POLYMER
·
2015
·
IF 3.562
Linjun Shao,Yuan Ren,Zining Wang,Chenze Qi,Yao Lin
Using electrospinning technique to prepare chitosan (CS) nanofibers from an inexpensive solvent such as acetic acid has been a challenge, due to the lack of sufficient entanglements in these semi-rigid polyelectrolytes . Incorporating polymers such as poly(methacrylic acid) (PMAA) into the solution lowers the entanglement concentration of the polymers, and make all three morphology regimes (polymer droplets, beaded nanofibers and nanofibers with uniform thickness) accessible to electrospinning method. Uniform composite nanofibers are found at concentrations well above the entanglement concentration. The thickness and morphology of nanofibers can be regulated by addition of small amount of organic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The composite nanofibers are subsequently crosslinked at an elevated temperature to improve their thermal and solvent stability. The mechanical properties of the crosslinked CS/PMAA fibers can be modulated by varying the amount and molecular weight of PMAA incorporated in the blend. The composite fiber materials provide a useful platform to support a variety of catalysts. As a demonstration, palladium catalyst has been immobilized on the crosslinked CS/PMAA nanofibers to carry out Mizoroki–Heck cross-coupling reactions of aromatic halides and acrylates . We found remarkable catalytic efficiency and stability in these materials. We also demonstrate that, by the “post-modification” of the nanofibers with ligands that chelate metal catalysts , a variety of metal catalysts can be incorporated into the fiber platform, with further improved stability and activity.
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APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Heqing Fu,Yin Wang,Weifeng Chen,Jing Xiao
Waterborne polyurethane/halloysite nanotubes nanocomposites were prepared by modified halloysite nanotubes (HTs) with chitosan (CS). Modified HTs were characterized by Fourier transform infrared spectroscopy, elemental analysis, and thermogravimetry, which verified that CS was successfully assembled onto the HTs surface. The chitosan-modified halloysite nanotubes (CHTs) were uniformly dispersed in WPU matrix through the reaction with polyurethane prepolymer, and acted as chain cross-linker as well as reinforcing filler, which increased the cross-linking density of nanocomposites. The experimental results showed that the strong interfacial interaction and hydrogen bonding interaction between CHTs and WPU improved the degree of micro-phase separation, thermal properties, mechanical properties and surface properties of nanocomposites. The tensile strength and elongation at break were simultaneously enhanced when the CHTs loading was below 2 wt%.
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COLLOIDS AND SURFACES B-BIOINTERFACES
·
2014
·
IF 4.287
Fang Yuan,Shasha Wang,Gaojian Chen,Kehua Tu,Hongliang Jiang,Li-Qun Wang
A novel approach to design pH-sensitive and disintegrable polyelectrolyte nanogels composed of citraconic-based N -(carboxyacyl) chitosan (polyanion) and quaternary chitosan (polycation) was reported. Firstly, the hydrolysis of citraconic-modified chitosan was monitored using fluorescamine assay and it could selectively dissociate in acidic media (e.g., pH ∼5.0) due to the isomerization during the addition of citraconic anhydride to chitosan. Secondly, the self-assembly behaviors of different polyelectrolyte pairs between citraconic-based chitosan and quaternary chitosan were investigated via colloidal titration assay. It was indicated that the difference in molecular weight (MW) of opposite charged polyelectrolytes played an important role on the formation of polyelectrolyte nanogels. Results showed that polyelectrolyte nanogels (ca. 300 nm in size) only formed when polyanion and polycation had a very large difference in MW. The pH-sensitive behavior of polyelectrolyte nanogels was comprehensively investigated by dynamic light scattering (DLS) and transmission electron microscope (TEM). The incorporation of charge-conversional citraconic-based chitosan into polyelectrolyte complexes has provided an effective approach to prepare polyelectrolyte nanogels which were very stable at neutral pH but disintegrated quickly in acidic media.
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BIORESOURCE TECHNOLOGY
·
2014
·
IF 5.039
Changlong Dong,Wei Chen,Cheng Liu
A kind of amphoteric chitosan-based flocculant (quaternized carboxymethyl chitosan, denoted as QCMC) has been prepared. QCMC presented significant improvement of water solubility in the whole pH range. The effects of pH, dosage, temperature and original turbidity of algal water on the flocculation performance were investigated. The optimal dosages of QCMC at pH 5, 9 and 12 with original turbidity of 20 NTU at 20 °C were 0.1, 0.6 and 2.0 mg/L, respectively, which were much less than that of chitosan, PAM, Al 2 (SO 4 ) 3 and FeCl 3 . The floc properties during grow, breakage and regrow period were also evaluated at different pH values in terms of floc size, strength and density. It was demonstrated that QCMC produced larger, stronger and denser flocs than Al 2 (SO 4 ) 3 . There is every indication that QCMC is more suitable for algal harvesting than other traditional coagulants or flocculants.
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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2017
·Vol. 17
·期 6
·3873-3879
·
IF 1.483
Hu Gaoli,Song Botao,Zhu Jie
The aim of this study was to implement a novel bioinspired process based on the superhydrophobic surface to produce organic solvent-free spheres for drug controlled release. Firstly, superhydrophobic substrate with large area was successfully constructed in one step by the electrospray
approach. Then, by utilizing the as-synthesized superhydrophobic substrate the chitosan (CS) spheres with controllable sizes and drug loading contents were fabricated. The drug encapsulation efficiency was further carefully studied, and it was found that the encapsulation efficiencies were
very high and could reach up to 92% and above. Finally, the drug release behaviors of the drug-loaded CS spheres were systematically investigated, and the results demonstrated that both the diameter of the CS spheres and the drug loading content influenced the drug release characteristics.
This present approach opened up a new possibility for the development of novel drug delivery systems with controllable drug delivery property for a broad range of pharmaceutical and biomedical applications.
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Polymers
·
2017
·Vol. 9
·期 4
·116
·
IF 3.364
Rengui Weng,Lihui Chen,Shan Lin,Hui Zhang,Hui Wu,Kai Liu,Shilin Cao,Liulian Huang
Presently, most nanofiltration membranes are prepared with non-biodegradable petrochemical materials. This process is harmful to the ecosystem and consumes a large amount of non-renewable energy. In this study, biodegradable and biocompatible antibacterial cellulose/chitosan nanofiltration membranes (BC/CS-NFMs) were fabricated and characterized for their mechanical strength, antimicrobial activity, salt and dye filtration performance, and polyethylene glycol (PEG) retention using Thermal gravimetric analysis (TGA), Field emission scanning electron microscopy(FE-SEM), Fourier transform infrared spectroscopy(FT-IR), and X-ray diffraction (XRD). The BC/CS-NFMs were obtained by the hydrolysis and carboxymethylation of dense cellulose/chitosan membranes (BC/CSMs). The tensile strength of the BC/CS-NFMs decreased as the chitosan content increased. In addition, the thermal stability and antibacterial ability of the BC/CS-NFMs improved. The pore size is less than 1 nm, and a spongy, layered structure is observed in the cross-sectional FE-SEM images. FT-IR analysis shows that a part of the hydroxyl in cellulose transforms to carboxymethyl during the hydrolysis and carboxymethylation of the BC/CSMs. No obvious changes can be observed in the cellulose and chitosan after the blend membrane formation from the XRD measurements. Based on the experimental results on the permeation and rejection of BC/CS-NFMs, different proportions of cellulose and chitosan nanofiltration membranes almost did not affect the water flux and rejection rate. The BC/CS-NFMs showed better water flux and a higher rejection rate in aqueous dye-salt solutions.Keywords:cellulose;chitosan;antibacterial activity;nanofiltration membranes
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Analytical Methods
·
2024
·
IF 2.7
Junwei Yang,Si Zhou,Haijiao Zheng,Qiong Jia
One of the most crucial and prevalent post-translational modifications is the phosphorylation of proteins. The study and examination of protein phosphorylation hold immense importance in comprehending disease mechanisms and discovering novel biomarkers. However, the inherent low abundance, low ionization efficiency, and coexistence with non phosphopeptides seriously affect the direct analysis of phosphopeptides by mass spectrometry. In order to tackle these problems, it is necessary to carry out selective enrichment of phosphopeptides prior to conducting mass spectrometry analysis. Herein, magnetic chitosan nanoparticles were developed by incorporating arginine, and were then utilized for phosphopeptide enrichment. A tryptic digest of β-casein was chosen as the standard substance. After enrichment, combined with matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS), the detection limit of the method was 0.4 fmol. The synthesized magnetic material demonstrated great potential in the detection of phosphopeptides in complex samples, as proven by its successful application in detecting phosphopeptides in skim milk and human saliva samples.
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Biomedical Materials
·
2024
·Vol. 19
·期 4
·045042
·
IF 3.9
Ling Wang,Xiaoyue Ding,Jingyu Li,Man Li,Peng Ding,Wei Guo,Qiaoyun Wu,Yanfang Sun,Guohua Jiang,Oseweuba Valentine Okoro,Mahta Mirzaei,Amin Shavandi,Lihong Fan,Lei Nie
Bacterial infection can lead to various complications, such as inflammations on surrounding tissues, which can prolong wound healing and thus represent a significant clinical and public healthcare problem. Herein, a report on the fabrication of a novel genipin/quaternized chitosan (CS) hydrogel for wound dressing is presented. The hydrogel was prepared by mixing quaternized CS and genipin under 35 °C bath. The hydrogels showed porous structure (250–500 μm) and mechanical properties (3000–6000 Pa). In addition, the hydrogels displayed self-healing ability and adhesion performance on different substrates. Genipin crosslinked quaternized CS hydrogels showed antibacterial activities against E. coli and S. aureus. The CCK-8 and fluorescent images confirmed the cytocompatibility of hydrogels by seeding with NIH-3T3 cells. The present study showed that the prepared hydrogel has the potential to be used as wound dressing.
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RSC Advances
·
2011
·Vol. 1
·期 2
·282-289
·
IF 0
Xueying Qiu,Yuhong Yang,Liping Wang,Shanling Lu,Zhengzhong Shao,Xin Chen
Time-evolved gelation behavior of a chitosan-β-glycerophosphate (CS/β-GP) system was elucidated from rheological investigation, NMR analysis, fluorescence measurement, and morphology observation. Urea and isobutanol were selected to assess the interactions between the two components during the gelation process of the CS/β-GP system. Urea was found to be detrimental to the gelation process by both disrupting hydrogen bonding and retarding the formation of hydrophobic domains. On the contrary, the addition of isobutanol accelerated the sol–gel transition by strengthening the hydrophobic interactions. These results reveal that both hydrogen bonding and hydrophobic interactions within chitosan or between chitosan and β-glycerophosphate molecules are the main reasons for gel formation. The results also indicate that firstly the formation of hydrogen bonds makes the hydrophobic sites more accessible, and then the synergistic hydrogen bonding and hydrophobic interactions lead to the final formation of CS/β-GP gel network. This work demonstrates the possibility of tuning the gelling ability as well as the mechanical properties of CS/β-GP hydrogels. Thus, it gives the opportunities to optimize the performance of this promising natural thermosensitive material for practical applications in the future.
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Advanced Healthcare Materials
·
2024
·
IF 10
Jiaying Zhang,Sifang Zhao,Yifan Zhou,Hongze Liang,Lingling Zhao,Hui Tan
Diabetic wound healing is hampered due to oxidative stress, exacerbated inflammation, and impaired angiogenesis in the wounds. A pH-sensitive antioxidant hydrogel based on carboxymethyl chitosan (CMCS), oligoprocyanidins (OPC), and oxide dextran (Oxd) is prepared to accelerate diabetic wound healing. The hydrogel network is formed via imine and hydrogen bonding interactions in the presence of hydroxyl, amino, and aldehyde groups, and deferoxamine (DFO) is incorporated into the hydrogel. The hydrogel shows pH-triggered drug release, a good antioxidant, and anti-inflammatory properties, and can promote tube formation and cell migration in vitro. Moreover, the hydrogel can accelerate wound healing in streptozotocin (STZ)-induced diabetic mice by regulating the inflammation environment with up-regulation of anti-inflammatory factors (IL-4 and IL-10) and down-regulation of pro-inflammatory factors (TNF-α and IL-6), and promoting angiogenesis with up-regulation of HIF-1α, VEGF, and CD31. Thus, the pH-sensitive antioxidant hydrogel provides a promising therapeutic strategy for diabetic wound healing.
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ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Wen Tang,Huiwen Hou,Hanlin Wang,Xinqing Gao,Feiyan Zhao,Yuhan Di,Shengli Ji,Peixue Ling,Fengshan Wang,Feng Sun,Haining Tan
Cancer presents a significant health threat, necessitating the development of more precise, efficient, and less damaging treatment approaches. To address this challenge, we employed the 1-ethyl-(3-dimethyl aminopropyl) carbodiimide/N-hydroxy succinimide (EDC/NHS) catalytic system and utilized quaternized chitosan oligosaccharide (HTCOSC) as a drug carrier to construct a nanoparticle delivery system termed HTCOSC-cRGD-ES2-MTX (CREM). This system specifically targets integrin αvβ3 on tumor cell surfaces and enables simultaneous loading of the antiangiogenic agent ES2 (IVRRADRAAVP) and the chemotherapy drug methotrexate (MTX). Due to its amphiphilic properties, CREM self-assembles into nanoparticles in aqueous solution, exhibiting an average diameter of 179.47 nm. Comparative studies demonstrated that CREM, in contrast to free ES2 and MTX-free nanoparticles (CRE), significantly suppressed the proliferation of EAhy926 endothelial cells and B16 melanoma cells in vitro, resulting in inhibition rates of 71.18 and 82.25%, respectively. Furthermore, CREM exhibited a hemolysis rate below 2%, indicating excellent in vitro antiangiogenic and antitumor activity as well as favorable blood compatibility. Additionally, both CRE and CREM demonstrated favorable tumor targeting capabilities through the specific binding action of cyclic RGD (cRGD) to integrin αvβ3. Further in vivo investigations revealed that CREM induced apoptosis in tumor cells via the mitochondrial apoptotic pathway and reduced the expression of angiogenic factors such as vascular endothelial growth factor (VEGF), thereby inhibiting tumor angiogenesis. This potent antitumor effect was evident through a tumor suppression rate of 80.19%. Importantly, histopathological staining (HE staining) demonstrated the absence of significant toxic side effects of CREM on various organs compared to MTX. In conclusion, the CREM nano drug delivery system synergistically enhances the therapeutic efficacy of antiangiogenic drugs and chemotherapeutic agents, thus offering a novel targeted approach for cancer treatment.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Yanan Huang,Xiaotong Wang,Bodan Luo,Peng Jin,Yonghua Zheng,Changliang Xu,Zhengguo Wu
Effective control of wound bleeding and sustained promotion of wound healing remain a major challenge for hemostatic materials. In this study, the hemostatic sponge with controllable antibacterial and adjustable continuous promotion of wound healing (CMN Cu) was prepared by chitosan, aminated MXene and copper ion . Interestingly, the internal topological point-line-surface interaction endowed the CMN-Cu sponge longitudinal staggered tubular porous microstructure, combined with the lipophilic properties obtained by modified MXene, which greatly improved its flexibility, wet elasticity and blood enrichment capacity. In addition, the sponge achieved controlled release of active ingredients, which made it present highly effective antibacterial activity and long-lasting ability to promote wound healing. In vitro and in vivo experiments confirmed that CMN-Cu sponge presented high-efficient hemostatic performance. Last but not least, a series of cell experiments showed that the CMN-Cu sponge had excellent safety as a hemostatic material.
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