CARBOHYDRATE POLYMERS
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2020
·
IF 7.182
Yucheng Zou,Cen Zhang,Peng Wang,Yipeng Zhang,Hui Zhang
The aim of this study was to develop chitosan (CS)/polycaprolactone (PCL) electrospun nanofibers with chlorogenic acid (CGA) loaded halloysite nanotubes (HNTs) as a carrier for CGA to provide a long-term sustained release. Results showed that the addition of [email protected] at the concentrations of 2–6 wt% resulted in continuous nanofibers with an average diameter range of 159–166 nm, with improved thermal stability caused by the formation of hydrogen bonds. The incorporation of [email protected] induced a hydrophilic surface and enhanced water vapor barrier property, but impaired the mechanical properties. However, the 2%, 4%, and 6% [email protected] incorporated fibrous mats exhibited an initial release of 18.3 %, 26.2 %, 33.1 % within 15 h, and 34.7 %, 41.4 %, 51.3 % release after 240 h, respectively, indicating a long-term sustained release with enhanced antioxidant and antimicrobial activities. These results suggested the promising applications of the prepared [email protected] /PCL/CS electrospun fibrous mats for active food packaging.
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高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Jiayi Zhao,Feng Wei,Weili Xu,Xiaojun Han
The high demand for food safety and quality has stimulated the investigation of antibacterial packaging films based on natural biomaterials. Capsaicin, an effective extract of red chili, is thought to be a favorable antibacterial candidate in food packaging. Herein, Fe III doped hollow metal-organic frameworks (Fe III -HMOF-5) were prepared as promising nanocarriers for capsaicin and incorporated into gelatin/chitosan matrix to fabricate antibacterial packaging films. Fe III -HMOF-5 regulated the hydrophobicity of capsaicin and effectively solved the phase separation problem. The addition of capsaicin loaded Fe III -HMOF-5 into gelatin/chitosan film significantly improved the tensile strength, water vapor permeability and UV barrier properties. Moreover, Cap-Fe III -HMOF-5 endowed efficient antimicrobial activity against E. coli to gelatin/chitosan films by practical application on fresh apple cubes . The strategy proposed here provides an effective way to develop promising antibacterial biomaterials for food packaging.
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INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
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2021
·Vol. 22
·期 14
·7610
·
IF 5.924
Zhenyu Chen,Xiaoning Zhang,Jianwei Liang,Yansong Ji,Yuqing Zhou,Hao Fang
At present, silk fibroin (SF) hydrogel can be prepared by means of electrodeposition at 25 V in direct current (DC) mode. Reducing the applied voltage would provide benefits, including lower fabrication costs, less risk of high voltage shocks, and better stability of devices. Here, a simple but uncommon strategy for SF-based hydrogel preparation using 4 V in DC mode is discussed. SF was mixed and cross-linked with carboxymethyl chitosan (CMCS) through hydrogen bonding, then co-deposited on the graphite electrode. The thickness, mass, and shape of the SF/CMCS hydrogel were easily controlled by adjusting the electrodeposition parameters. Morphological characterization of the prepared hydrogel via SEM revealed a porous network within the fabricated hydrogel. This structure was due to intermolecular hydrogen bonding between SF and CMCS, according to the results of thermogravimetric analysis and rheological measurements. As a potential wound dressing, SF/CMCS hydrogel maintained a suitable moisture environment for wound healing and demonstrated distinct properties in terms of promoting the proliferation of HEK-293 cells and antibacterial activity againstEscherichia coliandStaphylococcus aureus. Furthermore, histological studies were conducted on a full-thickness skin wound in rats covered with the SF/CMCS hydrogel, with results indicating that this hydrogel can promote wound re-epithelization and enhance granulation tissue formation. These results illustrate the feasibility of using the developed strategy for SF-based hydrogel fabrication in practice for wound dressing.Keywords:silk fibroin;carboxymethyl chitosan;electrodeposition;wound dressing
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JOURNAL OF MEMBRANE SCIENCE
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2021
·
IF 8.742
Min Hu,Lina Zhao,Ningbo Yu,Ziqi Tian,Zhonglong Yin,Zhen Yang,Weiben Yang,Nigel J.D. Graham
Membrane fouling is a major obstacle for ultrafiltration (UF) in water treatment. Here, a strategy for fouling mitigation, by applying an ultra-low concentration of moderately-hydrophobic chitosan (MHC) and using a mildly elevated backwash temperature was proposed. The effects of MHC type, concentration, and backwash temperature were investigated in continuous-flow tests using PVDF hollow fiber membranes and model raw water. Compared to the process without MHC, or with the addition of chitosan or conventional coagulant polyaluminum chloride, the MHC-based UF system under optimal conditions (MHC: 0.01 mg/L; backwash water temperature: 40 °C) demonstrated its superiority with reduction of ~55% reversible fouling ( RR ) and ~80% irreversible fouling ( IRR ), as well as improved effluent quality. A mechanistic study by experimental analyses and theoretical computations revealed that the improved performance of the MHC-based UF process was attributed to the following: (1) MHC inhibited contaminant accumulation on the membrane through a hydrophilization surface-modification effect on the PVDF; (2) increased backwash temperature promoted fouling release (by destabilizing the cake layer structure) and enhanced the surface-modification effect. The additional cost of MHC dosing and backwash water heating was estimated at ~0.126 Chinese Yuan per ton of produced water, and the environmental risk of applying MHC was lower than that of conventional water treatment chemicals . In summary, the MHC-based process has the potential to be a feasible and cost-effective approach for UF fouling control.
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IONICS
·
2021
·Vol. 27
·期 9
·3975-3985
·
IF 2.817
Wang Zhiyi,Wang Yutian,Tang Jingtao,Wang Kaizhao,Chen Tianyou,Wang Kaijun,Hu Jin
Among the currently studied nitrogen-doped Pt-C catalysts, the environmental friendliness of the nitrogen source and the stability of Pt-C catalysts for fuel cells are urgent issues to be solved. In this study, nitrogen-doped platinum-based catalyst (CSC/BP-Pt) with excellent stability for the ORR is prepared by a self-doping method based on chitosan (CS), a green biomass material with both nitrogen and carbon sources, in combination with conductive carbon black (BP2000). Finally, the N content of the catalyst is as high as 5.8 wt%, which is higher than most comparable catalysts (3–5 wt%). And electrochemical tests show that the CSC/BP-Pt electrochemical active surface area (ECSA) = 154.1 m 2 /g Pt , half-wave potential (E 1/2 = 0.85 V RHE ) has a better electrochemical performance than the commercial Pt/C (20 wt%), while the half-wave potential is reduced at 10,000 cycles of cyclic voltammetry with almost no attenuation (only 7 mVcompared to 31 mV of Pt/C). Besides, possible mechanisms to improve the activity and stability of CSC/BP-Pt are preliminarily proposed.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2021
·Vol. 139
·期 1
·51425
·
IF 3.125
Qingyuan Chen,Zhongbin Ye,Hongwei Xu,Yuqi Wang,Nanjun Lai
This study introduced a chitosan-modified hyperbranched polymer (HPDACS). The biological oxygen demand, chemical oxygen demand, and biodegradability of HPDACS under different water quality were measured under static conditions, as well as the concentration changes before and after degradation. Environmental scanning electron microscopy (ESEM) was used to observe the micromorphology before and after degradation. The biodegradability, viscosity change, and molecular weight change of the polymer before and after passing through the porous medium were measured. The results were compared with the partially hydrolyzed polyacrylamide and the dendritic polymer. The results showed that in bacteria-containing sewage, the biodegradation rate of HPDACS reached 81%. Moreover, the molecular backbone of HPDACS was completely broken after degradation. Its viscosity loss reached 84.87%, indicating its good biodegradability. HPDACS also can reduce the concentration of polymer in the produced fluid. In core flow experiments, viscosity of HPDACS is loss to 40%. The hyperbranched network structure of HPDACS can reduce the shearing action in the porous medium, thus reducing the extent of biodegradation. The presence of microorganisms resulted in a viscosity loss of HPDACS of ~2%. Therefore, HPDACS can fully exert the fluidity control effect through the porous medium and can meet the requirements of polymer flooding.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 139
·期 10
·51742
·
IF 3.125
Danning Gao,Qi Zhang,Zhifeng Liu,Fureng Zhang,Faliang Gou,Guiying Xing,Shujing Zhou,Linjun Shao,Jinjing Li,Yijun Du,Chenze Qi
We report the synthesis of palladium nanoparticles encapsulated N-doped carbon nanofibers derived from environmentally benign chitosan. Palladium salt was incorporated into the chitosan/sodium polyacrylate composite nanofibers by electrospinning, followed by carbonization under argon atmosphere to prepare palladium encapsulated mesoporous carbon nanofibers (Pd@Carbon). SEM images shows that the fibrous structures were well retained after carbonization processes. The Raman spectra demonstrates that the ratio of graphite carbon were increased with the carbonization temperature. X-ray powder diffraction and transmission electron microscopy analysis shows that PdO and Pd nanoparticles were formed in the carbon fibers and their sizes grew with the carbonization temperature. The sizes and concentrations of submicroscopic pores inside the nanofibers were analyzed by nitrogen adsorption/desorption experiments and positron annihilation lifetime spectra. Heck reaction catalysis result shows that high carbonization temperature could improve the catalytic activity of Pd@Carbon nanofibers and the nanofibers carbonized at 800°C had the highest catalytic activity. Moreover, the catalytic activity of these novel composite nanofibers was well retained even after recycling for 13 times. The excellent catalytic performance of this fibrous palladium catalyst can be attributed to the N-rich carbon nanofibers and encapsulation of palladium active species inside the ultrathin mesoporous carbon fibers.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Dalin Hu,Zhenwei Lian,Hongyi Xian,Ran Jiang,Nan Wang,Yingying Weng,Xiaowu Peng,Sanming Wang,Xiao–Kun Ouyang
A creative combination of chitosan with polyacrylic acid (PAA) improves the acidity resistance of chitosan and increases its potential in the field of adsorption. In order to facilitate recovery, magnetic nanoparticles were incorporated in CS–PAA to obtain a magnetic-CS–PAA (MCS–PAA) nanocomposite. The physical and chemical characteristics of the composite adsorbent MCS–PAA were determined by SEM, TEM, FTIR, EDX , XRD, and XPS. This environmental-friendly, magnetic, composite adsorbent showed significantly better adsorption performance than those of the individual adsorbents alone. The maximal adsorption capacity was 204.89 mg/g according to the Langmuir isotherm model, when the concentration of Pb(II) was 100 mg/L at the equilibrium time of 70 min. The main adsorption mechanism was the complexation between the carboxyl, amino, and hydroxyl groups in MCS–PAA and Pb(II). Further, introduction of PAA also improved the acid resistance of CS. The new adsorbent MCS–PAA is thus expected to facilitate a wider range of applications for chitosan in the adsorption of Pb(II).
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JOURNAL OF NANOBIOTECHNOLOGY
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2019
·Vol. 17
·期 1
·1-18
·
IF 5.345
Niu Shiwei,Williams Gareth R.,Wu Jianrong,Wu Junzi,Zhang Xuejing,Chen Xia,Li Shude,Jiao Jianlin,Zhu Li-Min
Background It is extremely difficult to develop targeted treatments for triple-negative breast (TNB) cancer, because these cells do not express any of the key biomarkers usually exploited for this goal.Results In this work, we develop a solution in the form of a cascade responsive nanoplatform based on thermo-sensitive poly(N-vinylcaprolactam) (PNVCL)-chitosan (CS) nanoparticles (NPs). These are further modified with the cell penetrating peptide (CPP) and loaded with the chemotherapeutic drug doxorubicin (DOX). The base copolymer was optimized to undergo a phase change at the elevated temperatures of the tumor microenvironment. The acid-responsive properties of CS provide a second trigger for drug release, and the inclusion of CPP should ensure the formulations accumulate in cancerous tissue. The resultant CPP-CS-co-PNVCL NPs could self-assemble in aqueous media into spherical NPs of size < 200 nm and with low polydispersity. They are able to accommodate a high DOX loading (14.8% w/w). The NPs are found to be selectively taken up by cancerous cells both in vitro and in vivo, and result in less off-target cytotoxicity than treatment with DOX alone. In vivo experiments employing a TNB xenograft mouse model demonstrated a significant reduction in tumor volume and prolonging of life span, with no obvious systemic toxicity.Conclusion sThe system developed in this work has the potential to provide new therapies for hard-to-treat cancers.
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PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
·
2019
·Vol. 216
·期 22
·1900379
·
IF 1.606
Liang Ma,Xuejuan Shi,Xiaoxiao Zhang,Shunjun Dong,Lili Li
Core–shell-structured cellulose acetate–polycaprolactone/chitosan (CA–PCL/CS) nanofibers with excellent removal performance of hexavalent chromium (Cr(VI)) are developed by coaxial electrospinning. The effect of core-to-shell ratio on adsorption capability is studied. The results show that all core–shell-structured fibers possess higher adsorption capability and good durability in acidic environment compared with the CS powder adsorbent. CA–PCL/CS fibers with core-to-shell ratio of 0.442 have a maximum adsorption capability of 126 mg g −1 at room temperature. The adsorption kinetics reveals that chemisorption serves as the rate-determining step by notable electron transfer, share, or exchange between adsorbents and adsorbates. The adsorption equilibrium data of the core–shell-structured CA–PCL/CS fiber adsorbents are all well described by the Freundlich isotherm model, indicating the multilayer adsorption process. Herein, it is highlighted that the core–shell-structured CA–PCL/CS nanofibers have a promising prospect in removing Cr(VI) ions from waste water.
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Marine Drugs
·
2019
·Vol. 17
·期 10
·575
·
IF 3.772
Yingjun Gao,Xing Zhang,Xiangyu Jin
As derivatives from marine natural biomaterials, alginate-based and chitosan-based biomaterials are commonly used in wound dressings. Calcium alginate fiber (CAF) dressings possess excellent absorption and unique gel forming performance, but the low bioactivity limits its application in wound healing. Carboxymethyl chitosan (CM-Chit) has excellent antibacterial activity, but the gel structure with weak mechanical properties restricts its application. In this study, minocycline (Mino)/CM-Chit solution was coated on the surface of plasma treated CAF needle-punched nonwovens, and then Mino loaded CM-Chit gel/CAF nonwovens composite dressings were fabricated by EDC/NHS (1-3-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide) crosslinking. The dressings had a porous composite structure, which allowed them to quickly absorb and store a large number of wound exudates. Skin-like tensile performance allowed the dressings to provide a better healing environment. Antibacterial assay againstEscherichia coliandStaphylococcus aureusindicated that the addition of Mino significantly improved the antibacterial activity of the wound dressings. The tight structure of CM-Chit gel prevented the burst release of Mino so that the dressings had antibacterial activity in a certain period of release time. Cell culture assay showed that the dressings had excellent cell biocompatibility. As new functional dressings, the prepared composite dressings had excellent potential in the clinical healing of wounds.Keywords:alginate fibers;carboxymethyl chitosan;wound dressings;antibacterial activity;drug release
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2019
·Vol. 191
·期 2
·605-622
·
IF 2.14
Bai Rubing,Yu Yuanyuan,Wang Qiang,Shen Jinsong,Yuan Jiugang,Fan Xuerong
Chitosan oligosaccharide (COS), a water-soluble carbohydrate obtained from chemical or enzymatic hydrolysis of chitosan, has similar structure and properties to non-toxic, biocompatible, and biodegradable chitosan. However, COS has many advantages over chitosan due to its low molecular weight and high water solubility. In the current work, COS was incorporated in the laccase-catalyzed polymerization of hydroquinone. The laccase-catalyzed polymerization of hydroquinone with or without COS was investigated by using simple structure of glucosamine hydrochloride as an alternative to COS to understand the mechanism of COS-incorporated polymerization of hydroquinone. Although polyhydroquinone can be regarded as the polymeric colorant with dark brown color, there is no affinity or chemical bonding between polyhydroquinone and cotton fibers. Cotton fabrics were successfully in-situ dyed into brown color through the laccase-catalyzed polymerization of hydroquinone by incorporating with COS as a template. The presence of COS enhanced the dye uptake of polyhydroquinone on cotton fibers due to high affinity of COS to cotton and covalent bonding between COS and polyhydroquinone during laccase catalysis. This novel approach not only provides a simple route for the biological coloration of cotton fabrics but also presents a significant way to prepare functional textiles with antibacterial property.
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