Fabrication of MPEG-b-PMAA capped YVO4:Eu nanoparticles with biocompatibility for cell imaging.

A novel nanoparticle with multilayer core-shell architecture for cell imaging is designed and synthesized by coating a fluorescent YVO4:Eu core with a diblock copolymer, MPEG-b-PMAA. The synthesis of YVO4:Eu core, which further makes MPEG-b-PMAA-YVO4:Eu NPs adapt for cell imaging, is guided by the model determined upon the evaluation of pH and CEu%. The PMAA block attached tightly on the YVO4:Eu core forms the inner shell and the MPEG block forms the biocompatible outermost shell. Factors including reaction time, reaction temperature, CEu% and pH are optimized for the preparation of the YVO4:Eu NPs. A precise defined model is established according to analyzing the coefficients of pH and CEu% during the synthesis. The MPEG-b-PMAA-YVO4:Eu NPs, with an average diameter of 24 nm, have a tetragonal structure and demonstrate luminescence in the red region, which lies in a biological window (optical imaging). Significant enhancement in luminescence intensity by MPEG-b-PMAA-YVO4:Eu NPs formation is observed. The capping copolymer MPEG-b-PMAA improves the dispersibility of hydrophobic YVO4:Eu NPs in water, making the NPs stable under different conditions. In addition, the biocompatibility MPEG layer reduces the cytotoxicity of the nanoparticles effectively. 95% cell viability can be achieved at the NPs concentration of 800 mgL(-1) after 24h of culture. Cellular uptake of the MPEG-b-PMAA-YVO4:Eu NPs is evaluated by cell imaging assay, indicating that the NPs can be taken up rapidly and largely by cancerous or non-cancerous cells through an endocytosis mechanism.

Facile synthesis of multifunctional multi-walled carbon nanotube for pathogen Vibrio alginolyticus detection in fishery and environmental samples.

Interest in carbon nanotubes for detecting the presence of pathogens arises because of developments in chemical vapor deposition synthesis and progresses in biomolecular modification. Here we reported the facile synthesis of multi-walled carbon nanotubes (MWCNTs), which functioned as immuno-, magnetic, fluorescent sensors in detecting Vibrio alginolyticus (Va). The structures and properties of functionalized MWCNTs were characterized by ultraviolet (UV), Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), magnetic property measurement system (MPMS) and fluorescent spectra (FL). It was found that the functionalized MWCNTs showed: (1) low nonspecific adsorption for antibody-antigen, (2) strong interaction with antibody, and (3) high immune-magnetic activity for pathogenic cells. Further investigations revealed a strong positive linear relationship (R=0.9912) between the fluorescence intensity and the concentration of Va in the range of 9.0 × 10(2) to 1.5 × 10(6) cfum L(-1). Moreover, the relative standard deviation for 11 replicate detections of 1.0 × 10(4) cfum L(-1) Va was 2.4%, and no cross-reaction with the other four strains was found, indicating a good specificity for Va detection. These results demonstrated the remarkable advantages of the multifunctional MWCNTs, which offer great potential for the rapid, sensitive and quantitative detection of Va in fishery and environmental samples.

N-(Naphthalen-1-yl-methyl-idene)-4H-1,2,4-triazol-4-amine.

In the title mol-ecule, C(13)H(10)N(4), the dihedral angle between the triazole ring and the naphthalene ring system is is 56.1 (2)°. In the crystal, mol-ecules are connected by weak C-H⋯N hydrogen bonds into chains along [100]. A short intra-molecular C-H⋯N contact is also observed.

The triclinic form of di-µ-aqua-bis-[diaqua-bis-(thio-cyanato-κN)iron(II)]-1,4-bis-(4H-1,2,4-triazol-4-yl)benzene (1/3).

In the title compound, [Fe(2)(NCS)(4)(H(2)O)(6)]·3C(10)H(8)N(6), the centrosymmetric dinuclear complex contains two Fe(II) ions bridged by two aqua ligand O atoms, forming a four-membered ring. The slightly distorted octa-hedral coordination environment of the two Fe(II) ions is completed by two monodentate aqua ligands and two thio-cyanate ligands. One of the 1,4-bis-(4H-1,2,4-triazol-4-yl)benzene mol-ecules lies across an inversion center. In the crystal, O-H⋯N hydrogen bonds connect the components, forming a two-dimensional network parallel to (011). In addition, π-π stacking inter-actions involving the benzene and triazole rings, with centroid-centroid distances in the range 3.502 (5)-3.787 (6) Å, connect the two-dimensional hydrogen-bonded network into a three-dimensional network.

1,4-Bis(4H-1,2,4-triazol-4-yl)benzene dihydrate.

The asymmetric unit of the title compound, C(10)H(8)N(6)·2H(2)O, comprises half the organic species, the mol-ecule being completed by inversion symmetry, and one water mol-ecule. The dihedral angle between the 1,2,4-triazole ring and the central benzene ring is 32.2 (2)°. The water mol-ecules form O-H⋯N hydrogen bonds with N-atom acceptors of the triazole rings. C-H⋯N hydrogen bonds are also observed, giving a three-dimensional framework.