查找使用阿拉丁产品的科研文献

Fabrication of chitosan based luminescent nanoprobe with aggregation-induced emission feature through ultrasonic treatment

Xin Hu,Shengxian Yu,Guang Yang,Wei Long,Teng Guo,Jianwen Tian,Meiying Liu,Xiancai Li,Xiaoyong Zhang,Yen Wei

Chitosan is an abundant natural polysaccharide that contains a lot of amino and hydroxyl groups. It possesses great potential for biomedical applications owing to its low toxicity, biodegradability and low cost. Herein, a novel chitosan-based fluorescent copolymer (WS-CS-TPA) was designed and synthesized via nucleophilic substitution of hexachlorocyclotriphosphazene (HCCP), water-soluble chitosan (WS-CS) and an aggregation-induced emission (AIE) fluorogen (AIEgen) triphenylamine derivative (TPA-NH 2 ). Under ultrasonic treatment, 1.16 g TPA-NH 2 and 1.1 g WS-CS can be conjugated by 0.7 g HCCP at room temperature. The obtained copolymer shows amphiphilic property and could assemble into nanoparticles with size about 100 nm. After self-assembly, TPA-NH 2 was aggregated in the core, thus exhibiting superb AIE feature with intense green fluorescence emission in aqueous media. On the other hand, hydrophilic WS-CS was coated on the surface of nanoparticles and endowed their high water dispersibility. Results from preliminary biological assays suggested that WS-CS-TPA can be internalized by cells and exhibits low cytotoxicity, suggesting their great potential for biological imaging and intracellular drug delivery.

A Natural Eumelanin-Assisted Pullulan/Chitosan Hydrogel for the Management of Diabetic Oral Ulcers

Ying Li,Yajing Xiang,Yuxi Chen,Yingying Wang,Wei Dong,Yan Liu,Xiaoliang Qi,Jianliang Shen

Existing methods for treating diabetic oral ulcers often fall short in clinical environments due to potential bacterial contamination, oxidative harm, and hindered angiogenesis throughout the healing process. Here, a hydrogel patch (HYG2) have been developed for local in situ application. HYG2 comprises oxidized pullulan, quaternized chitosan, and eumelanin nanoparticles derived from cuttlefish ink. These components work together to efficiently heal wounds associated with diabetic oral ulcers. Application begins with a simple local injection that quickly forms a protective barrier over the mucosa, effectively stopping bleeding and counteracting inflammatory agents. HYG2 is distinguished by its strong antibacterial properties and capacity to eliminate reactive oxygen species, promoting bacteria clearance and managing oxidative stress, which accelerates the healing phase from inflammation to tissue regeneration. Additionally, HYG2's 3D structure, incorporating elements from natural sources, offers exemplary support for structural and nutritional cell needs. This enhancement fosters cell adhesion, migration, and proliferation, along with further angiogenesis during mucosal remodeling. Ultimately, HYG2 is fully absorbed by the body after serving its therapeutic functions. Evidence from in vitro and in vivo studies shows that HYG2 hydrogel markedly accelerates mucosal wound repair, making it a promising treatment for diabetic oral ulcers.

Study on nano-chitosan grafting quaternary ammonium salt modified polyacrylamide for flocculation and sterilization

Zheng Zhong,Fengjiao Zhang,Wei Chen,Xiaguo Wei,Yiwen Zhang,Yanbo Lu,Hongbin Luo,Liangqian Fan

ABSTRACT A dual-function chitosan-based flocculant named nano-chitosan-graft-poly(acrylamide and acryloyloxyethyltrimethyl ammonium chloride (NCS-g-P(AM-DAC)) with flocculation and sterilization properties was successfully synthesized by using nano-chitosan (NCS), acrylamide, and acryloyloxyethyltrimethyl ammonium chloride (DAC) under ultraviolet irradiation with 2,2’-Azobis(2- methylpropionamidine) dihydrochloride as the photo-initiator. NCS was obtained via ion cross-linking between chitosan and sodium tripolyphosphate. The structure and physicochemical properties of the product were characterized by various methods. The influence of different factors on the intrinsic viscosity of synthetic copolymer was investigated to optimize the synthetic condition. The flocculation performance of NCS-g-P(AM-DAC) was evaluated. Results showed that the superior flocculation efficiency was acquired under pH = 6 and flocculant dosage of 5 mg L –1 , in which turbidity removal efficiency was above 85%. Considering that the quaternary ammonium salt was grafted and the nanoparticle generated, NCS-g-P(AM-DAC) was also applied to flocculate Escherichia coli (E. coli) suspension to evaluate the sterilization performance. At suitable dosage and pH conditions, the flocculant effectively removed turbidity and bacterial cells. 3D fluorescence spectroscopy analysis of E. coli suspension after the flocculation was conducted to investigate the sterilization mechanism. The results showed that NCS-g-P(AM-DAC) could destroy cell membranes, indicating its bactericidal, not simply antibacterial, effect during flocculation.

Synthesis, characterization of catechin-loaded folate-conjugated chitosan nanoparticles and their anti-proliferative effect

Buyun Liu,Yongli Wang,Qijian Yu,Dapeng Li,Feng Li

PAMAM Grafted Magnetic Chitosan Particles by EDTA Core for Efficient Removal of Cu (II)

Wang Rui,Song Xin,Liu Li,Zhou Chao,Wu Guangfeng

Magnetic particles with active groups on their surfaces can be applied to wastewater purification to remove harmful ions, but the insufficient number of active groups on their surfaces tends to limit their removal rate of ions. Herein, we grafted different generations of dendritic macromolecular polyamidoamine (PAMAM) onto the magnetic chitosan microspheres (MCS) using ethylenediamine tetraacetic acid (EDTA) as core (MCEPs) for the removal of Cu (II). Firstly, 7 μm-sized MCS with good dispersibility was prepared by adjusting conditions such as glacial acetic acid content, emulsifier content and raw material ratio. Secondly, the effect of MCEPs generation, pH and contact time on the adsorption capacity were investigated. The adsorption experiments showed that the MCEPs had a high adsorption capacity, when the adsorbent was the second generation of MCEP (MCEP G2.0), the maximum adsorption capacity can up to 702.9 mg/g and the adsorption process can be completed in 60 min. Moreover, among various isotherms models, MCEP G2.0 was well-fitted by Langmuir adsorption isotherm. Also, adsorption kinetic studies proved that the adsorption mechanism of MCEP G2.0 adsorbent followed the pseudo-second-order kinetic model, demonstrating that the process was chemisorption. The adsorbent has renewability as well, after five adsorption cycles, its adsorption efficiency was still higher than 80%. Therefore, the adsorbent showed a superior adsorption capacity and renewability to remove Cu (II). Graphical

Antioxidant and catalytic reduction activity of green synthesized gold nanoparticles using water-soluble chitosan

Kexin Wang,Hongbo Liang,Shuai Pu,Jin Li,Chunmei Tan,Shiqian Li

Gold nanoparticles (AuNPs) were synthesized with water-soluble chitosan serving as the reducing agent and stabilizer. Subsequently, they were characterized by UV–vis, TEM, FT-IR, and XRD. The impact of water-soluble chitosan concentration and molecular weight on the morphology of the synthesized AuNPs was investigated. The in vitro antioxidant activity of AuNPs against OH·, ABTS·+, DPPH, and NO· was assessed. Additionally, the catalytic reduction activity of AuNPs toward 4-nitrophenol (4-NP) in the presence of NaBH4 was evaluated. The results indicated that various morphologies, including spherical, anisotropic AuNPs, and triangular Au nanoplates with different particle sizes, could be synthesized by controlling the concentration and molecular weight of water-soluble chitosan. It was discovered that the antioxidant and catalytic reduction activity of AuNPs were correlated with their morphology. Spherical AuNPs with a particles diameter of 15 nm exhibited the highest antioxidant activity, with estimated IC50 values of 24.6 ± 1.9, 15.6 ± 3.2, 22.6 ± 1.9, and 15.1 ± 1.9 μg/mL for OH·, ABTS·+, DPPH, and NO·, respectively. Triangular Au nanoplates showed the highest reaction rate constant of0.3889 min−1 and turnover frequency of 7.52 × 10−5mol/(mg·min), as well as the lowest activation energy of 24.1 kJ/mol.

Eco-friendly Grafting of Chitosan as a Biopolymer onto Wool Fabrics Using Horseradish Peroxidase

Xu Lingling,Zhang Nan,Wang Qiang,Yuan Jiugang,Yu Yuanyuan,Wang Ping,Fan Xuerong

Chitosan and enzymes have been extensively used in modification of wool, due to their non-toxic and eco-friendly characteristics, as well as to reduce pollution in textile production. In the present work, chitosan was grafted onto wool fabrics using horseradish peroxidase (HRP) in order to endow wool with outstanding properties. The reaction mechanism, grafting percentage, and properties of chitosan-grafted pretreated wool fabric including wettability, dyeability, shrink resistance, and antibacterial activity were studied. P -hydroxyphenylacetamide (PHAD), as a model compound for tyrosine residues in wool, was used to study the mechanism of HRP-mediated grafting of chitosan onto wool. UV and FTIR analyses indicated that quinones, which are intermediate of HRP/H 2 O 2 -catalyzed PHAD, reacted with the amino groups of chitosan by Schiff base or Michael addition reactions. Scanning electron microscopy (SEM) showed that dichloroisocyanuric acid pretreatment had an etching effect and some substances were deposited onto the wool fiber. SEM and Fourier transform infrared (FTIR) spectroscopy further confirmed the covalent grafting of chitosan onto wool. Compared with chitosan-grafted unpretreated wool, there was an obvious improvement in grafting efficiency of chitosan onto wool fabric, physical and mechanical properties after pretreatment and chitosan grafting on the wool. For chitosan-grafted pretreated wool fabrics, there was no observable change in the thermal behavior, while the hydrophilicity, dyeability, shrinkage resistance, and antibacterial activity were remarkably improved compared to that of untreated wool. The present work offers a new ecologically acceptable process of grafting chitosan on the wool.

Synthesis and properties of pH sensitive carboxymethylated hydroxypropyl chitosan nanocarriers for delivery of doxorubicin

Zhu Lin,Xiaomin Cheng

A novel amphiphilic polymer, carboxymethylated hydroxypropyl chitosan (HPCMS) was successfully synthesized for delivery of doxorubicin (DOX). The chemical structure and thermal stability were characterized by FTIR, 1H NMR and TGA, respectively. In aqueous medium, HPCMS could self-assembled into micelles with a low critical aggregation concentration of 0.54 mg/mL. The DOX-loaded HPCMS micelles showed a considerable drug-loading capacity of around 13 wt%. The prepared micelles were spherical morphology with average hydrodynamic diameter 300-380 nm and zeta potential of around −13 mv. The HPCMS/DOX micelles showed a sustained and pH-dependent drug release behavior in vitro and good stability. The drug release data could be well fitted with the Higuchi kinetic model, suggesting a diffusion-controlled mechanism. The diffusional exponent values indicated non-Fickian diffusion where the diffusion of drug and polymer relaxation had an important role in the process of drug release.

Co-effects of amines molecules and chitosan films on in vitro calcium carbonate mineralization

Jifei Cui,John F. Kennedy,Jun Nie,Guiping Ma

Amines monomers, N , N -dimethylaminoethyl methacrylate (DMAEMA), N , N -dimethylethanolamine (DMEA), 2-dimethylaminoethylamine (DMEDA) and N -methiyldiethanolamine (MDEA) were used to induce the formation of calcium carbonate (CaCO 3 ) crystals on chitosan films, by using (NH4) 2 CO 3 diffusion method at ambient temperature. The obtained CaCO 3 particles were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The influence of reaction variables, such as the additive concentration and their types were also investigated on the products. The morphologies of CaCO 3 crystals, inter-grown in cube-shape, were controlled by DMAEMA and DMEA. It was observed that the morphologies of CaCO 3 changed from the cube grown arms to massive calcite with a hole on the face by increasing the concentrations of DMEDA and MDEA. While the precipitation grew on chitosan film without any organic additive, only single cube-shaped crystals were obtained. By these results the possible mechanisms can be proposed that electronic movement of the groups on the monomer effected ions configuration and molecules absorbed on the exposed surface, resulted the change of the surface energy, which caused the change in the morphology of CaCO 3 .

Multifunctional film of soy protein nanofiber/chitosan/zinc oxide for tomato postharvest freshness preservation

Yi-Lun Wang,Ruonan Li,Xiaoyu Yang,Liang Li

As single-function packaging increasingly fails to meet the demand for environmentally friendly convenience, multifunctional packaging is becoming increasingly important in food applications. In this study, inexpensive soybean protein is used as the raw material for membrane preparation, and it is fibrillated. Chitosan and Zinc oxide nanoparticle were added to it to improve its film-forming property, and a multifunctional film (SCZ) was made. SCZ exhibits high mechanical properties and water resistance. Furthermore, it displays exceptionally high antimicrobial activity (> 99%), antioxidant performance (> 80%), UV-blocking efficacy, and biocompatibility. Due to these multifunctional properties, SCZ has the potential to be used in food packaging applications, as demonstrated by tomato preservation experiments. It maintains good freshness both at room temperature and under refrigerator chilling conditions, and extends shelf life (25 °C, 6 d or 4 °C, 10 d). This research provides a new design concept for sustainable multifunctional food packaging materials.

Chitosan-Oligosaccharide-Bearing Biphasic Calcium Phosphate Bone Cement: Preparation and Angiogenic Activity In Vitro

Jianshen Liu,Xinghua Guo,Qishi Che,Zhengquan Su

Although calcium phosphate bone cement has some advantages (it is easy to form, self-curing, and does not produce heat), some disadvantages remain that limit its clinical application. Therefore, the question of how we can modify CPC and further improve the various properties of calcium phosphate bone cement is a current research hotspot. In this paper, the preparation conditions and technology of biphasic calcium phosphate (BCP) were optimized; chitosan oligosaccharide (COSM) with MW ≤ 3000 Da was added to the optimal formulation of biphasic calcium phosphate cement particles, and its physical and chemical properties were characterized. The results showed that BCP bone cement carrier for clinical operations was successfully constructed by the high-temperature solid-state reaction method, and COSM-BCP bone cement particles were obtained by loading COSM drugs with an angiogenesis effect. Its formula is biphasic calcium phosphate powder with the molar ratio of α-TCP/β-TCP of 1. The curing time of the prepared BCP particles is 24 ± 1 min, the compressive strength is 29.58 ± 1.89 MPa, and the porosity reaches 52.09%. The loaded COSM can be released continuously and stably in vitro, and has the effect of promoting angiogenesis. The safety evaluation of COSM-BCP bone cement particles and the preliminary pharmacodynamic study of its angiogenesis in vitro provide a promising clinical application basis for the development of drug-loaded biological bone substitute materials.

Cellulose/chitosan film based triboelectric-piezoelectric coupled nanogenerator for wearable mechanosensing and energy harvesting

Zewei Ye,Qingyu Meng,Haomeng Yu,Shitao Shi,Yuanyuan Wang,Zhuyue Lan,Jiaqi Liao,Qingfeng Sun,Xiaoping Shen

Intelligently harnessing energy from the surrounding environment through various nanogenerators presents an ideal avenue to enable self-powered electronics. Herein, we developed a lightweight, flexible bilayer-structure coupled nanogenerator composed of a Hydroxypropyl cellulose (HPC)/chitosan (CTS)/carbon nanotube (CNT) film as the positive triboelectric layer, (PVDF)/polydimethylsiloxane (PDMS) aerogel as the negative layer. The triboelectric positive layer incorporates HPC and CTS biopolymers with multiple functional groups, thereby enhancing the polarity of the positive layer. Meanwhile, the incorporation of CNT in the biopolymer triboelectric film diminishes the contact impedance of the film, further increasing the voltage output (V OC ). The negative PVDF/PDMS aerogel layer, which exhibits both triboelectric and piezoelectric functions, features a high specific surface area, thus allowing for the coexistence of triboelectric and piezoelectric charges. This triboelectric-piezoelectric coupled nanogenerator displays an impressive sensitivity of 112.5 mV kPa −1 , excellent stability (maintaining consistent V OC over 10,000 cycles), mechanical robustness, and robust energy harvesting capabilities. The simultaneous generation of triboelectric charges and piezoelectric charges due to the high specific surface area is proposed for the first time, offering significant promise for diverse applications ranging from various mechano-sensing to mechanical energy collection and storage.