active packaging materials.
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高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2016
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IF 2.76
Zhengyang Li,Tingting Li,Libao An,Huan Liu,Linnan Gu,Zhiming Zhang
Chitosan/polycaprolactam (PA6) nanofibrous filter paper (NFP) was prepared by electrospinning technique. Characterization with Fourier transformation infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) indicated that there was weak interaction (hydrogen bonds) between PA6 and chitosan, and the average diameter of the composite nanofibers decreased as the chitosan content was increased. The maximum adsorption capacity of Cr(VI) on the NFP via filtration (114.7 mg g −1 ) was much higher than that via static adsorption (81.7 mg g −1 ) and shaking adsorption (80.7 mg g −1 ). Because the Cr(VI)-containing solution was forced to flow through the whole membrane in filtration, the chelation sites inside the membrane could be exploited, leading to the enhancement of the Cr(VI) adsorption. The hydrogen bonds between chitosan and PA6 could enhance the mechanical strength and the acid fastness of the NFP. Therefore, the NFP desorbed by H 2 SO 4 can be well reinstated, and the adsorption capacity of Cr(VI) decreased slightly (only 17.9%) after three filtration cycles. On the basis of X-ray photoelectron spectroscopy (XPS) analysis, the possible mechanism for the Cr(VI) removal was that Cr(VI) was initially adsorbed on the NFP due to the electrostatic attraction, and subsequently reduced to the less toxic form Cr(III) by the amino groups of chitosan.
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高影响因子
Desalination and Water Treatment
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2014
·
IF 0.987
Qian Liu,Bingchao Yang,Lujie Zhang,Ruihua Huang
A multifunction adsorbent, activated carbon (AC)/chitosan composite, was synthesized by incorporating AC into chitosan based on the ratio of AC to chitosan being 1/1. The simultaneous adsorption of aniline and Cu2+ from aqueous solution onto AC/chitosan composite was investigated by a batch procedure. These results showed that an adsorbent dosage of 0.3 g was appropriate, and a contact time of 210 min was convenient for reaching adsorption equilibriums for aniline and Cu2+. The simultaneous adsorption of aniline and Cu2+ was realized in a wide pH range. The adsorption process obeyed the pseudo-second-order kinetic model. The adsorption behaviors of aniline and Cu2+ followed Freundlich and Langmuir, respectively. No obvious competitive adsorption existed between Cu2+ and aniline.
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DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Chengcheng Ma,Jianguo Liu,Qi Wang,Wei Wang
The oxetane-substituted chitosan-polyurethane (OXE-CHI-PUR) film was synthesized using a simple, fast, and low-cost process, which is attractive for its many applications in the fields of self-healing anticorrosion. In this work, the OXE-CHI-PUR films with outstanding anticorrosion and self-healing performances were incorporated in epoxy resin coatings. SEM confirmed that the diameter of the OXE-CHI-PUR network film was approximately 380 μm (±4 μm). FT-IR measurement proved that successful synthesis of the OXE-CHI-PUR network film. It is visually observed through the confocal laser scanning microscope that the scratched OXE-CHI-PUR coating has a self-healing tendency with UV irradiation. The electrochemical impedance spectroscopy (EIS) experiments analyzed the self-healing performance of OXE-CHI-PUR coating. The results of EIS and 14 days’ seawater immersion tests revealed that the coating containing OXE-CHI-PUR films showed high anticorrosion performance and exhibited self-healing capabilities due to the influence of light and heat.
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高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
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2018
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IF 1.454
Chuandong Zhang,Jiangquan Ma,Yun Zhao,Zhengping Li,Wenjie Liu,Chao Yao
In this article, highly efficient magnetic chitosan nanoparticles were prepared by the glutaraldehyde cross-linking method and then chemically-modified with amino groups through reaction between triethylenetramine and glycidyl methacrylate. The adsorption kinetics and isotherms of these novel adsorbents fit the pseudo-second-order model and the Langmuir model. The maximum adsorption capacities were 293 mg/g at pH = 4.3 and t = 1.4 hours. The rate-limiting step was the chemical adsorption. Further recycling experiments showed that the adsorbent provided the potential regeneration and reuse after adsorbing Cu2+. All the experimental results demonstrated that the adsorbent had a potential application in Cu2+ removal from wastewater.
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2021
·
IF 6.953
Binqing Zhao,Qi Zhou,Chenxi Lou,Xinpeng Jin,Wei Li
Carbon dioxide (CO 2 ) assisted synthesis of water-soluble silver nanoparticle with a narrow particle size distribution is reported here based on the phase-inversion procedure. Bio-derived chitosan (CS) is used to stabilize the metal nanoparticles according to its abundant functional groups. Formic acid is employed as both a solvent (for the polymer) and a reductant for in-situ reducing the silver precursor along with the solvent evaporation. CO 2 is utilized to combine with the amino groups of CS, reducing the viscosity of chitosan/formic acid solution and limiting the formation of hydrogen bonds . This promotes the stabilization and reduction efficiency of silver nanoparticles. In particular, 100% of Ag metal nanoparticles with the size of 7.5 ± 2.3 nm is successfully synthesized with the assistance of CO 2 . Interestingly, the synthesized CS/Ag nanocomposites are water-soluble owing to the formation of carbamate groups. This water-soluble silver nanoparticle presents an exceptional performance in the selective reduction of 4-nitrophenol, where the turnover frequency (TOF = 599 h −1 ) is even double with respect to the CO 2 free system.
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高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2016
·
IF 2.76
Zhan-Chao Wu,Zhao-Zhan Wang,Jie Liu,Jin-Hua Yin,Shao-Ping Kuang
A new adsorbent l -Arg-CS/Fe 3 O 4 was prepared by l -arginine modifying magnetic chitosan for the removal of Cu(II ) ions from aqueous solution. The compositions of l -Arg-CS/Fe 3 O 4 were characterized by infrared (IR) spectroscopy, X-ray diffraction (XRD) analysis and thermogravimetric (TG) analysis, respectively. The surface morphology, particle size and specific surface area were measured on scanning electron microscope (SEM) and micromeritics gas adsorption surface analyzer. The adsorption behavior of l -Arg-CS/Fe 3 O 4 for Cu(II ) were investigated as a function of pH, contact time and initial Cu(II ) concentration. The maximum adsorption capacity for Cu(II ) was 2.13 mmol g −1 at the optimized adsorption conditions, which were pH = 5.5, t = 13 min, C 0 = 4.0 mmol L −1 . The adsorption behavior was evaluated by the analysis of adsorption kinetics. Freundlich and Langmuir isotherm models were used to estimate the adsorption mode. l -Arg-CS/Fe 3 O 4 exhibited high adsorption capability after five regeneration cycles. The adsorption and desorption mechanisms were discussed. The results show that l -Arg-CS/Fe 3 O 4 is a promising adsorbent for removal of Cu(II) from aqueous solutions.
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高影响因子
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