肝素化壳聚糖季铵盐／壳聚糖复合膜抗凝血性能的研究

以壳聚糖季铵盐，壳聚糖为基本原材料，选用戊二醛为交剂剂及固定剂，制备一种物理机械性能较优的抗凝血材料。探讨了戊二醛及肝素钠两者用量对肝素化程度及血液生的影响。     

Effects of pretreatments and modifiers on electrochemical properties of carbon paste electrodes

The electrochemical properties of carbon paste electrodes (CPEs), including unmodified and modified with protein and polycations, were investigated by impedance spectroscopy (IS) using ferricyanide and ferrocene monocarboxylic acid (FcMA) as redox probes. Various electrochemical pretreatments were applied to the unmodified CPE. The heterogeneous charge transfer rate constant of ferro/ferricyanide couple is enhanced by 2 to 10 times compared with that obtained at untreated electrodes. It was found that for ferricyanide the more suitable pretreatments are successive cyclic voltammetric scans, cathodization and a square wave-like stepping rather than high-potential anodization. However, the pretreatment only exhibits a slight effect on the kinetics of FcMA. At the CPEs containing modifier, the electron transfer rate of the redox couple depends more on the pH of electrolyte solution if ferro/ferricyanide is used. The results can be explained by the differently charged states of the CPEs that were caused by the protonation or deprotonation of the modifiers in various pH solutions and demonstrate the importance of the electrostatic interaction on the kinetics of the highly polar species such as ferricyanide. The different adsorptive behavior of ferricyanide and FcMA is also discussed.     

抗坏血酸和尿酸在甘氨酸-壳聚糖修饰玻碳电极上的电化学行为及测定

制备了甘氨酸-壳聚糖复合膜修饰玻碳电极(Gly-CTS/GCE),研究了抗坏血酸(AA)和尿酸(UA)在该修饰电极上的电化学行为。结果表明在pH=5.59的磷酸盐缓冲溶液中,AA、UA在Gly-CTS/GCE上均产生灵敏的不可逆氧化峰,其峰电流与浓度在一定范围内呈良好的线性关系。对AA和UA混合溶液平行测定7次,相对标准偏差分别为4.6%、2.9%,表明该电极重现性和稳定性良好。AA、UA在Gly-CTS/GCE电极上的氧化峰峰电位相差340mV,据此可实现对二者的同时检测,并可应用于实际样品测定。     

高效抗菌Cu2+-壳聚糖季铵盐/丙烯酸复合物的制备

以过硫酸铵为引发剂,在壳聚糖季铵盐（HACC）上接枝丙烯酸（AAc）并络合Cu²⁺,制备了具有高效抗菌性能的HACC-g-PAAc-Cu²⁺复合物.采用红外光谱（FTIR）和核磁共振波谱（¹H NMR）表征了壳聚糖季铵盐接枝改性前后的化学结构变化;利用紫外-可见吸收光谱（UV-Vis）、Cu²⁺选择电极和热失重分析（TGA）表征了壳聚糖季铵盐接枝前后负载Cu²⁺的能力;测定了HACC-Cu²⁺和HACC-g-PAAc-Cu²⁺对金黄色葡萄球菌及大肠杆菌的最小抑菌浓度,并对小鼠经口摄入毒性和兔皮肤敷涂刺激性进行了考察.研究结果表明,在壳聚糖季铵盐上负载Cu²⁺能够有效提高其抗菌性;接枝丙烯酸能提高HACC负载Cu²⁺的能力和抗菌性,Cu/HACC结构单元的摩尔比由接枝前的3：7提高到接枝后的1：1;对金黄色葡萄球菌的最小抑菌浓度由60 mg/L下降到9.2 mg/L,对大肠杆菌的最小抑菌浓度由37 mg/L下降到6.3 mg/L,无摄入毒性和皮肤刺激性.     

Chitosan-based self-healing hydrogel for bioapplications

A chitosan-based biocompatible self-healing hydrogel has been facilely prepared and used for bioapplications.     

Decorated CuO nanoparticles over chitosan-functionalized magnetic nanoparticles: Investigation of its anti-colon carcinoma and anti-gastric cancer effects

In this study, a green protocol for supporting CuO nanoparticles over chitosan-modified amino-magnetic nanoparticles is described. The physicochemical and morphological properties of the desired nanocomposite assessed by various techniques like ICP, FT-IR, FE-SEM, EDX, TEM, XRD and VSM. In the oncological part of the recent study, the Cu(NO₃)₂, Fe₃O₄, and Fe₃O₄-NH₂@CS/CuO nanocomposite cell viability was very low against human gastric cancer cell lines i.e. MKN45, AGS, and KATO III and human colorectal carcinoma cell lines i.e. HT-29, HCT 116, HCT-8 [HRT-18], and Ramos.2G6.4C10. The IC50 of Fe₃O₄-NH₂@CS/CuO nanocomposite against MKN45, AGS, KATO III, HT-29, HCT 116, HCT-8 [HRT-18], and Ramos.2G6.4C10 cell lines were 517, 525, 544, 282, 214, 420, and 477 µg/mL, respectively. Thereby, the best anti-gastro-duodenal cancers findings of our Fe₃O₄-NH₂@CS/CuO nanocomposite was seen in the HCT 116 cell line case.     

Chitosan/UiO-66 composites as high-performance adsorbents for the removal of methyl orange in aqueous solution

UiO-66 and chitosan/UiO-66 composites were successfully synthesized by varying the mass addition of chitosan which were 0%, 2.5%, 5%, 10%, and 20% of the mass of UiO-66, denoted as UiO-66, Cs(2.5)/UiO-66, Cs(5)/UiO-66, Cs(10)/UiO-66, and Cs(20)/UiO-66, respectively. UiO-66 was modified with chitosan using the impregnation process. The X-ray diffraction patterns of the synthesized materials showed characteristic peaks at 2θ of 7.25° and 8.39°, which matched to that of the reported UiO-66. In addition, the Fourier transform infrared spectroscopy spectra of the materials showed absorption bands at the same wavenumber as UiO-66 and chitosan previously reported. The surface morphology of UiO-66 observed from scanning electron microscopy images was in the form of agglomerated small cube particles, where the smaller particles were observed for Cs(10)/UiO-66. From the N₂ adsorption isotherms, it was found that the Brunauer-Emmett-Teller surface areas of UiO-66, Cs(5)/UiO-66, and Cs(10)/UiO-66 materials were 825.7 m²/g, 835.4 m²/g, and 882.2 m²/g, respectively. The results of the study on adsorption of methyl orange in aqueous solutions showed that Cs(5)/UiO-66 had the highest adsorption capacity of 370.37 mg/g and followed the pseudo–second-order adsorption kinetic with a Langmuir isotherm model.     

Fluorescent Detection of Cu(Ⅱ) by Chitosan-based AIE Bioconjugate

Detection of Cu(Ⅱ) is very important in disease diagnose, biological system detection and environmental monitoring. Previously, we found that the product TPE-CS prepared by attaching the chromophores of tetraphenylethylene(TPE) to the chitosan(CS) chains showed excellent fluorescent properties. In this study, we tried to use TPE-CS for detecting Cu(Ⅱ) because of the stable complexation of CS with heavy metals and the luminosity mechanism of the Restriction of Intramolecular Rotations(RIR) for aggregation-induced emission(AIE)-active materials. The fluorescence intensity changed when TPE-CS was contacted with different metal ions, to be specific, no change for Na~+, slightly increase for Hg~(2+), Pb~(2+), Zn~(2+), Cd~(2+), Fe~(2+), Fe~(3+) due to the RIR caused by the complexation between CS and metal ions. However, for Cu~(2+), an obvious fluorescence decrease was observed because of the Photoinduced-Electron-Transfer(PET). Moreover, we found that the quenched FL intensity of TPE-CS was proportional to the concentration of Cu(Ⅱ) in the range of 5 μmol/L to 100 μmol/L, which provided a new way to quantitatively detect Cu(Ⅱ) . Besides, TPE-CS has excellent water-solubility as well as absorbability(the percentage of removal, R = 84%), which is an excellent detection probe and remover for Cu(Ⅱ) .     

γ-Ray-Radiation-Scissioned Chitosan as a Gene Carrier and Its Improved in uitro Gene Transfection Performance

Chitosan (CS) is expected to be an ideal gene carrier for its high biosafety. In this work, CS with low molecular weight were prepared through the γ-ray radiation on the acetic acid solution of CS. The CS chains were scissioned under the γ-ray radiation, and the molecular weight (MW) of CS decreased with the absorbed dose. When the absorbed dose was above 30 kGy, the molecular weight of CS decreased about an order of magnitude. The γ-ray-radiation-scissioned CS can e ectively bind with plasmid (pEGFP) through complex coacervation method, forming pEGFP/ γ-ray-radiation-scissioned CS complex particles with a size of 200-300 nm. The complex particles have good stability and little cytotoxicity. The in uitro gene transfection efficiencies of the pEGFP/ γ-ray-radiation-scissioned CS complex particles were investigated by fluorescence microscope and flow cytometry. The results showed that the gene vectors using γ-ray-radiation-scissioned CS as the carrier will possess better gene transfection efficiency than those using natural high-MW CS as the carrier. The higher the absorbed dose, the smaller the MW of CS and the better transfection efficiency of the corresponding gene vector. This work provides a green and simple method on the preparation of CS-based gene vectors with high efficiency and biosafety.     

粘度法预测聚乙二醇/壳聚糖体系的相容性

甲壳素在自然界的含量很大，仅次于纤维素，是一种颇具应用潜力的天然高分子．可由甲壳素经脱酸基化制得壳聚糖．由于其分子中存在氨基，因此能溶解干酸性水溶液中，并以聚电解质的形式存在，近来用壳聚糖制得的纤维膜应用于药物、食品等的分离和纯化、污水的处理，分离效果好，且不带入任何化学杂质．在壳聚糖纤维膜制作及与纤维的混纺过程中，都要探讨它与其它相应高聚物的相容性[1]．我们以相容的壳聚糖（chitosan）／聚乙二醇（PEG）体系为例，采用粘度法讨论其分子间的相互作用，并预测它们的相容性．壳聚糖的基本结构为1实验部分1.1…