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ABSTRACT: Carbon-based "quantum" dots or carbon dots are surface-functionalized small carbon nanoparticles. For bright fluorescence emissions, the carbon nanoparticles may be surface-doped with an inorganic salt and then the same organic functionalization. In this study, carbon dots without and with the ZnS doping were prepared, followed by gel-column fractionation to harvest dots of 40% and 60% in fluorescence quantum yields, respectively. These highly fluorescent carbon dots were evaluated for optical imaging in mice, from which bright fluorescence images were obtained. Of particular interest was the observed competitive performance of the carbon dots in vivo to that of the well-established CdSe/ZnS QDs. The results suggest that carbon dots may be further developed into a new class of high-performance yet nontoxic contrast agents for optical bioimaging.
Theranostics. 01/2012; 2(3):295-301.
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ABSTRACT: Nanoscale carbon particles have emerged as versatile precursors for a new class of highly fluorescent nanomaterials that resemble semiconductor quantum dots. The surface-passivated fluorescent carbon nanoparticles, dubbed 'carbon dots', were already demonstrated for their potential optical bioimaging applications in vitro and in vivo. In this study, we conducted a systematic cytotoxicity evaluation on the carbon dots prepared by various combinations of precursor carbon nanoparticles and molecules for the particle surface functionalization. The results suggested that the cytotoxicity of carbon dots was dependent on the selection of surface passivation molecules. Those dots showing more significant cytotoxicity at higher concentrations were also evaluated for their effects on the fluorescence imaging of live cells. The implications of the results on the eventual use of carbon dots as cell imaging agents are discussed.
Experimental Biology and Medicine 11/2011; 236(11):1231-8. · 2.64 Impact Factor
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ABSTRACT: Inhibitory effects of the Noble muscadine grape extracts and the representative phytochemicals for anthocyanins (i.e., cyanidin and cyanidin-3,5-diglucoside) on two enzymes, that is, α-glucosidase and pancreatic lipase, were investigated regarding their antidiabetic activities. The study demonstrated that the anthocyanin extracts and the selected chemicals obeyed the competitive mode against the enzymes. The methanolic extracts of whole fruit and skin of the muscadine showed inhibitory activities against the α-glucosidase with their IC(50) values at 1.50 and 2.73 mg/mL, and those against the lipase at 16.90 and 11.15 mg/mL, respectively, which indicated that the muscadine extracts possessed strong antidiabetic activities. Particularly, the ethyl acetate (EtoAc) extract and the butanol (BuOH) extract exhibited much higher inhibitory activities against both enzymes than the CHCl(3) and water extracts, while the majority of anthocyanins existed in the BuOH fractions. Moreover, cyanidin exhibited a much stronger antidiabetic activity than cyanidin-3,5-diglucoside, suggesting that anthocyanins may have higher inhibitory activities after being digested. Further chromatographic analysis by high-performance liquid chromatography-mass spectrometry identified five individual anthocyanins, including cyanidin, delphinidin, petunidin, peonidin, and malvidin glycosides.
Journal of Agricultural and Food Chemistry 08/2011; 59(17):9506-11. · 2.82 Impact Factor
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Jia-Hui Liu,
Li Cao, Pengju G Luo,
Sheng-Tao Yang,
Fushen Lu,
Haifang Wang,
Mohammed J Meziani,
Sk Anwarul Haque,
Yuanfang Liu,
Sebastian Lacher,
Ya-Ping Sun
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ABSTRACT: The conjugation of fullerene with well-established drug molecules has been a representative strategy to impart fullerene-specific properties for improved formulation. However, conjugates involving fullerenes or other nanomaterials often differ significantly from the free drug molecules in cellular uptake and distributions. For the highly effective anticancer drug doxorubicin (DOX), its strong absorption and fluorescence in the visible spectral region enable the tracking of DOX-containing conjugates by optical techniques. In this work, a stoimetrically and structurally well-defined fullerene-DOX conjugate was studied in terms of fluorescence microscopy, including the fluorescence imaging with two-photon excitation, to examine the uptake and distribution in human breast cancer cells. The results suggested that the conjugate was distributed mostly in the cytoplasm, significantly different from free DOX molecules (predominantly in the cell nucleus, as already reported in the literature). Mechanistic implications of the results are discussed. Also discussed are potentials of conjugated DOX species as self-labeled fluorescent probes in bioimaging and other mechanistic investigations on drug delivery.
ACS Applied Materials & Interfaces 05/2010; 2(5):1384-9. · 4.53 Impact Factor
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ABSTRACT: It was reported previously that monosaccharide-functionalized single-walled carbon nanotubes (SWNTs) could interact with Bacillus anthracis (Sterne) spores with the mediation of a divalent cation such as Ca(2+) to result in significant spore aggregation and reduction in colony forming units. In this work a more systematic investigation was performed on interactions of the SWNTs functionalized with individual mannose and galactose moieties and their various dendritic configurations with B. anthracis and B. subtilis spores in the presence and absence of a divalent cation. Significant differences and selectivity between the Bacillus spores and between different sugars and their configurations were observed. The relevant results are presented, and their mechanistic implications are discussed.
ACS Nano 11/2009; 3(12):3909-16. · 10.77 Impact Factor
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ABSTRACT: Covalent conjugates of fullerene C(60) and the highly effective anticancer drug doxorubicin (DOX) were prepared and studied. The conjugation was through the amide linkage to preserve the intrinsic properties of DOX and fullerene cage. As designed, the conjugates with hydrophilic ethylene glycol spacers exhibited much improved aqueous compatibility, with significant solubility in water-DMSO mixtures. The anti-neoplastic activities of DOX were apparently unaffected in the conjugates according to evaluations in vitro with a human breast cancer cell line.
The Journal of Physical Chemistry C 10/2009; 113(41):17768. · 4.80 Impact Factor
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Sheng-Tao Yang,
Xin Wang,
Haifang Wang,
Fushen Lu, Pengju G Luo,
Li Cao,
Mohammed J Meziani,
Jia-Hui Liu,
Yuanfang Liu,
Min Chen,
Yipu Huang,
Ya-Ping Sun
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ABSTRACT: Fluorescent carbon dots (small carbon nanoparticles with the surface passivated by oligomeric PEG molecules) were evaluated for their cytotoxicity and in vivo toxicity and also for their optical imaging performance in reference to that of the commercially supplied CdSe/ZnS quantum dots. The results suggested that the carbon dots were biocompatible, and their performance as fluorescence imaging agents was competitive. The implication to the use of carbon dots for in vitro and in vivo applications is discussed.
The Journal of Physical Chemistry C 09/2009; 113(42):18110-18114. · 4.80 Impact Factor
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ABSTRACT: It was found and recently reported that small carbon nanoparticles can be surface-passivated by organic or biomolecules to become strongly fluorescent. These fluorescent carbon nanoparticles, dubbed "carbon dots", can be successfully used for in vitro cell imaging with both one- and two-photon excitations, as already demonstrated in the literature. Here we report the first study using carbon dots for optical imaging in live mice. The results suggest that the carbon dots remain strongly fluorescent in vivo, which, coupled with their biocompatibility and nontoxic characteristics, might offer great potential for imaging and related biomedical applications.
Journal of the American Chemical Society 09/2009; 131(32):11308-9. · 9.91 Impact Factor
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Advanced Materials 12/2008; 21(2):139 - 152. · 13.88 Impact Factor
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ABSTRACT: There have been rapid advances in the development and applications of semiconductor quantum dots (QDs) represented by CdSe/ZnS. However, a serious limitation of these QDs is the necessary use of toxic heavy metals. It is reported here that small carbon nanoparticles doped with inorganic salts serve as a highly promising new platform for brightly photoluminescent dots. The photoluminescent carbon dots with the carbon core doped with ZnO (C(ZnO)-Dots) or ZnS (C(ZnS)-Dots) in aqueous solutions are competitive to the commercially available CdSe/ZnS QDs in luminescence brightness.
The Journal of Physical Chemistry C 12/2008; 112(47):18295-18298. · 4.80 Impact Factor
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Lingrong Gu, Pengju G Luo,
Haifang Wang,
Mohammed J Meziani,
Yi Lin,
L Monica Veca,
Li Cao,
Fushen Lu,
Xin Wang,
Robert A Quinn,
Wei Wang,
Puyu Zhang,
Sebastian Lacher,
Ya-Ping Sun
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ABSTRACT: Single-walled carbon nanotube (SWNT) is a pseudo-one-dimensional nanostructure capable of carrying/displaying a large number of bioactive molecules and species in aqueous solution. In this work, a series of dendritic beta-D-galactopyranosides and alpha-D-mannopyranosides with a terminal amino group were synthesized and used for the functionalization of SWNTs, which targeted the defect-derived carboxylic acid moieties on the nanotube surface. The higher-order sugar dendrons were more effective in the solubilization of SWNTs, with the corresponding functionalized nanotube samples of improved aqueous solubility characteristics. Through the functionalization, the nanotube apparently serves as a unique scaffold for displaying multiple copies of the sugar molecules in pairs or quartets. Results on the synthesis and characterization of these sugar-functionalized SWNTs and their biological evaluations in binding assays with pathogenic Escherichia coli and with Bacillus subtilis (a nonvirulent simulant for Bacillus anthracis or anthrax) spores are presented and discussed.
Biomacromolecules 10/2008; 9(9):2408-18. · 5.48 Impact Factor
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Advances in applied microbiology 02/2008; 63:145-81. · 5.23 Impact Factor
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Li Cao,
Xin Wang,
Mohammed J Meziani,
Fushen Lu,
Haifang Wang, Pengju G Luo,
Yi Lin,
Barbara A Harruff,
L Monica Veca,
Davoy Murray,
Su-Yuan Xie,
Ya-Ping Sun
Journal of the American Chemical Society 10/2007; 129(37):11318-9. · 9.91 Impact Factor
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ABSTRACT: There has been significant interest in the binding of anthrax spores by molecular species, but with only limited success. Proteins and more recently peptides were used. However, despite the known presence of carbohydrates on the spore surface, carbohydrate-carbohydrate interactions have hardly been explored likely because of the lack of required specific platform for synthetic carbohydrates. We report the successful use of single-walled carbon nanotubes as a truly unique scaffold for displaying multivalent monosaccharide ligands that bind effectively to anthrax spores with divalent cation mediation to cause significant spore aggregation. The work should have far-reaching implications in development of countermeasure technologies.
Journal of the American Chemical Society 11/2006; 128(41):13364-5. · 9.91 Impact Factor
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Ya-Ping Sun,
Bing Zhou,
Yi Lin,
Wei Wang,
K A Shiral Fernando,
Pankaj Pathak,
Mohammed Jaouad Meziani,
Barbara A Harruff,
Xin Wang,
Haifang Wang, Pengju G Luo,
Hua Yang,
Muhammet Erkan Kose,
Bailin Chen,
L Monica Veca,
Su-Yuan Xie
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ABSTRACT: We report that nanoscale carbon particles (carbon dots) upon simple surface passivation are strongly photoluminescent in both solution and the solid state. The luminescence emission of the carbon dots is stable against photobleaching, and there is no blinking effect. These strongly emissive carbon dots may find applications similar to or beyond those of their widely pursued silicon counterparts.
Journal of the American Chemical Society 07/2006; 128(24):7756-7. · 9.91 Impact Factor
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ABSTRACT: Polymeric nanoparticles with surface-tethered mannoses were synthesized for the binding to bacteria bearing mannose-specific adhesins, as reported previously. Presented here are experimental results that quantify the magnitude of cell aggregation mediated by the bioactive nanoparticles. The colony forming unit (CFU) assay suggested a reduction of up to 99%, consistent with the fluorescence microscopy images showing large bacterial cell clumps of hundreds to thousands of bacteria. The specificity of the bacterial-binding and potential applications of the bioactive nanoparticles as antibacterial agents are discussed.
Journal of Biomedical Nanotechnology 08/2005; 1(3):291-296. · 4.22 Impact Factor
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ABSTRACT: Polymeric nanoparticles covalently functionalized with derivatized D-mannose molecules were synthesized and characterized. These nanoparticles have an average size of approximately 160 nm in diameter, thus bearing a large number of surface-tethered mannose moieties for multivalent interactions with adhesins on bacterial cells. Specifically, the mannosylated nanoparticles bind strongly with Escherichia coli, allowing the convenient visualization of adhesion interactions under a conventional electron microscope. Since a single nanoparticle is capable of binding more than one cell, the adhesion interactions result in significant nanoparticle-mediated cell agglutination according to electron microscopy imaging. Potential applications of the mannosylated nanoparticles in the inhibition of enteropathogenic infections are discussed.
Journal of Nanoscience and Nanotechnology 03/2005; 5(2):319-22. · 1.56 Impact Factor
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Liangwei Qu,
Lingrong Gu,
Huaping Li,
Shelby Taylor,
Tara Elkin, Pengju G. Luo,
Tzuen-Rong J. Tzeng,
Xiuping Jiang,
Robert A. Latour,
Fred Stutzenberger,
Alicia Williams,
Ya-Ping Sun
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ABSTRACT: Polymeric nanoparticles of a polystyrene core and polyethylene glycol corona were prepared via dispersion copolymerization of styrene with a specifically synthesized macromonomer. The particle surface tethers were terminated covalently with derivatized galactose moieties. These galactosylated polymeric nanoparticles were characterized by using dynamic light scattering, electron microscopy, NMR, and other techniques. Bioactivities of the nanoparticles were evaluated and demonstrated by their significant adhesion interactions with several Escherichia coli strains.
Journal of Biomedical Nanotechnology 02/2005; 1(1):61-67. · 4.22 Impact Factor
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ABSTRACT: Consumption of berries has become popular among health-conscious consumers due to the high levels of valuable antioxidants, such as anthocyanins, and phenolic compounds in berries. Four Rabbiteye blueberry cultivars (i.e., Powderblue, Climax, Tifblue, and Woodward) grown organically and conventionally were compared regarding their chemical profiles and antioxidant capacity in terms of total phenolic content (TPC), total anthocyanin content (TAC) and ORAC activity. Regardless of the high TPC, TAC and ORAC in both organically and conventionally grown blueberries, not all the organic berries showed significantly higher TPC, TAC and ORAC than the conventional berries. The chemical profiles (i.e., the free phenolic compounds and anthocyanins) were determined with aid of HPLC-MS, by which 13 individual anthocyanins and seven free phenolics were identified. This study demonstrated the subtle differences of bioactive phytochemicals between the organically and conventionally grown berries.
Food Chemistry. 125(1):201-208.
