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ABSTRACT: Here we report that branch poly(ethylenimine) (BPEI) could be used as both a stabilizer and a reducing agent in the preparation of long-term stable polycations-functionalized graphene nanosheets (GNs) suspension with concentration as high as 5 mg mL(-1). UV-vis spectroscopy, Fourier transform infrared, X-ray photo-electron spectroscopy, atomic force microscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction were used to characterize the reduction process, composition and structure of BPEI functionalized GNs (BGNs). Fourier transform infrared and X-ray photo-electron spectroscopy data revealed that the BPEI was attached to the surface of GNs through covalent bonds such as amide bond and -Ar-NH-C bond, and could prevent their aggregation through strong electrostatic repulsion. From the atomic force microscopy image and height profile of BGNs, the modality of functionalized surface of BGNs should be continuous and compact. The as-obtained BGNs could disperse well not only in water but also in other alkaline solution, salt solution and organic solvents. The as-obtained BGNs containing abundant amino groups were used as effective and controllable templates for fast and facile assembly with a series of negatively charged nanoparticles (NPs), which was probably caused by the strong electrostatic interaction between both components. This paper presents a fast, facile, controllable, efficient and green approach for preparing GNs and GNs/NPs composites of great value for applications in various fields.
Nanoscale 12/2012; · 5.91 Impact Factor
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ABSTRACT: A new kind of silver micro-dendrites have been synthesized for the separation and multiplex detection of DNA merely by earth gravity. Through this approach, the DNA strands of the sickle cell disease, human T-lymphotropic virus type I, the anthrax lethal factor can be detected down to 100 pM with the detection range from 100 pM to 100 nM at the same time.
Chemical Communications 04/2011; 47(38):10581-3. · 6.17 Impact Factor
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ABSTRACT: A new kind of silver micro-dendrites with no surfactants protected has been synthesized for the separation and detection of DNA merely by earth gravity as the density of silver is larger than that of water. Through this approach, the DNA of human T-lymphotropic virus type I (HTLV-I) can be detected down to 10 pM with the detection range from 10 pM to 100 nM.
Chemical Communications 12/2010; 46(46):8818-20. · 6.17 Impact Factor
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ABSTRACT: Among the functional nucleic acids studied, adenine-rich nucleic acids have attracted attention due to their critical roles in many biological processes and self-assembly-based nanomaterials, especially deoxyribonucleic acids (abbreviated as poly(dA)). Therefore the ligands binding to poly(dA) might serve as potential therapeutic agents. Coralyne, a kind of planar alkaloid, has been firstly found that it could bind strongly to poly(dA). This work herein reports an approach for visual sensing of the coralyne-poly(dA) interaction. This method was based on the coralyne inducing poly(dA) into the homo-adenine DNA duplex and the difference in electrostatic affinity between single-stranded DNA and double-stranded DNA with gold nanoparticles (GNPs). Furthermore, we applied the recognition process of the interaction between coralyne and poly(dA) into specific coralyne detection with the assistance of certain software (such as Photoshop). A linear response from 0 to 728 nM was obtained for coralyne, and a detection limit of 91 nM was achieved.
The Analyst 08/2009; 134(8):1647-51. · 4.23 Impact Factor
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ABSTRACT: A novel [Ru(bpy)(2)(dcbpy)NHS] labeling/aptamer-based biosensor combined with gold nanoparticle amplification for the determination of lysozyme with an electrochemiluminescence (ECL) method is presented. In this work, an aptamer, an ECL probe, gold nanoparticle amplification, and competition assay are the main protocols employed in ECL detection. With all the protocols used, an original biosensor coupled with an aptamer and [Ru(bpy)(2)(dcbpy)NHS] has been prepared. Its high selectivity and sensitivity are the main advantages over other traditional [Ru(bpy)(3)](2+) biosensors. The electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) characterization illustrate that this biosensor is fabricated successfully. Finally, the biosensor was applied to a displacement assay in different concentrations of lysozyme solution, and an ultrasensitive ECL signal was obtained. The ECL intensity decreased proportionally to the lysozyme concentration over the range 1.0x10(-13)-1.0x10(-8) mol L(-1) with a detection limit of 1.0x10(-13) mol L(-1). This strategy for the aptasensor opens a rapid, selective, and sensitive route for the detection of lysozyme and potentially other proteins.
Chemistry - An Asian Journal 10/2008; 3(11):1935-41. · 4.50 Impact Factor
