基于纳米脂质体的马卡制剂的制备及其性质研究

以大豆磷脂为载体，以葡萄糖液作为分散介质，采用旋转薄膜蒸发法，发展了一种新的马卡纳米制剂制备方法．考察了该方法制备的不同药脂比的马卡纳米制剂的粒径及其Zeta电位，并对马卡的包封率、制备的马卡纳米制剂的胶体溶液物理稳定性以及冻干粉剂有关性质进行了研究．结果表明，不同药脂比的马卡制剂的平均粒径在100～150nin之间，Zeta电位均小于-30mV：通过该方法获得的马卡纳米制剂的包封率高，其胶体溶液具有很好的物理稳定性，30d内，其粒径未发生显著变化，而且冻干粉剂的水再分散性较好．     

锐钛型纳米二氧化钛对河蚬氧化应激的影响

为评价纳米二氧化钛（TiO2-NPs）对河蚬（Corbicula fluminea）的毒性效应,采用5、50、100 mg/L浓度锐钛型TiO2-NPs对河蚬暴露处理24 h、48 h、96 h和192 h,测定其鳃、消化腺和斧足肌肉组织中钛含量以及谷胱甘肽S转移酶（GST）、超氧化物歧化酶（SOD）的活性。结果表明：（1）在相同暴露时间下,河蚬3种组织的平均钛含量均显著上升并高于空白对照组（P<0.05）;随暴露时间延长,消化腺和斧足肌肉中平均钛含量总体上呈上升趋势,且消化腺中钛含量高于斧足组织,而低、中浓度组鳃组织平均钛含量处于较稳定水平;暴露24～192 h,鳃、消化腺和斧足肌肉中平均钛含量分别为0.73～3.50、2.88～32.37、1.15～3.11 μg/g;（2）在暴露初期,河蚬3种组织的GST活性不同程度上升;随暴露时间延长,鳃和消化腺中GST活性先显著下降、后上升,斧足肌肉中GST活性呈现逐步下降趋势;暴露24～192 h,鳃、消化腺和斧足肌肉中GST活性分别为97.39～371.44、164.92～837.22、63.39～247.75 U/mg;（3）暴露24 h后,3个浓度组河蚬鳃和斧足肌肉中SOD活性均明显上升,低浓度组消化腺SOD活性也显著上升;随暴露时间延长,3种组织中SOD活性均呈现逐渐下降趋势,且SOD活性下降幅度与处理浓度呈正相关;暴露24～192 h,鳃、消化腺和斧足肌肉中SOD活性分别为7.68～27.05、3.63～16.92、4.25～43.08 U/mg。研究表明,3种浓度TiO2-NPs暴露导致钛在河蚬体内显著富集并引起氧化应激反应,其对河蚬具有明显的毒性效应。     

Influence of Molecular Weight and Degree of Deacetylation of Low Molecular Weight Chitosan on the Bioactivity of Oral Insulin Preparations

The objective of the present study was to prepare and characterize low molecular weight chitosan (LMWC) with different molecular weight and degrees of deacetylation (DDA) and to optimize their use in oral insulin nano delivery systems. Water in oil nanosized systems containing LMWC-insulin polyelectrolyte complexes were constructed and their ability to reduce blood glucose was assessed in vivo on diabetic rats. Upon acid depolymerization and testing by viscosity method, three molecular weights of LMWC namely, 1.3, 13 and 18 kDa were obtained. As for the DDA, three LMWCs of 55%, 80% and 100% DDA were prepared and characterized by spectroscopic methods for each molecular weight. The obtained LMWCs showed different morphological and in silico patterns. Following complexation of LMWCs with insulin, different aggregation sizes were obtained. Moreover, the in vivo tested formulations showed different activities of blood glucose reduction. The highest glucose reduction was achieved with 1.3 kDa LMWC of 55% DDA. The current study emphasizes the importance of optimizing the molecular weight along with the DDA of the incorporated LMWC in oral insulin delivery preparations in order to ensure the highest performance of such delivery systems.     

Magnesium oxide nanoparticles induce systemic resistance in tomato against bacterial wilt disease

Bacterial wilt is a serious problem affecting many important food crops. Recent studies have indicated that treatment with biotic or abiotic stress factors may increase the resistance of plants to bacterial infection. This study investigated the effects of magnesium oxide nanoparticles (MgO NP) on disease resistance in tomato plants against Ralstonia solanacearum, as well as its antibacterial activity. The roots of tomato seedlings were inoculated with R. solanacearum and then immediately treated with MgO NP; the treated plants showed very little inhibition of bacterial wilt. In contrast, when roots were drenched with a MgO NP suspension prior to inoculation with the pathogen, the incidence of disease was significantly reduced. Rapid generation of reactive oxygen species such as O₂^?˙ radicals was observed in tomato roots treated with MgO NP. Further O₂^?˙ was rapidly generated when tomato plant extracts or polyphenols were added to the MgO NP suspension, suggesting that the generation of O₂^?˙ in tomato roots might be due to a reaction between MgO NP and polyphenols present in the roots. Salicylic acid‐inducible PR1, jasmonic acid‐inducible LoxA, ethylene‐inducible Osm, and systemic resistance‐related GluA were up‐regulated in both the roots and hypocotyls of tomato plants after treatment of the plant roots with MgO NP. Histochemical analyses showed that β‐1,3‐glucanase and tyloses accumulated in the xylem and apoplast of pith tissues of the hypocotyls after MgO NP treatment. These results indicate that MgO NP induces systemic resistance in tomato plants against R. solanacearum.     

基于介孔二氧化硅纳米粒子的农药可控释放研究进展

鉴于介孔二氧化硅纳米粒子（mesoporous silica nanoparticles,MSNs）具有比表面积大、孔径可调节、孔道均匀、内外表面易于修饰和生物相容性好等优点,其在药物控释方面的应用已成为当前国内外研究的热点。本文综述了介孔二氧化硅纳米粒子的制备方法（软模板法、硬模板法和自模板法）,表征技术[扫描电镜分析（SEM）、透射电镜分析（TEM）、X射线衍射分析（XRD）、物理吸附分析、热重和差热分析（TGA-DTA）和傅里叶红外光谱分析（FT-IR）]及其在农药领域的研究应用状况,探讨了以介孔二氧化硅纳米粒子作为农药载体时存在的问题,并对其应用前景进行了展望。     

介孔硅纳米颗粒对水稻镉吸收的影响

采用盆栽试验研究了介孔硅纳米颗粒(MSN)对水稻Cd吸收的影响。结果表明,MSN提高了土壤溶液的p H值,从而显著降低了土壤Cd的生物有效性,施用量为0.5%、1.0%和2.0%的MSN处理组土壤有效态Cd含量分别下降63.07%、81.30%和93.02%。MSN对Cd污染土壤上水稻生长也有一定的促进作用,显著降低了盆栽水稻籽粒中Cd的含量,0.5%、1.0%和2.0%MSN处理组水稻籽粒中Cd含量从0.363 mg/kg分别下降到0.045 5、0.032 5、0.020 7 mg/kg,均达国家标准。因此,介孔硅纳米颗粒可用于镉污染土壤的修复治理。     

氮掺杂碳纳米粒子对土壤氮素转化及油菜苗期生长的影响

为了解氮掺杂碳纳米粒子(N-CNPs)对土壤氮素转化和植物生长的影响,以油菜品种湘油15号为研究材料,以常规硝化抑制剂双氰胺(DCD)为阳性对照,采用室内盆栽法分析不同剂量N-CNPs对移植油菜后土壤氮素形态、含量以及油菜生长状况和氮肥利用率的影响。结果表明:N-CNPs能显著提高土壤NH_4~+-N含量同时降低NO_3~--N含量,与单施尿素相比,NH_4~+-N最大提升118%,NO_3~--N最大降低49.74 mg/kg。5‰和15‰的N-CNPs硝化抑制能力较5%的DCD高,在23 d时差异达到了显著水平。5‰的N-CNPs可增加油菜苗期氮素积累量,其氮肥利用率较单施尿素提升了16.77个百分点。N-CNPs剂量提升至15‰,油菜生长受到抑制。总体而言,N-CNPs具有较好的硝化抑制能力,提升氮肥利用率;5‰剂量的N-CNPs能促进油菜苗期的生长和氮素的积累。     

磁性纳米粒子的合成及应用研究进展

磁性纳米结构是近年来化学、材料及生物领域交叉性研究热点,在催化、生物技术、磁共振成像、数据存储和环境修复等方面应用非常广泛。随着合成、检测技术的发展,对磁性纳米粒子的尺寸和形貌控制日趋完善。在设计带有特定活性点、配体、酶、手性催化剂、药物以及其它复杂客体的多功能磁性纳米体系及其组装结构的基础上,通过合成、包裹和功能化新技术的发展和完善,磁性粒子在各个领域的大规模、经济的应用已经实现。对磁性纳米结构的合成技术和方法进行了讨论,并对其在不同领域内的应用进行了阐述。     

Adsorption of Cationic Dyes on a Magnetic 3D Spongin Scaffold with Nano-Sized Fe3O4 Cores

The renewable, proteinaceous, marine biopolymer spongin is yet the focus of modern research. The preparation of a magnetic three-dimensional (3D) spongin scaffold with nano-sized Fe₃O₄ cores is reported here for the first time. The formation of this magnetic spongin–Fe₃O₄ composite was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermal analysis (DTA) (TGA-DTA), vibrating sample magnetometer (VSM), Fourier-transform infrared spectroscopy (FTIR), and zeta potential analyses. Field emission scanning electron microscopy (FE-SEM) confirmed the formation of well-dispersed spherical nanoparticles tightly bound to the spongin scaffold. The magnetic spongin–Fe₃O₄ composite showed significant removal efficiency for two cationic dyes (i.e., crystal violet (CV) and methylene blue (MB)). Adsorption experiments revealed that the prepared material is a fast, high-capacity (77 mg/g), yet selective adsorbent for MB. This behavior was attributed to the creation of strong electrostatic interactions between the spongin–Fe₃O₄ and MB or CV, which was reflected by adsorption mechanism evaluations. The adsorption of MB and CV was found to be a function of pH, with maximum removal performance being observed over a wide pH range (pH = 5.5–11). In this work, we combined Fe₃O₄ nanoparticles and spongin scaffold properties into one unique composite, named magnetic spongin scaffold, in our attempt to create a sustainable absorbent for organic wastewater treatment. The appropriative mechanism of adsorption of the cationic dyes on a magnetic 3D spongin scaffold is proposed. Removal of organic dyes and other contaminants is essential to ensure healthy water and prevent various diseases. On the other hand, in many cases, dyes are used as models to demonstrate the adsorption properties of nanostructures. Due to the good absorption properties of magnetic spongin, it can be proposed as a green and uncomplicated adsorbent for the removal of different organic contaminants and, furthermore, as a carrier in drug delivery applications.     

基于复合纳米材料和酶切信号放大电化学适体传感器检测沙门氏菌

【目的】沙门氏菌是食品中致病菌检测的一项重要指标。本研究拟构建一种实用性更强的用于沙门氏菌检测的新型电化学适配体传感器,以克服各种沙门氏菌传统检测方法的缺陷。【方法】通过混合还原氧化石墨烯(rGO)溶液与甲苯胺蓝(Tb)溶液制得Tb-rGO复合物,再将此复合物分散于纳米金(Au NPs)溶胶中得到Au NPs-Tb-rGO复合物。最后将Au NPs-Tb-rGO复合物与带有氨基的DNA链(S1)孵育得DNA-复合纳米材料(S1-Au NPs-Tb-rGO)。通过金硫键将沙门氏菌适配体互补链(S2)修饰在金电极表面,以己硫醇为封闭剂消除非特异性吸附后,滴涂沙门氏菌适配体(Apt)于电极表面,使Apt与S2杂交结合。将修饰好的电极浸入含有沙门氏菌与核酸外切酶I(Exo I)的混合液中,基于Exo I信号放大效应,利用适配体对沙门氏菌的特异性结合作用,循环带离适配体,再通过S1-Au NPs-Tb-rGO中的S1与S2杂交将S1-Au NPs-Tb-rGO负载到电极表面,监测电极表面的电化学信号,并对在菌液中的孵育时间、Exo I浓度和S1-Au NPs-Tb-rGO浓度进行优化,构建沙门氏菌电化学适配体传感器。使用该传感器,对大肠杆菌、金黄色葡萄球菌、志贺氏菌、单增李斯特菌和阪崎肠杆菌进行检测,以确定沙门氏菌电化学适配体的特异性;对6×10~2—6×10~6 cfu/mL的沙门氏菌进行检测,以确定沙门氏菌电化学适配体传感器的敏感性;对羊奶样品进行检测,以确定沙门氏菌电化学适配体传感器的实用性。【结果】所建立的沙门氏菌电化学适配体传感器在菌液中的最佳孵育时间为1 h,Exo I的最适浓度为0.6 U·μL~(-1),S1-Au NPs-Tb-rGO的最适浓度为200 nmol·L~(-1)。在进行沙门氏菌的检测时,沙门氏菌与Apt特异结合,S1-Au NPs-Tb-rGO复合纳米材料被结合到电极表面使其线性伏安曲线氧化峰升高。特异性试验结果表明,所建立的方法仅对沙门氏菌的检测有电信号响应,而对非目标菌无响应。敏感性试验结果表明,所构建的沙门氏菌电化学适配体传感器,具有很高的敏感性,对沙门氏菌检测的敏感性达200 cfu/mL。使用建立的沙门氏菌电化学适配体传感器对羊奶中的沙门氏菌含量进行测定,加标回收率在91.6%—106.3%,结果令人满意。【结论】所建立的沙门氏菌电化学适配体传感器具有操作简便、检测范围宽、检出限低和成本低廉等优点,有望应用于食品工业中沙门氏菌的现场快速定量检测。