A novel fluorescent aptasensor for thrombin detection: using poly(m-phenylenediamine) rods as an effective sensing platform

In this communication, we develop a novel fluorescent aptasensor for thrombin detection with the use of poly(m-phenylenediamine) (PMPD) rods as an effective sensing platform. This aptasensor exhibits extraordinarily high sensitivity with a detection limit as low as 100 pM and excellent selectivity.     

Preparation of Ag nanoparticle-decorated poly(m-phenylenediamine) microparticles and their application for hydrogen peroxide detection

The chemical oxidation polymerization of m-phenylenediamine (MPD) by ammonium persulfate (APS) at room temperature results in the formation of poly(m-phenylenediamine) (PMPD) microparticles. The subsequent treatment of such microparticles with an aqueous AgNO(3) solution produces Ag nanoparticle (AgNP)-decorated PMPD microparticles. It was found that as-formed AgNPs exhibited remarkable catalytic performance toward the reduction of hydrogen peroxide (H(2)O(2)). The enzymeless H(2)O(2) sensor constructed with such composites showed a fast amperometric response time of less than 5 s, and the corresponding linear range and detection limit were estimated to be from 0.1 to 30 mM and 4.7 μM, respectively, at a signal-to-noise ratio of 3.     

Strong deaggregating effect of a novel polyamino resorcinarene surfactant on gold nanoaggregates under microwave irradiation

Gold nanoparticles were prepared by ethylene glycol (EG) reducing gold chloride under microwave irradiation. The EG-stabilized gold colloids varied from red to blue with increasing amounts of EG, due to particle aggregation. Addition of the macrocyclic polyamine 2,8,14,20-tetranonyl-4,6,10,12,16,18,22,24-octa(1-aminoethylcarbamoyl)methoxyresorcinarene (TNMR) reversed nanoparticle aggregation under microwave irradiation and greatly improved their dispersion stability in aqueous solutions. These effects are likely due to the amphiphilic nature of TNMR, which has a large hydrophilic headgroup with eight amino groups and four hydrophobic chains. Moreover, the large and flexible hydrophilic groups containing more N and O atoms in the TNMR molecule has a strong stretching and penetrating ability in the aqueous solution, and TNMR molecules can easily form a bilayer protecting structure on the surface of gold nanoparticles, which plays a critical role in the color-change process of the EG-stabilized gold colloid.     

<Emphasis Type="Italic">N</Emphasis>-(4-(quinazolin-2-yl)phenyl)benzamide derivatives with potent anti-angiogenesis activities: synthesis and evaluation

Expanding our studies on the anti-angiogenesis activities of 2,4-disubstituted quinazoline derivatives [8], a series of novel N-(2-(quinazolin-2-yl)phenyl)benzamide (SZ) derivatives were designed and synthesized. Cytotoxicity assays indicated that most of these compounds displayed similar cytotoxicity against tumor cells in comparison with our previously reported, but showed a higher cytotoxicity against HUVECs. The SZ derivatives showed a remarkable inhibitive effect against the migration and adhesion of HUVECs, in addition to demonstrating significant in vivo anti-angiogenesis activities in the chick embryo chorioallantoic membrane (CAM) assay. The results proved that the introduction of an aryl group with a basic amide side chain on the 4′ position linked to the amide of the C-2 substituted quinazoline scaffold is an effective approach to improve the anti-angiogenic activity of quinazoline derivatives.     

Efficient synthesis of pentasubstituted pyrroles via one-pot reactions of arylamines,acetylenedicarboxylates, and 3-phenacylideneoxindoles

An efficient synthetic method for the pentasubstituted pyrroles was successfully developed via the one-pot domino reactions of arylamines, acetylenedicarboxylates, and 3-phenacylideneoxindoles. The reaction mechanism involved the sequential Michael addition and ring closure of the in situ generated β-active enamino ester.     

Electrowetting of aligned carbon nanotube films

Electrowetting is one approach to reducing the interfacial tension between a solid and a liquid. In this method, an electrical potential is applied across the solid/liquid interface which modifies the wetting properties of the liquid on the solid without changing the composition of the solid and liquid phases. Electrowetting of aligned carbon nanotube (CNT) films is investigated by the sessile drop method by dispensing deionized (DI) water or 0.03 M NaCl droplets (contacted by Au wire) onto aligned CNT films assembled on a copper substrate. The results demonstrate that electrowetting can greatly reduce the hydrophobicity of the aligned CNTs; the contact angle saturation for DI water and 0.03 M NaCl droplets occurs at 98 and 50 degrees , respectively. The combined effects of the geometrical roughness and the electrical potential on the contact angle are briefly discussed and modeled. Such a strategy may be invoked to controllably reduce the interfacial tension between carbon nanotubes (CNTs) and polymer precursors when infiltrating the monomers into the prealigned nanotube films.     

A dual-responsive superparamagnetic Fe3O4/Silica/PAH/PSS material used for controlled release of chemotherapeutic agent,keggin polyoxotungstate,PM–19

A bicontrollable drug release system was developed by layer-by-layer assembly of poly(allylamine hydrochloride) (PAH)/sodium poly(styrene sulfonate) (PSS) multilayers onto a Fe₃O₄/SiO₂ composite core. The saturated magnetization of this system reaches up to 38.6 emu/g at RT, making targeting easily controlled by an external magnetic field. Meanwhile, the packing of the polyelectrolyte multilayers is sensitive to pH values, generating a pH-switch on-off mode for the release of loaded drugs. In this specific case, the release of a chemotherapeutic polyoxometalate K₇Ti₂W₁₀PO₄₀·6H₂O (PM–19) was tested. Transmission electron microscopy (TEM) was used to examine the nanostructure of the composite drug release system. UV–vis absorption was used to monitor the drug release. Fourier transform infrared (FTIR), Powder X–ray diffraction, and Elemental analyses were used to study the composition of tested systems. The structure and composition of the composite system was also studied using magnetism measurement and nitrogen adsorption–desorption.     

Simple synthesis of zwitterionic diblock copolymers for the application on metal nanoparticles preparation

AB diblock copolymers of poly(2-(dimethylamino)ethyl metharylate-block-potassiurn acrylate) were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization. The structure of the block polymer was determined by the nuclear magnetic resonance (NMR) spectroscopy and the gel permeation chromatography. Moreover, it has also been shown that the diblock copolymers exhibit aggregate as function of the pH according to the result of ¹H-NMR spectroscopy, FT-IR absorption spectra, UV-vis transmittance spectroscopy, transmission electron microscopy and ultrasonic particle size analyzer. The result was attributed that such AB diblock copolymers were tailored to undergo pH-induced self-assembly. Furthermore, the aggregate can be as template of metal nanoparticles preparation, and the sizes of the aggregate, in turn, strongly control nanoparticle sizes.