查找使用阿拉丁产品的科研文献

Chitosan coated fluorescent mesoporous silica for the sensitive and selective detection of H2O2

Xinhui Hou,Yifan Song,Hengquan Zhou,Lei Guo,Guiying Li,Qian Tao

A novel turn-on fluorescent sensor for hydrogen peroxide (H 2 O 2 ) was prepared from chitosan (CS) coating mesoporous silica nanoparticles (MSNs) loaded with 1-(4-Aminophenyl)-1,2,2-triphenylethene (TPE-NH 2 ) and silver nanoparticles (AgNCs). The surface of MSNs was coated by CS as the gatekeeper and the template for loading of AgNCs. Because of the surface plasmon-enhanced energy transfer (SPEET), AgNCs effectively quenched the fluorescence emission of nanoparticles. In the presence of H 2 O 2 , AgNCs can be oxidized to Ag + , resulting in the recovery of fluorescence. This fluorescent sensor was characterized with respect to its chemical composition, morphological features and optical properties by means of FTIR, XRD, TGA, SEM, TEM, XPS, UV–Vis and fluorescence spectroscopy. The MSN/TPE-CS@Ag nanoparticles showed good sensitivity and selectivity for H 2 O 2 even with various interfering ions and agents. Under optimized conditions, the detection limit for H 2 O 2 was 0.64 μM in the rage of 1–300 μM. The feasibility of the practical application of this probe was confirmed by accurate quantitative of H 2 O 2 in practical samples.

Accurate Determination of the Degree of Deacetylation of Chitosan Using UPLC–MS/MS

Ting Xue,Wenqing Wang,Zhiyuan Yang,Fanjun Wang,Lei Yang,Jian Li,Hui Gan,Ruolan Gu,Zhuona Wu,Guifang Dou,Zhiyun Meng

The mole fraction of deacetylated monomeric units in chitosan (CS) molecules is referred to as CS’s degree of deacetylation (DD). In this study, 35 characteristic ions of CS were detected using liquid chromatography–electrospray ionization–mass spectrometry (LC–ESI–MS/MS). The relative response intensity of 35 characteristic ion pairs using a single charge in nine CS samples with varying DDs was analyzed using 30 analytical methods. There was a good linear relationship between the relative response intensity of the characteristic ion pairs determined using ultrahigh performance (UP) LC–MS/MS and the DD of CS. The UPLC–MS/MS method for determining the DD of CS was unaffected by the sample concentration. The detection instrument has a wide range of application parameters with different voltages, high temperatures, and gas flow conditions. This study established a detection method for the DD of CS with high sensitivity, fast analysis, accuracy, stability, and durability.Keywords:chitosan;degree of deacetylation determination;UPLC–MS/MS;relative response intensity of the characteristic peak

A dual-function chitosan packaging film for simultaneously monitoring and maintaining pork freshness

Wanmei Lin,Gengli Huang,Weixia Yang,Shuhao Zeng,Xueli Luo,Jihong Huang,Zhonghong Li

Exploring food packaging films simultaneously possess freshness monitoring and maintaining can effectively tackle food safety issues. Here, we constructed a chitosan/N-doped carbon dots (CS/N-CDs) film which can monitor the freshness of pork based on pH-mediated fluorescent sensing and extend the shelf life based on the antioxidant, antibacterial and UV shielding properties. The fluorescent intensity of CS/N-CDs films increased with the increase of pork pH from 5.77 to 6.84 which positively related to the change of TVB-N from 6.68 to 17.53 mg/100 g. CS/N-CDs films had a maintaining effect on pork freshness corroborated by the scavenging activity on DPPH and ABTS radicals and antibacterial efficiency and inhibition zones of S. aureus and E.coli , and the total viable count, a value, weight loss, hardness and springiness of pork. Cell viability and hemolytic activity assay proved that CS/N-CDs films was safe. A novel chitosan-based intelligent and active food packaging film was provided.

Preparation of Chitosan/Recombinant Human Collagen-Based Photo-Responsive Bioinks for 3D Bioprinting

Yang Yang,Zixun Wang,Yuanyuan Xu,Jingjing Xia,Zhaoxian Xu,Shuai Zhu,Mingjie Jin

Collagen and chitosan are frequently used natural biomaterials in tissue engineering. However, most collagen is derived from animal tissue, with inconsistent quality and pathogen transmittance risks. In this context, we aimed to use a reliable Type-III recombinant human collagen (RHC) as an alternative biomaterial together with chitosan to develop novel photo-responsive bioinks for three-dimensional (3D) bioprinting. RHC was modified with methacrylic anhydride to obtain the RHC methacryloyl (RHCMA) and mixed with acidified chitosan (CS) to form composites CS-RHCMA. The characterizations demonstrated that the mechanical properties and the degradation of the bioinks were tunable by introducing the CS. The printabilities improved by adding CS to RHCMA, and various structures were constructed via extrusion-based 3D printing successfully. Moreover, in vitro tests confirmed that these CS-RHCMA bioinks were biocompatible as human umbilical vein endothelial cells (HUVECs) were sustained within the constructs post-printing. The results from the current study illustrated a well-established bioinks system with the potential to construct different tissues through 3D bioprinting.Keywords:chitosan;recombinant human collagen;bioinks;3D printing;tissue engineering

Recovering copper ions from wastewater with chitosan to synthesize lead-free primary explosives

Xuwen Liu,Yan Hu,Caimin Yang,Jiaxin Su,Yinghua Ye,Ruiqi Shen

Chitosan (CTS) is a well-known adsorbent capable of absorbing copper ions . It's also a high-quality biomass carbon source. The carbon skeleton formed by the pyrolysis of CTS has outstanding electrical conductivity , which can help copper azide (CA), a new type of primary explosive that's particularly sensitive to electrostatic stimuli, be more electrostatically safe. The CTS-Cu complex is precipitated by using CTS to adsorb and flocculate copper ions in wastewater. To construct the Cu@carbonized chitosan (CCTS) precursor material, the organic ligands in the CTS-Cu complex are calcined into a porous three-dimensional carbon matrix, and the copper ions are transformed into copper nanoparticles embedded in CCTS. The azide reaction converts copper nanoparticles (CuNPs) into high-energy CA. With its good electrical conductivity, CCTS maintains its framework structure and effectively improves the electrostatic safety of composite energetic materials. CA@CCTS has a CA content of 69.7%, an electrostatic ignition energy (E 50 ) of about 1.19 mJ, and a heat release of 1803.22 J/g. This work takes advantage of CA and CTS's environmental friendliness. CA@CCTS, as a novel lead-free primary explosive, has good electrostatic safety while containing a high proportion of CA.

Efficient particulate matter removal by metal-organic frameworks encapsulated in cellulose/chitosan foams

Dandan Hao,Bo Fu,Jiancheng Zhou,Jingyin Liu

Particulate matter (PM) is one of the major air pollutants that is harmful to both environment and human health. Herein, Ti-based metal-organic frameworks (MOFs) of MIL-125 and MIL-125-NH 2 were integrated into bacteria cellulose/chitosan foam (BCH) and used as air filters. A directional freeze-drying approach was used to construct foam matrix, in which the meso-/macropores of polymer skeleton contribute to the required accessibility toward MOFs and minimize gas diffusion barriers. Benefiting from the hierarchically porous structure, the composites foam presented superior filtration properties with high removal efficiencies and low pressure drops. The filtration efficiency of MIL-125-NH 2 @BCH filter for PM 2.5 could exceed 99.5% with a good long-time (30 days) stability. The pressure drop is determined to be 39.4 Pa. The filtration mechanisms are attributed to the electrostatic interaction between MOFs and PM particles, the presence of amine groups, as well as the inhibition effect of fibrous polymer network. This work will shed light on the development of MOF-polysaccharide composites for air purification applications.

Immune-stealth carboxymethyl chitosan-based nanomaterials for magnetic resonance imaging-guided photothermal therapy

Yilin Wang,Wenjie Wang,Xiaoming Wang,Hao Wu,Weifeng Zhao,Changsheng Zhao

Numerous protein-based multifunctional nanomaterials have been studied for biomedical applications. However, the inherent immunogenicity and activation of the complement system of protein-based nanomaterials may cause immunological responses, further leading to hypersensitivity and/or allergic reactions in patients. Herein, carboxymethyl chitosan (CMC) and KMnO 4 are used to develop polysaccharide-based MnO 2 (CM) nanoparticles as facile, effective and low-immunogenicity nanomaterials for magnetic resonance imaging (MRI)-guided photothermal therapy (PTT). As a proof of concept, indocyanine green (ICG) is loaded in the CM nanoplatform to form a CMC-MnO 2 -ICG compound (CMI) for MRI-guided photothermal therapy. In vitro studies show that the proposed CMC-based nanomaterials exhibit excellent hemocompatibility and no significant complement activation . The in vivo biosafety experiments also show that the CMC-based nanomaterials have low immunogenicity and will not cause tissue damage. Moreover, the prepared CMI nanoparticles (NPs) possess outstanding photothermal properties and high longitudinal relaxivity (8.47 mM −1  s −1 ), which achieve successful MRI-guided PTT in tumor-bearing mice. This work draws increasing attention to the hemocompatibility and immunogenicity of high-performance nanoprobes for biomedical applications.

Sonocatalytic degradation of ciprofloxacin using hydrogel beads of TiO2 incorporated biochar and chitosan

Muhammad Zaheer Afzal,Peng Zu,Chun-Miao Zhang,Jing Guan,Chao Song,Xue-Fei Sun,Shu-Guang Wang

Pharmaceuticals are necessary to be removed from environment. Herein TiO 2 incorporated biochar made from pyrolysis of agricultural wastes was encapsulated into chitosan to obtain a novel hydrogel beads. This hydrogel beads executed a dual role as both adsorbent and sonocatalyst, which proved to be suitable for the removal of antibiotic ciprofloxacin (CIP) from water. The results showed that adsorption of CIP followed pseudo first order kinetics model and Langmuir adsorption isotherm model, having maximum adsorption at pH 9. Whereas the degradation was more efficient at pH 6 due to greater standard potential for • OH/H 2 O in acidic media. The degradation was maximum at 150 W of ultrasonic power, then decreased in presence of dissimilar electrolytes and even reduced to 0 in presence of Na 3 PO 4 . Different quenchers such as benzoquinone (BQ), Triethanolamine (TEA) and isopropyl alcohol (IPA) reduced degradation efficiency (DE) and mineralization efficiency (ME). The DE was decreased from 85.23% to 81.50% (BQ), 74.27% (TEA), and 61.77% (IPA) within 25 min. The prepared sonocatalyst was capable of regeneration with DE, remaining sufficiently high (62%) even after four regeneration steps. These results indicate that titanium-biochar/chitosan hydrogel beads (TBCB) are durable and effective for long-term CIP removal.

Carboxymethyl chitosan-grafted polyvinylpyrrolidone-iodine microspheres for promoting the healing of chronic wounds

Jie Yu,Pei Wang,Mengting Yin,Kaiwen Zhang,Xiansong Wang,Bing Han

Durably Antibacterial Cotton Fabric Prepared by a Combination of Betaine and Carboxymethyl Chitosan

Xiao Yuanxiang,Duan Panpan,Shen Guokang,Zheng Weishi,Fu Jiajia,Xu Qingbo,Fu Feiya,Liu Xiangdong

A simple pad-dry-cure modification process is proposed to prepare the antibacterial cotton fabrics with durable antibacterial properties. Two natural antibacterial materials, carboxymethyl chitosan (CMC) and betaine (Bet), were grafted on cotton fiber surface to achieve the goal. FTIR-ATR and XPS results reveal that esterification and amidation reactions have taken place between the CMC, Bet, and the cellulose chains on the surface of cotton fibers. Antibacterial evaluation results confirm the antibacterial capability and the durability of the modified fabrics. The bacterial reduction (BR) rates against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) are higher than 99.99 % and can be kept at a level higher than 95 % even after 20 washing cycles. According to the XRD results presented, the entire modification process wreaks little damage to the crystalline structure of the cotton fabric. Especially, both the water vapor permeability and water absorption capability were improved (371.1 g/m 2 /d and 198 %, respectively) when compared to the original cotton fabric. This work provided a new way to fabricate antimicrobial cotton fabric using bio-based compounds, displaying great application potential in the antibacterial textile industry.

Functionally-Designed Chitosan-based hydrogel beads for adsorption of sulfamethoxazole with light regeneration

Aijiao Zhou,Kai Yang,Xumeng Wu,Guoqing Liu,Tian C. Zhang,Qin Wang,Fan Luo

Adsorption method has been widely used in the removal of emerging contaminants. However, many adsorbents are puzzled by key obstacles for effective and simple regeneration. In this work, the functionally-designed graphitic carbon nitride (g-C 3 N 4 ) embedded chitosan-polyvinyl alcohol composite (g-C 3 N 4 /CS/PVA) hydrogel beads were synthesized for the adsorptive removal of sulfamethoxazole (SMX) from water, and they could be regenerated by light. The adsorption kinetics, isotherm, thermodynamics, and impacting factors were systematically investigated. And the adsorption capacity of the hydrogel for SMX was relatively stable at pH of 4–8, with the maximum adsorption capacities being 5.8 mg g −1 at pH 5. The main adsorption force may be inferred to the electrostatic interactions between SMX and hydrogel beads, and hydrogen bonds between the amino or hydroxyl groups of the hydrogel and the amino of the SMX. The dominance of electrostatic interactions resulted in SMX adsorption being highly dependent on ionic strength. Being irradiated with an ultraviolet lamp for 5 recycles, the hydrogel beads still kept good adsorption capacity. The regeneration behavior was attributed to the photocatalytic degradation of SMX by g-C 3 N 4 . Namely, photocatalytic oxidation reactivated the adsorption sites and increased the release of adsorbed pollutants with improved desorption performance.

Chitosan-enhanced nonswelling hydrogel with stable mechanical properties for long-lasting underwater sensing

Zhijie Zhao,Xuzhe Qin,Lilong Cao,Junjie Li,Yuping Wei

Existing anti-swelling hydrogels with poor mechanical strength restrict their underwater human monitoring as wearable electronic sensing equipment. Herein, a nonswelling double network (DN) hydrogel with strong self-recoverability (97.22%) was developed by adding chitosan (CS) to poly(acrylic acid-2-methoxyethyl acrylate)-Fe 3+ [P(AA-MEA)-Fe] network. Owing to the introduction of CS, the hydrogel displayed excellent nonswelling properties under aqueous solutions (pH = 1, 4 and 7), physiological saline, seawater, dodecane, n-hexane and chloroform. Besides, CS improved mechanical properties of hydrogel through non-covalent network (large stretchability of 1199%, tensile strength of 0.462 MPa and toughness of 2.01 MJ/m 3 ). Surprisingly, the hydrogel still reached the extensibility (1072%) and tensile stress (0.467 MPa) even after immersing in water for 7 days. Fabricating hydrogel as flexible strain sensor, periodic real-time signals of human movements (e.g., joint actions and electronic skin touching) were accurately monitored under the water and seawater. The nonswelling P(AA-MEA)-CS-Fe hydrogel shows huge potential in underwater sensing.