纳米二氧化硅粒子的制备及对BSA结构的影响

在碱性条件下水解正硅酸乙酯(TEOS)制备纳米二氧化硅(SiO_2)粒子,并采用同步荧光光谱和紫外可见分光光度法探讨了SiO_2对牛血清白蛋白(Bovine Serum Albumin,BSA)结构的影响。结果显示,SiO_2纳米粒子对BSA的结构没有发生显著的影响,这说明在实验条件下,SiO_2不会改变BSA分子的结构和微环境。     

电纺纤维在超级电容器中的应用

对高性能超级电容器不断增长的需求促进了电极隔膜和电极材料的快速发展。静电纺丝法制备的纳米纤维具有较高的孔隙率、较好电化学活性、较大的表面积以及良好的结构稳定性等优点,已被广泛应用于超级电容器的隔膜和电极材料。本文简要综述了近年来电纺纳米纤维在超级电容器用隔膜和电极材料的研究进展;着重讨论了通过静电纺丝和其他后处理方法制备的碳基纳米纤维、碳基复合纳米纤维、导电聚合物基复合纳米纤维和金属氧化物纳米纤维等用于超级电容器的电极材料。研究表明,多孔结构的构建、活化处理以及杂原子掺杂可以提高碳纳米纤维的比表面积、电化学活性、润湿性和石墨化程度,从而增强其电化学性能。此外,通过共混、化学沉积和电化学沉积等方法,将碳纳米纤维与金属氧化物、导电聚合物结合,可以改善其电容、倍率性能和循环稳定性。最后,提出上述研究中存在的问题,并对未来静电纺丝纳米纤维材料在超级电容器的发展前景进行了展望。     

Protease-responsive mass barcoded nanotranslators for simultaneously quantifying the intracellular activity of cascaded caspases in apoptosis pathways

Quantitatively delineating the activation network of multiple proteases that participate in cellular processes is highly essential for understanding the physiological and pathological states of cells. In this study, protease-responsive mass barcoded nanotranslators (PRMNTs) were engineered for revealing the activity of cascaded caspases in apoptosis in a multiplex and quantitative manner. In the PRMNTs, a series of mass tag-decorated gold nanoparticles (AuNPs) were tethered onto magnetic Fe₃O₄ nanospheres via a linker containing the substrate peptide of the target protease to form a “one-to-many” core–satellite structure. This nanostructure was internalized into the cells, underwent an enzymatic reaction within the cells, and allowed post-reaction mass spectrometry (MS) interrogation after magnetic separation from the cells. In the presence of intracellular caspases, enzymatic cleavage of the linker could be translated to the decreased ion signals of the mass tags on the remaining AuNPs in the PRMNTs by MS decoding. Benefiting from the multiplexing capability of MS, the intracellular activity of caspase-3, -8 and -9 that orchestrate the apoptotic process was simultaneously quantified at any given time. Kinetic analysis of caspase activity under stimulation of diverse anticancer drugs revealed that programmed cell death followed individual apoptosis pathways, differing in the activation degree and sequence of the caspase cascade. This work represents a modality that interfaces nanotechnology with MS for quantitatively probing the intracellular activity of multiple proteases, which opens up new avenues for revealing the apoptosis mechanism and developing innovative drugs.

Protease-responsive mass barcoded nanotranslators (PRMNTs) were engineered for revealing the apoptosis pathways by MS-based multiplex quantification of the intracellular activity of cascaded caspases.     

A simple and sensitive assay for apurinic/apyrimidinic endonuclease 1activity based on host-guest interaction of β-cyclodextrin polymer and pyrene

A simple and sensitive method for APE1 activity detection was developed based on fluorescence enhancement of pyrene in the presence of β-cyclodextrin polymer.     

Effect of mesopores on solidification of sirolimus self-microemulsifying drug delivery system

The mesoporous silica materials had a high loading efficiency of sirolimus-SMEDDS. The length of the mesopores played a more important role than the pore diameter in drug dissolution and in vivo absorption.     

Sequential protocol for C(sp)–H carboxylation with CO<Subscript>2</Subscript>: KO<Superscript><Emphasis Type="Italic">t</Emphasis></Superscript>Bu-catalyzed C(sp)–H silylation and KO<Superscript><Emphasis Type="Italic">t</Emphasis></Superscript>Bu-mediated carboxylation

CO₂ incorporation into C–H bonds is an important and interesting topic. Herein a sequential protocol for C(sp)–H carboxylation by employing a metal-free C–H activation/catalytic silylation reaction in conjunction with KO^tBu-mediated carboxylation with CO₂ was established, in which KO^tBu catalyzes silylation of terminal alkynes to form alkynylsilanes at low temperature, and simultaneously mediates carboxylation of the alkynesilanes with atmospheric CO₂. Importantly, the carboxylation further promotes the silylation, which makes the whole reaction proceed very rapidly. Moreover, this methodology is simple and scalable, which is characterized by short reaction time, wide substrate scope, excellent functional-group tolerance and mild reaction conditions, affording a range of corresponding propiolic acid products in excellent yields in most cases. In addition, it also allows for a convenient ¹³C-labeling through the use of ¹³CO₂.     

Cell alignment guided by nano/micro oriented collagen fibers and the synergistic vascularization for nervous cell functional expression

The majority of tissues within human body are constituted of designated structures to enable specific functions. Much effort has been done to engineer artificial fabric cell-laden scaffolds which are widely used for a great diversity of linear tissue constructs. For this purpose, collagen microfibers are of great concern among diverse materials while the control of cell-laden fiber formation and orientated structure is still unsolvable. Here, we developed a novel microfluidic-based strategy for continuous fabrication and assembly of three-dimensional (3D) cell-laden oriented collagen hydrogel microfibers. Inspired by the flow-introduced shear force in a microfluidic chip, collagen hydrogel microfibers obtained the oriented fabric structure which could guide rat pheochromocytoma cells (PC12) oriented spreading and enhance relative cellular functional expression. Rat aortic endothelial cells (RAOECs) were introduced to construct a co-cultured microfiber model, which further facilitated the functional expression of neural cells due to the synergistic effect of both vascularized-like cells and neural-like cells. Moreover, the ability of assembling collagen microfibers into larger constructs will benefit a variety of applications in tissue engineering and biomedical research.     

Nmp-based ionic liquids: Recyclable catalysts for both hetero-Michael addition and Knoevenagel condensation in water

A series of novel N-methyl piperidine (Nmp)-based ionic liquids with 1,2-propanediol group are synthesized and used as catalysts for both hetero-Michael addition of α,β-unsaturated amides and Knoevenagel condensation at room temperature in water; and all the examined substrates could be transformed into corresponding products in good to excellent yields. Meanwhile IL-catalyzed hetero-Michael addition of α,β-unsaturated amides in water has not been reported in the previous literatures. Additionally, the catalyst is recyclable for the two reactions. This finding provides a green catalyst for both hetero-Michael addition of α,β-unsaturated amides and Knoevenagel condensation in water.     

冬虫夏草中8种矿物元素含量分析

利用火焰原子吸收光谱法(FAAS),测定了冬虫夏草中Cu,Zn,Fe,Mn,Mg,Ca,Co以及Cd等8种矿物元素的含量,测定了各元素的加标回收率在98.9%~109.3%之间,相对标准偏差(RSD)小于1.2%,具有良好的准确度和精确度。结果表明,冬虫夏草中含有丰富的Cu,Zn,Fe,Mn,Mg,Ca,Co等多种矿物元素,不含有毒金属元素Cd。     

蛋白质分子荧光探针研究及其应用新进展

人体中多达10万种以上的蛋白质结构,功能千差万别,形成了生命的多样性和复杂性。在分子水平上分析和识别蛋白质对生命科学研究具有重要的理论和实践意义。本文综述了各种蛋白质分子荧光探针在蛋白质分析方面的应用,并展望了此类荧光探针的发展趋势和应用前景。引用文献60篇。