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ABSTRACT: The bioresponsive detection of DNA or proteins and the controlled release of drug molecules are two important research areas for both experimental studies and practical applications. However, the real incorporation of these two functions into one system is still untouched. Being different from the widely reported mesoporous silica nanoparticles that were used as the support, herein we report a smart system based on hybrid phosphonate-TiO(2) mesoporous nanostructures capped with fluorescein labeled oligonucleotides, which can realize simultaneous and highly-efficient biomolecule sensing and controlled drug release. The fluorescence of the labeled oligonucleotides is first quenched by the phosphonate-TiO(2) materials, which are related to the fluorescence resonance energy transfer mechanism. The addition of complementary DNA strands or protein target leads to the displacement of the capped DNA due to hybridization or protein-aptamer reactions. The opening of the pores can further cause the release of entrapped drugs as well as the restoration of dye fluorescence. The present method is proven to have high selectivity towards specific ssDNA and proteins.
The Analyst 01/2013; · 4.23 Impact Factor
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ABSTRACT: A novel and simple method for the preparation of silica nanoparticles having surface-functionalized diamino moiety (dASNPs) was reported in our paper and characterized using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, and thermogravimetry techniques. To test this method practically, in this contribution we describe the enhanced separation of four plant auxins - indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), 2,4-dichlorophenoxyacetic acid (dCPAA), and 2-(1-naphthyl) acetic acid (NAA) - by capillary electrochromatography using diamino moiety functionalized silica nanoparticles as pseudostationary phase (PSP) in the running buffer. The effect of pH, buffer concentration, and diamino moiety functionalized silica nanoparticles concentration on the selectivity of separation was investigated. A combination of the nanoparticles and running buffer reversed the electroosmotic direction making possible the rapid and efficient separation of the auxins from the auxins migrated in the same direction with the EOF under optimum experimental conditions. A good resolution of four auxins was obtained within 5.5 min under optimum experimental conditions. The precision (RSD, n = 5) was in the range of 0.72-0.91% and 1.89-2.23% for migration time and peak area response, respectively. The detection limits were 0.48, 0.44, 0.46, and 0.42 μM for NAA, IBA, IAA, and dCPAA, respectively. Furthermore, the method was successfully tested for the determination of IAA in the grapes.
Electrophoresis 07/2012; 33(13):2012-8. · 3.30 Impact Factor
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ABSTRACT: A kind of novel amphiphilic silica-based nanoparticle having surface-bound octanoyl-aminopropyl moieties (OA-NP) with the diameter of ~250 nm was successfully prepared and characterized by elemental analysis, Fourier transform infrared spectrometry. The potential use of OA-NP as pseudostationary phase in capillary electrochromatography for the separation of aromatic acids, basic, and neutral compounds was investigated. Five aromatic acids were separated rapidly with high column efficiency as they migrate in the same direction with the EOF under optimum experimental conditions. Under a running buffer with the composition of 40% methanol, 10 mM phosphate buffer (pH 5.5) with 1.0 mg/mL OA-NPs added, basic compounds investigated were baseline resolved with relatively symmetrical peaks. Due to the existence of polar acyl amide group on the surface of OA-NPs, "silanol effect" that occurs between the positively charged basic analytes and the silanols of the capillary column was greatly suppressed. Furthermore, the newly synthesized OA-NPs were also tried for the separation of some neutral analytes, and satisfactory separations were obtained.
Electrophoresis 06/2011; 32(11):1357-63. · 3.30 Impact Factor
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ABSTRACT: Ordered, hexagonal, mesoporous metal (Ti, Zr, V, Al)-phosphonate materials with microporous crystalline walls are synthesized through a microwave-assisted procedure by using triblock copolymer F127 as the template. Corresponding metal chlorides and ethylene diamine tetra(methylene phosphonic acid) are chosen as the inorganic precursors and the coupling molecule, respectively. X-ray diffractometry, transmission electron microscopy, N(2) sorption, and thermogravimetry measurements confirm that the obtained metal phosphonates possess a hierarchically porous structure with pore sizes of 7.1-7.5 nm and 1.3-1.7 nm for mesopores and micropores, respectively, and the metal phosphonate materials are thermally stable up to around 450 °C with the pore structure and hybrid framework well preserved. Magic angle spinning NMR, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses indicate that the phosphonate groups are homogenously incorporated into the hybrid framework of the obtained materials. For the first time, the mesoporous hybrid materials are employed as the stationary phase in open tubular capillary electrochromatography technique for the separation of various substances including acidic, basic, and neutral compounds. These materials show good selectivity and reproducibility for this application.
Small 05/2011; 7(13):1827-37. · 8.35 Impact Factor
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ABSTRACT: Amphiphilic silica nanoparticles surface-functionalized by 3-aminopropyltriethoxysilane (APTES) and octyltriethoxylsilane (OTES) were successfully prepared and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR) and thermogravimetry (TG) techniques. The potential use of these bifunctionalized nanoparticles as pseudostationary phases (PSPs) in capillary electrophoresis (CE) for the separation of charged and neutral compounds was evaluated in terms of their suitability. As expected, fast separation of representative aromatic acids was fulfilled with high separation efficiency, because they migrate in the same direction with the electroosmotic flow (EOF) under optimum experimental conditions. Using a buffer solution of 30mmol/L phosphate (pH 3.0) in the presence of 0.5mg/mL of the synthesized bifunctionalized nanoparticles, the investigated basic compounds were baseline-resolved with symmetrical peaks. Due to the existence of amino groups on the surface of nanoparticles, "silanol effect" that occurs between positively charged basic analytes and the silanols on the inner surface of capillary was greatly suppressed. Furthermore, the separation systems also exhibited reversed-phase (RP) behavior when neutral analytes were tested.
Journal of chromatography. A 10/2010; 1217(47):7448-54. · 4.19 Impact Factor
