In situ labeling and imaging of cellular protein via a bi-functional anticancer aptamer and its fluorescent ligand

In this article, we reported a novel approach for in situ labeling and imaging HeLa cancer cells utilizing a bifunctional aptamer (AS1411) and its fluorescent ligand, protoporphyrin IX (PPIX). In the presence of potassium ion, AS1411 folded to G-quadruplex structure, binded fluorescent ligand (PPIX) with fluorescent enhancement, and targeted the nucleolin overexpressed by cancer cells. Consequently, bioimaging of cancer cells specifically were realized by laser scanning confocal microscope. The bioimaging strategy with AS1411–PPIX complex was capable to distinguish HeLa cancer cells from normal cells unambiguously, and fluorescence imaging of cancer cells was also realized in human serum. Moreover, the bioimaging method was very facile, effective and need not any covalent modification. These results illustrated that the useful approach can provide a novel clue for bioimaging based on non-covalent bifunctional aptamer in clinic diagnosis.     

Two-dimensional photovoltaic copolymers with spatial D-A-D structures: synthesis,characterization and hetero-atom effect

A series of two-dimensional(2D)conjugated copolymers with spatial D-A-D structures(PTNBTB,PTCBTB,and PTSBTB)consisting of hetero-atom-bridged dithiophene and phenylvinyl-substituted benzothiadiazole blocks in the main chain have been designed,synthesized,and characterized.The structure-property relationships of the resulting copolymers were systematically investigated.The effects of the bridging atoms(N,C,and Si)on their thermal,optical,electrochemical and chargetransporting properties were also studied.PTNBTB exhibits a smaller band gap with red-shifted absorption,whereas PTSBTB possesses deeper HOMO level and higher hole mobility than PTCBTB or PTSBTB.Bulk heterojunction(BHJ)solar cells were fabricated and characterized with the conventional configuration of ITO/PEDOT:PSS/copolymer:PC71BM(1:1)/Ca/Al.As expected,PTSBTB devices showed the highest PCE,up to 4.01%,which was due to the lower HOMO level,higher carrier mobility,and stronger optical response as well as the finer nanoscale phase separation of the pristine polymer and/or the corresponding blending active layer with PC71BM.The primary results offer useful insights in designing 2D copolymers with spatial D-A-D backbone and different hetero-atom bridged donor units to finely tune the absorptions,electronic energy levels,carrier mobilities and the photovoltaic properties.     

Ultrasensitive colorimetric detection of protein by aptamer-Au nanoparticles conjugates based on a dot-blot assay

A simple, rapid and ultrasensitive colorimetric detection of protein using aptamer-Au nanoparticles (AuNPs) conjugates based on a dot-blot array has been developed, which was combined with the unique optical properties of AuNPs, enabling the visual detection of protein within minutes without any instrument.     

Core/shell microcapsules consisting of Fe3O4 microparticles coated with nitrogen-doped mesoporous carbon for voltammetric sensing of hydrogen peroxide

The authors describe the preparation of core/shell composites consisting of Fe₃O₄ microparticles coated with nitrogen-doped mesoporous carbon. Synthesis was accomplished by simultaneous reduction of template α-Fe₂O₃ and pyrolysis of a nitrogen-containing poly(ionic liquids). The mesoporous composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry and adsorption/desorption isotherms. The characterizations prove successful formation of an Fe₃O₄ core and an outer shell (coating) consisting of nitrogen-doped mesoporous carbon. The material was placed on a glassy carbon electrode and synergistic catalytic effect of of N-doping, the mesoporous, core/shell structure and two types of active sites properties between Fe₃O₄ core and nitrogen-doped mesoporous carbon shell is shown to result in superior electrochemical activity towards the reduction of hydrogen peroxide. Figures of merit include (a) a sensitivity of 77.1 μA mM⁻¹ cm⁻²; (b) a linear response over the 50 μM to 33 mM H₂O₂ concentration range, (c) a 5.9 μM detection limit of (at an S/N ratio of 3), and (d) a low working voltage of −0.4 V (vs. saturated calomel electrode) which makes the method more selective.

Electrochemical method for H₂O₂ detection based on Fe₃O₄@nitrogen-doped mesoporous carbon microcapsules core/shell composites (Fe₃O₄@NMCMs), prepared by the polymerization of the ionic liquids (1-Allyl-3-ethylimidazolium tetrafluoroborate, [AEIm]BF₄) monomer (PILs) on the surface of α-Fe₂O₃ nano-peanuts and then pyrolysis.

     

Side‐Chain Engineering of Benzodithiophene‐Fluorinated Quinoxaline Low‐Band‐Gap Co‐polymers for High‐Performance Polymer Solar Cells

A new series of donor–acceptor co‐polymers based on benzodithiophene and quinoxaline with various side chains have been developed for polymer solar cells. The effect of the degree of branching and dimensionality of the side chains were systematically investigated on the thermal stability, optical absorption, energy levels, molecular packing, and photovoltaic performance of the resulting co‐polymers. The results indicated that the linear and 2D conjugated side chains improved the thermal stabilities and optical absorptions. The introduction of alkylthienyl side chains could efficiently lower the energy levels compared with the alkoxyl‐substituted analogues, and the branched alkoxyl side chains could deepen the HOMO levels relative to the linear alkoxyl chains. The branched alkoxyl groups induced better lamellar‐like ordering, but poorer face‐to‐face packing behavior. The 2D conjugated side chains had a negative influence on the crystalline properties of the co‐polymers. The performance of the devices indicated that the branched alkoxyl side chains improved the V_oc, but decreased the J_sc and fill factor (FF). However, the 2D conjugated side chains would increase the V_oc, J_sc, and FF simultaneously. For the first time, our work provides insight into molecular design strategies through side‐chain engineering to achieve efficient polymer solar cells by considering both the degree of branching and dimensionality.     

固体火药的着火特性研究──激光点火实验

利用１０．６ｍ　ＣＯ＿２激光作热源，在常压下对不同的固体火药［黑火药，１１／７，６／７松樟（５％）（表面经松香障脑处理）及６／７松石（表面经松香石墨处理）］进行了点火试验，研究了发射药，特别是阻燃药的看火性能。实验中采用光电二极管和热电偶测量点火延迟时间及火药表面温度变化，结果令人满意。