A short and efficient synthesis of 1,5-anhydro-d-glucitol 6-phosphate

The important d-glucose and d-glucose 6-phosphate analogues 1,5-anhydro-d-glucitol and 1,5-anhydro-d-glucitol 6-phosphate were prepared from methyl-d-glucoside in high yield and purity. Protecting of the hydroxyl groups as their allyl ether followed by reductive cleavage of the glycosidic linkage with triethylsilane formed the protected anhydroglucitol. No ring rearrangement or ring contraction was observed during the reduction step. Using the PdCl₂-CuCl₂-activated charcoal system, the allyl ether bond was cleaved with a low loading of the catalyst (0.0025 equiv per allyl group). 1,5-Anhydro-d-glucitol 6-phosphate was prepared by the phosphylation of 1,5-anhydro-d-glucitol.     

Encapsulation of Photosensitizer into Multilayer Microcapsules by Combination of Spontaneous Deposition and Heat‐Induced Shrinkage for Photodynamic Therapy

Annealing of PDADMAC/PSS multilayer microcapsules assembled on PSS‐doped CaCO₃ particles at 80 °C for 30 min reduces their size dramatically from 6.9 ± 0.3 to 3.1 ± 0.5 µm. Methylene blue molecules are encapsulated by spontaneous deposition and post‐annealing with a concentration of 22 mg · mL^?1, which is 1000 times higher than the feeding value. The unreleased MB molecules are retained stably for a long time, which are then protected by the capsules against reductive enzymes and keep their photodynamic activity. The viability of HeLa cells incubated with the MB‐loaded capsules decreases sharply from ≈75 (dark cytotoxicity) to ≈20% after irradiation with a laser at 671 nm and 60 J · cm^?2 for 75 s.

     

Cellular Uptake of Covalent Poly(allylamine hydrochloride) Microcapsules and Its Influences on Cell Functions

The mechanism of the cellular uptake of polyelectrolyte microcapsules and its influences on the functions and toxicity of human SMCs are explored. The covalently assembled poly(allylamine hydrochloride)/glutaraldehyde microcapsules are easily ingested by SMCs mainly through macropinosis and caveolae‐mediated endocytosis pathways. The capsules mainly disperse in cytoplasm without colocalization in early endosomes and cell nucleus. The results of gene chips reveal substantial and profound alternation of cell phenotypes and functions. Uptake of the microcapsules cause a slight decrease of cell viability, but leads to significant changes in cytoskeleton organization, cell cycle, as well as cell adhesion and migration ability.

     

聚合物纳米粒子的结构和性能对胞吞和细胞功能的影响

随着纳米医学的发展,越来越多的聚合物纳米粒子被用作荧光探针和药物或基因的载体,在生物分析、检测以及药物传输和基因治疗等领域得到应用。细胞的胞吞是细胞将细胞外基质、病毒、微组织或纳米粒子运送到细胞内部的一个重要生理过程。研究细胞对纳米粒子的胞吞,有助于从细胞层次上理解生命现象,掌握细胞内治疗的机理。本文综述了近几年来细胞和聚合物纳米粒子之间相互作用的最新研究结果。首先介绍了用于胞吞研究的常用聚合物纳米粒子体系及其功能化方法,尤其是荧光探针的复合与表面修饰。进而介绍了细胞和聚合物纳米粒子之间相互作用的基本过程,包括聚合物纳米粒子在细胞转运过程中的驱动力、细胞内转运过程、在细胞中的分布及其细胞毒性。对影响聚合物纳米微粒胞吞的因素如纳米粒子浓度、共培养时间、纳米粒子性能（形状、粒径、电荷和PEG修饰）、细胞类型和培养条件等进行了总结。最后重点介绍了用于受体介导细胞胞吞的聚合物纳米粒子体系,指出了目前研究工作中的不足及未来发展方向。     

Printing biomacromolecules on a bovine serum albumin precursor layer

Various biomacromolecules including proteins and polysaccharides are printed on a substrate capped with a bovine serum albumin (BSA) precursor layer to create clear co-patterns of these molecules. Characterizations by confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) demonstrate the successful production and clear boundaries of the co-patterns. Rinsing the BSA-adsorbed substrate and the biomacromolecules-inked stamp before microcontact printing (microCP) is crucial for the creation of clear and stable co-patterns. The patterns are mainly stabilized by electrostatic interactions and van der Waals forces. Characterizations by ellipsometry, UV-Vis and fluorescence spectroscopy reveal that printing by a flat PDMS stamp yields a denser layered structure of proteins with a higher amount than that of adsorbed proteins. By printing, however, a lower enzymatic catalytic activity for horseradish peroxidase (HRP) or binding capability for avidin (both normalized to amount) is determined. A conformational transition from alpha-helix to beta-sheet of HRP is observed by ATR-IR. By contrast, a BSA precursor layer can effectively improve the functionality of the printed HRP or avidin and preserve the original conformation of the proteins, although the absolute transferred amount of these proteins is decreased.     

New existence results of positive solution for a class of nonlinear fractional differential equations

In this article, the existence and uniqueness of positive solution for a class of nonlinear fractional differential equations is proved by constructing the upper and lower control functions of the nonlinear term without any monotone requirement. Our main method to the problem is the method of upper and lower solutions and Schauder fixed point theorem. Finally, we give an example to illuminate our results.     

原位凝聚法制备聚电解质微胶囊——模板中掺杂聚电解质量对微胶囊结构与性能的影响

通过在CaCO3制备过程中加入不同浓度聚苯乙烯磺酸钠(PSS)的方法来控制掺杂进CaCO3粒子中的PSS含量,得到了PSS掺杂量为4%～11%,尺寸均匀的CaCO3球形微粒.在微粒表面仅吸附一层聚烯丙基胺盐酸盐(PAH)后,用乙二胺四乙酸二钠(EDTA)使碳酸钙溶解;释放出的PSS与PAH原位凝聚制备得到了分散良好且完整的聚电解质复合物微胶囊.在所研究的范围内,模板微粒中PSS的含量对微胶囊的形态结构和性能没有明显影响.与传统的层层组装微胶囊相比,聚电解质复合物微胶囊有较好的热稳定性,但在高盐浓度下尺寸收缩程度较大.由于和层层组装微胶囊相比缺乏结合紧密的有序结构,原位凝聚法制备的微胶囊囊壁的截留分子量较大.