Temperature/pH/magnetic triple‐sensitive nanogel–hydrogel nanocomposite for release of anticancer drug

Hydrogels, nanogels and nanocomposites show increasing potential for application in drug delivery systems due to their good chemical and physical properties. Therefore, we were encouraged to combine them to produce a new compound with unique properties for a long‐term drug release system. In this regard, the design and application of a nanocomposite hydrogel containing entrapped nanogel for drug delivery are demonstrated. To this aim, we first prepared an iron oxide nanocomposite nanogel based on poly(N‐isopropylacrylamide)‐co‐((2‐dimethylaminoethyl) methacrylate) (PNIPAM‐co‐PDMA) grafted onto sodium alginate (NaAlg) as a biocompatible polymer and iron oxide nanoparticles (ION) as nanometric base (PND/ION‐NG). This was then added into a solution of PDMA grafted onto NaAlg. Through dropwise addition of mixed aqueous solution of iron salts into the prepared polymeric solution, a novel hydrogel nanocomposite with excellent pH, thermal and magnetic responsivity was fabricated. The synthesized samples were fully characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy with energy‐dispersive X‐ray analysis, vibrating sample magnetometry and atomic force microscopy. A mechanism for the formation of PNIPAM‐co‐PDMA/NaAlg‐ION nanogel–PDMA/NaAlg‐ION hydrogel and PND/ION nanogel is suggested. Swelling capacity was measured at various temperatures (25 to 45 °C), pH values (from 2 to 11) and magnetic field and under load (0.3 psi) and the dependence of swelling properties of the nanogel–hydrogel nanocomposite on these factors was well demonstrated. The release rate of doxorubicin hydrochloride (DOX) as an anticancer drug was studied at different pH values and temperatures in the presence and absence of a magnetic field. The results showed that these factors have a high impact on drug release from this nanocomposite. The result showed that DOX release could be sustained for up to 12.5 days from these nanocomposite hydrogels, significantly longer than that achievable using the constituent hydrogel or nanogel alone (<1 day). The results indicated that the nanogel–hydrogel nanocomposite can serve as a novel nanocarrier for anticancer drug delivery. © 2019 Society of Chemical Industry     

Development of Core-Shell Nanoparticle Drug Delivery Systems Based on Biomimetic Mineralization

Among various drug-delivery systems, core-shell nanoparticles have many advantages. Inspired by nature, biomimetic synthesis has emerged as a new strategy for making core-shell nanoparticles in recent years. Biomimetic mineralization is the process by which living organisms produce minerals based on biomolecule templating that leads to the formation of hierarchically structured organic–inorganic materials. In this minireview, we mainly focus on the synthesis of core-shell nanoparticle drug-delivery systems by biomimetic mineralization. We review various biomimetic mineralization methods for fabricating core-shell nanoparticles including silica-based, calcium-based and other nanoparticles, and their applications in drug delivery. We also summarize strategies for drug loading in the biomolecule-mineralized core-shell NPs. Current challenges and future directions are also discussed.     

Synthesis of nanoporous Baghdadite by a modified sol-gel method and its structural and controlled release properties

In this research, a bimodal nanoporous Baghdadite (NB) (Ca3ZrSi2O9) was prepared by a modified sol-gel method using P123 as a surfactant. The effects of P123's contents on the structural and textural properties as well as the drug delivery behavior of NB were assessed in vitro. The usage of P123 offered a new route for the synthesis of NB. The synthesized NB samples with different amounts of P123 were studied through X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), N2 adsorption-desorption, field emission scanning electron microscopy (FESEM) equipped with energy-dispersive X-ray analysis spectroscopy (EDAX) and transmission electron microscopy (TEM). The results showed that a single-phase Baghdadite was obtained by this new method at the calcination temperature of 800?°C. It was found that an increase in P123's content up to 0.025?mol changed the morphology of NB samples from mountain-like to needle-like. The potential application of NB samples as drug delivery agents was assessed by estimating their release properties up to 240?h. This research revealed that the synthesized Baghdadite could be used as a potential nanoporous carrier with controlled release capability in bone tissue regeneration.     

Novel strategy for encapsulation and targeted delivery of poorly water-soluble active substances

Carriers for targeted delivery and controlled release of poorly water-soluble active substances (PWSAS) are facing three challenges: (a) the encapsulation issues, (b) limitations of PWSAS water solubility, and (c) burst drug release which can be pharmacologically dangerous and economically inefficient. The present study brings a novel strategy for encapsulation and controlled release of PWSAS—caffeine in concentrations which are higher than its maximal water solubility without the possibility of burst effect. The modification of hydrophilic carrier based on poly(methacylic acid) was done using casein and liposomes. To further increase the maximal caffeine loading inside the carrier nicotinamide was used. The release study of the encapsulated PWSAS was elaborated with respect to morphology of the carriers and interactions that could be established between its structural components. The carriers swelling and the release of caffeine and nicotinamide were also investigated depending on caffeine concentration, the presence of different liposomal formulations and the volume ratio of liposomal formulation, in three media with different pH simulating the path of the carrier through the human gastrointestinal tract. The synthesized carriers are promising candidates for encapsulation of PWSAS in concentrations which are higher than its maximal water solubility and for the targeted delivery of those dosages.     

可拆装高架火炬的应用

结合工程实例,介绍了我国第一座可拆装高架火炬的基本原理及组成,并对可拆装高架火炬与普通高架火炬在安全、技术、安装、维修、占地面积、投资等方面进行了比较,还分析了高架火炬未来的发展趋势.     

GSM无线公话产品中的干扰研究

GSM90 0 /1 80 0固定无线公用电话桌面型话机在开发过程中遇到严重的噪音问题 ,一度成为开发工作的瓶颈。本文就这一噪音问题进行了分析与测试 ,并针对干扰源采取相应的措施 ,在产品开发中付诸应用 ,最终解决了 GSM桌面型无线公话的噪音问题     

某型飞机航姿系统综合检查仪的研究与设计

简述了航姿系统综合检查仪的功能、工作原理以及整体设计方案;采用SDC/DSC模块来发送和接收同步器信号,解决了航姿系统中轴角转换的数字化问题,使检测仪的体积大大减小的同时提高了航姿系统检测精度;提出了小波去噪抗干扰技术,滤除了交流电源产生的噪声;应用改进的广义似然比法和Wald序惯概率比法（SPRT）实现了对系统软故障的检测;本检查仪精度高,操作简单,使用方便,满足机务维护的要求.     

含生物功能基团磷脂胆碱的聚乳酸的合成反应

用天然甘油磷脂胆碱开环丙交酯,以获得具有仿生功能的生物降解聚乳酸.采用1H-NMR、FT-IR确证在聚合物结构中引入了生物功能基团磷脂胆碱.通过1H-NMR和GPC测定分子量及其分布,研究了反应时间和温度对聚合物分子量扣产率的影响,聚合物产率达80%以上.将磷脂引入聚乳酸链段中得到可全降解的、生物相容性好的磷脂高分子.这一新的思路可以用于合成一系列新型的药物载体和组织工程支架材料.     

缝纫设备输送动力装置的分析

文章介绍了几种缝纫设备输送动力装置的送布原理，认为应针对不同的面料特性及经制工艺要求，选用合适的设备输送系统。