生物高分子材料在药物传递系统中的降解 Ⅱ.降解动力学及应用

生物高分子材料在现代药物传递系统中不仅起着载体的作用,而且同时影响和控制药物的缓释机理。文章是《生物高分子材料在药物传递系统中的降解Ⅰ.机理与表征方法》的续篇,主要阐述了生物高分子材料在药物传递系统中的降解动力学。     

生物高分子材料在药物传递系统中的降解 Ⅰ.机理与表征方法

生物高分子材料在现代药物传递系统中不仅起着载体的作用,而且还影响和控制药物的缓释机理。文章为第一部分,主要介绍生物高分子材料在药物传递系统中的降解机理与表征方法。     

天然糖类纳米药物传递系统的研究进展

纳米技术作为影响未来人类生活的世界三大新兴科技之一,其与药物传递系统的融合,既可以将药物的药理作用极大限度地发挥出来,又克服了药物本身的局限性.天然糖类的来源十分广泛,不仅价格低廉、无毒性,且具有良好的生物相容性和生物可降解性,被广泛用于纳米药物传递系统.本文对纳米药物传递系统的体系组成进行了归纳,重点阐述了常见糖类及...     

葡萄糖敏感苯硼酸基高分子纳米药物传输体系

近年来,智能葡萄糖敏感自调式药物传递系统备受关注。这种智能药物释放系统能够模拟胰腺分泌胰岛素的生理模式而精准调控药物释放并控制血糖水平,在糖尿病治疗中具有良好的应用前景。其中,苯硼酸(PBA)功能化的葡萄糖敏感高分子纳米载体成为近年来的研究热点之一。该类材料具有体系稳定、可长期储存、可逆的葡萄糖敏感性能等优势。根据响应因素不同,葡萄糖敏感药物传递系统可分为pH响应、温度响应和光响应等类型。本文重点介绍了基于PBA的葡萄糖敏感高分子纳米药物载体的发展过程、性能和应用,并对该领域的发展前景进行了展望。     

纳米粒子在药物传递中的应用

目前,利用纳米粒子传递药物并用于恶性肿瘤组织的靶向识别,进一步提高肿瘤的诊断和治疗水平是一个比较热点的领域,人们期望用制备容易、价格便宜、毒性小的纳米技术来提高肿瘤的治疗效率。然而,由近年的报道来看,所摄入的纳米粒子仅有约0.7%能够到达肿瘤部位,传递效率较低,这无疑加大了治疗应用的难度。本综述中,我们分析了造成纳米粒子靶向药物转运效率较低的原因,包括纳米粒子的转运途径,纳米粒子转运过程中所遇到的屏障,纳米粒子在体内的清除途径等;随后我们介绍了较早应用的聚合物纳米粒子、磁性氧化铁纳米粒子以及目前广泛研究的介孔二氧化硅纳米粒子在药物传递系统构建中的应用情况,还介绍了细胞膜仿生纳米粒子在药物传递系统中的应用;最后,对纳米粒子在药物传递中的研究进行总结和展望。我们希望通过对纳米粒子传递药物的系统研究,进一步促进纳米粒子在药物传递上的研究,加速纳米药物的临床应用。     

导电聚合物在药物可控释放领域的应用

导电聚合物(conducting polymers,CPs)是一类与金属具有相似的电、磁和光学特性的有机聚合物,电刺激会引起其氧化-还原状态的改变,从而导致CPs的电荷量、掺杂水平、导电性以及体积发生变化.利用CPs的这些特性,可将其用于药物、蛋白质以及基因等的传递和可控释放.通过对CPs基体进行化学物理修饰,可以扩大CPs基体的载药品种、提高载药量以及优化药物控释手段.本文简要介绍了CPs的性能和制备方法,对CPs基药物传递体系的药物担载和释放机理进行了详细的讨论,并归纳总结了近年来国内外以CPs为基体的药物传递体系的研究进展,最后对CPs基药物传递体系所面临的问题和未来发展进行了总结和展望.     

用共轭亚油酸构筑层状液晶的药物传递系统

在水相中用共轭亚油酸(CLA)及其钠盐(SCL)构筑层状液晶相, 并考察了其药物缓释行为. 借助偏光显微镜并辅以目测确定CLA/SCL/H₂O三元相图中的层状液晶相区, 然后用偏光显微镜、 小角X射线散射仪和旋转流变仪获得层状液晶的偏光织构、 相参数和流变参数等, 证实其适用于药物传递系统(DDS). 采用透析法研究了负载亲水性药物5-氟尿嘧啶或亲油性药物姜黄素的层状液晶的释药曲线, 结果表明, 该类层状液晶对2种药物均有良好的缓释能力.     

抗癌中草药冬凌草甲素的吸附伏安行为

研究了抗癌药物冬凌草甲素在悬汞电极上的电化学行为。在NaAc NaOH(pH=7.8)的缓冲溶液中,冬凌草甲素有一受吸附控制的还原峰,峰电位为-1.150V,其电极反应过程是单电子转移,传递系数α为0.834,电荷传递表观速率常数KS为2.26s-1,初步探讨了其可能的电极反应机理.     

基于壳聚糖的纳米药物传递体系

壳聚糖作为天然高分子材料,不仅安全无毒、而且具有良好的生物相容性、可生物降解性等优点,在药物传递领域作为纳米载体倍受关注。壳聚糖基纳米载体材料制备条件简单温和,近年来,其相关研究也颇为新颖。本文以载体形成的驱动力作为切入点,从共价交联、离子相互作用、聚电解质络合物和疏水改性四个方面,总结不同种类壳聚糖基纳米载体的构筑方法,同时介绍该载体对药物传递中载药量、载药率、释放行为以及细胞毒性等方面的影响,在此基础上展望其未来的应用前景。     

含环糊精膜的制备与应用

本文简要介绍了环糊精的结构和性质,环糊精具有外部亲水,内部疏水的特殊分子构型,在膜内引入环糊精或环糊精衍生物对膜的性能具有很大的影响。综述了环糊精及其衍生物膜在异构体分离、金属离子传递、药物控制释放、药物检测与分析、酯盐水解及其他领域等方面的应用,评述了环糊精在自组装分子管道方面的作用,最后对含环糊精膜的发展方向进行了展望。     

核酸的有机化学研究在分子生物学发展中的作用

本文主要综述有机化学在建立核酸的顺序测定法和自动顺序仪,在破译遗传密码,在建立核酸片段的化学合成方法,固相合成法及DNA合成仪的设计,在合成许多有生物活力的核酸分子,在发展并完善遗传工程以及新近发现酶RNA(Ribozyme)等方面的卓越贡献。最后简要地展望有机化学将对生物学发展作出进一步贡献的几个方面。     

环取代基对金属化聚苯胺衍生物膜修饰电极性能的影响

通过比较聚2，5－二甲氧基苯胺（PDMAn）、聚邻甲基苯胺（POT）和聚间氯苯胺（PmClAn）膜修饰电极的氧化还原电位、沉积在这3种聚合物上的铂微粒的表面形态与晶面取向以及异丙醇在分散Pt微粒的聚苯胺膜修饰电极上的氧化行为，从电子效应和立体效应探讨了聚合物电化学性质与环取代基的关系以及不同聚合基质对Pt沉积机理和有催化性能的影响,结果表明，在硫酸溶液中PDMAn膜修饰电极的氧化还原电位最负、POT次之、PmClAn最正，Pt在PDMAn和POT膜上的电沉积机理与在PmClAn膜上的不同，聚合物膜上沉积的Pt微粒呈现（200)晶面择优取向，其中POT膜上择优取向度最大，PDMAn次之，Pm-ClAn最小，异丙醇在金属化聚合物膜电极上的氧化电位取决于聚苯胺的本质，在POT膜修饰电极上异丙醇的电氧化主要发生在POT的活性电位区，而在PDMAn与PmClAn膜上的电氧化则主要发生在Pt上的氧化电位区，说明聚合物膜不仅作为Pt微粒的分散介质，而且本身有产生催化作用。     

Growth and characterization of pyrene crystals on carbon nanofibers

Pyrene crystals were grown on carbon nanofibers (CNFs) by dispersing pyrene polycrystals and CNFs in water during ultrasonic irradiation, and they were characterized by scanning electron microscopy, X-ray diffractometry (XRD) and spectroscopy. The XRD measurements indicated that the orientation and size of the pyrene crystals on the CNF aggregates were different from that of the added pyrene polycrystals. Based on the spectroscopic properties of the pyrene crystals on the CNFs, the pyrene crystals on the CNF aggregates and on the individual CNFs were determined to be polycrystals and single crystals, respectively. These results indicate that pyrene crystals are produced on the CNFs by recrystallization of the added pyrene polycrystals and their crystal states depend on the aggregation state of the CNFs.     

Recent progress in experiments for sessile droplet wetting on structured surfaces

Wetting of a sessile droplet on structured or patterned surface can be found in a broad range of applications. The researchers have been promoted to keep working on the topic. The review is on the basis of the recent experimental advances on the sessile droplet wetting on the hydrophobic, hydrophilic, or combined hydrophobic and hydrophilic surfaces under isothermal conditions, and on heating or cooling substrates having nonisothermal conditions. More attention has been paid on the wetting configuration between the sessile droplet and the structured substrate; the research gap has been discussed on identifying the three-phase line shape. Further, the three-dimensional measurement for the sessile droplets on the patterned surfaces with focusing more on the contact line of sessile droplets might reveal new physical insights. This review targets at building a holistic overview on the sessile droplet wetting behaviors on the structured substrate in the past 2 years.     

化学发光酶免疫分析研究进展

叙述了化学发光免疫分析的分类及特点,从发光底物、增强剂、过氧化物酶、过氧化物及其他方面,对鲁米诺类化合物化学发光酶免疫分析的进展进行了综述,引用文献34篇。     

咪唑啉酰胺在电偶电极表面的吸附行为

采用原子力显微镜技术研究了有机阳离子缓蚀剂(咪唑啉酰胺)在电偶电极表面的吸附行为, 并探讨了其腐蚀抑制机理. 结果表明, 金属表面的过剩电荷较大地影响缓蚀剂分子的吸附行为. 在1%的NaCl溶液中, 碳钢电极表面带有过剩的负电荷；不锈钢电极表面带有过剩的正电荷；碳钢电极和不锈钢电极耦合后, 其表面分别带有过剩的正电荷和负电荷. 在耦合前阳离子缓蚀剂分子仅吸附在碳钢表面, 耦合后缓蚀剂分子在偶对的阴极(不锈钢)和阳极(碳钢)表面均有吸附, 但缓蚀剂分子在碳钢表面的吸附强度和覆盖度较之耦合前降低, 缓蚀剂的腐蚀抑制能力减弱.     

大孔吸附树脂对邻甲酚的吸附行为研究

研究了大孔吸附树脂NDA—909吸附水溶液中邻甲酚的热力学特征，并与Amberlite XAD—4树脂进行了比较．通过吸附动力学实验，初步探讨了初始温度对吸附过程的影响。结果表明，NDA—909对邻甲酚的吸附符合Freundlich经验公式，表现为放热的物理吸附过程．此外吸附速率受颗粒内扩散和其它类型扩散的共同控制。     

In Vitro Studies on Therapeutic Effects of Cannabidiol in Neural Cells: Neurons,Glia, and Neural Stem Cells

(‒)-Cannabidiol (CBD) is one of the major phytocannabinoids extracted from the Cannabis genus. Its non-psychoactiveness and therapeutic potential, partly along with some anecdotal—if not scientific or clinical—evidence on the prevention and treatment of neurological diseases, have led researchers to investigate the biochemical actions of CBD on neural cells. This review summarizes the previously reported mechanistic studies of the CBD actions on primary neural cells at the in vitro cell-culture level. The neural cells are classified into neurons, microglia, astrocytes, oligodendrocytes, and neural stem cells, and the CBD effects on each cell type are described. After brief introduction on CBD and in vitro studies of CBD actions on neural cells, the neuroprotective capability of CBD on primary neurons with the suggested operating actions is discussed, followed by the reported CBD actions on glia and the CBD-induced regeneration from neural stem cells. A summary section gives a general overview of the biochemical actions of CBD on neural cells, with a future perspective. This review will provide a basic and fundamental, but crucial, insight on the mechanistic understanding of CBD actions on neural cells in the brain, at the molecular level, and the therapeutic potential of CBD in the prevention and treatment of neurological diseases, although to date, there seem to have been relatively limited research activities and reports on the cell culture-level, in vitro studies of CBD effects on primary neural cells.     

Influence of Mg^2＋ on Initial Stages of CaCO3 Scale Formed on Metal Surface

Magnesium ions, which exist in formation water and injection water under downhole conditions in the oil and gas production industry, are a key determinant in the CaCO3 scale formation. Many studies have focused their attention on the effect of magnesium on the kinetics, the morphology and the content of Mg in the Ca-CO3 scale. Little attention has been paid to the effect of Mg^2 on the initial stages of CaCO3 formation on a metal surface. In this study, an electrochemical technique was used to study the influence of Mg^2 on the ini-tial stages of CaCO3 scale formed on a metal surface. With this electrochemical technique, the reduction of the dissolved oxygen in an analysis solution is considered on the surface of a rotating disk electrode (RDE) un-der potentiostatic control. The rate of oxygen reduction on the surface of the RDE enables the extent of sur-face coverage of scale to be assessed. With this electrochemical technique, a new insight into the effect of Mg^2 on CaCO3 scale formed on a metal surface is given.     

Influence of molecular order on the local work function of nanographene architectures: a Kelvin-probe force microscopy study.

We report a Kelvin-probe force microscopy (KPFM) investigation on the structural and electronic properties of different submicron-scale supramolecular architectures of a synthetic nanographene, including extended layers, percolated networks and broken patterns grown from solutions at surfaces. This study made it possible to determine the local work function (WF) of the different pi-conjugated nanostructures adsorbed on mica with a resolution below 10 nm and 0.05 eV. It revealed that the WF strongly depends on the local molecular order at the surface, in particular on the delocalization of electrons in the pi-states, on the molecular orientation at surfaces, on the molecular packing density, on the presence of defects in the film and on the different conformations of the aliphatic peripheral chains that might cover the conjugated core. These results were confirmed by comparing the KPFM-estimated local WF of layers supported on mica, where the molecules are preferentially packed edge-on on the substrate, with the ultraviolet photoelectron spectroscopy microscopically measured WF of layers adsorbed on graphite, where the molecules should tend to assemble face-on at the surface. It appears that local WF studies are of paramount importance for understanding the electronic properties of active organic nanostructures, being therefore fundamental for the building of high-performance organic electronic devices, including field-effect transistors, light-emitting diodes and solar cells.