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Mun D.-H.,Korea Institute of Science and Technology | Lee H.J.,Korea Institute of Science and Technology | Lee H.J.,BioNano Health Guard Research Center | Bae S.,Korea Institute of Science and Technology | And 4 more authors.
Physical Chemistry Chemical Physics | Year: 2015

Highly reactive radicals or chemicals are generated on the surfaces of oxide semiconductors via reactions between photo-induced charges and ambient gas molecules. These radicals or chemicals have been utilized in heterogeneous photosynthesis and photocatalysis. In this study, we demonstrated that the photocatalytic reactions on the surface of ZnO promoted the oxidation and decomposition of graphene. Raman spectra were used to analyze the evolution of the G and 2D peaks. The oxidation of graphene on a ZnO substrate by UV radiation was faster than that in the absence of ZnO. During oxidation, the resistivity and the transmittance of graphene also increased. The XPS results showed that functional groups related to the oxidation of graphene were formed during the photocatalytic reactions. This simple and clean approach will be also effective for selective surface modification by enhancing the surface chemical reactions that pattern graphene via oxidation. © the Owner Societies 2015.

Kim S.-J.,Korea Research Institute of Bioscience and Biotechnology | Chung B.H.,Korea Research Institute of Bioscience and Biotechnology | Chung B.H.,BioNano Health Guard Research Center
Carbohydrate Polymers | Year: 2016

Levan coated cerium oxide nanoparticles (LCNPs) with the enhanced antioxidant activity were successfully synthesized and characterized. Levan and their derivatives are attractive for biomedical applications attributable to their antioxidant, anti-inflammation and anti-tumor properties. LCNPs were synthesized using the one-pot and green synthesis system with levan. For production of nanoparticles, levan plays a role as a stabilizing and reducing agent. Fourier transform infrared spectroscopy (FT-IR) analysis showed that LCNPs successfully synthesized. The morphology and size of nanoparticles were confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). LCNPs have good water solubility and stability. The conjugation of levan with cerium oxide nanoparticles improved antioxidant activity. Moreover the level of ROS was reduced after treatment of LCNPs to H2O2 stimulated NIH3T3 cells. These results demonstrate that the LCNPs are useful for applying of treatment of ROS induced diseases. © 2016 Elsevier Ltd. All rights reserved.

Kim S.-J.,Korea Research Institute of Bioscience and Biotechnology | Bae P.K.,BioNano Health Guard Research Center | Chung B.H.,Korea Research Institute of Bioscience and Biotechnology | Chung B.H.,BioNano Health Guard Research Center | Chung B.H.,Korean University of Science and Technology
Chemical Communications | Year: 2014

We report on the targeted imaging of breast cancer using self-assembled levan nanoparticles. Indocyanine green (ICG) was encapsulated in levan nanoparticles via self-assembly. Levan-ICG nanoparticles were found to be successfully accumulated in breast cancer via specific interaction between fructose moieties in levan and overexpressed glucose transporter 5 in breast cancer cells. This journal is © The Royal Society of Chemistry.

Jeong J.,Korea Research Institute of Bioscience and Biotechnology | Jeong J.,Korea University | Jeong J.,BioNano Health Guard Research Center | Cho H.-J.,Korea Research Institute of Bioscience and Biotechnology | And 9 more authors.
Carbon | Year: 2015

The toxicity of nano-graphene oxide (NGO) on development and angiogenesis was evaluated using zebrafish embryos as in vivo model system. Microinjection of NGO resulted in gross morphological defects in a dose-dependent manner partly due to the induction of apoptosis, whereas coating NGO derivatives with polyethylene glycol (PEG), a biocompatible polymer significantly attenuated its toxicity. NGO also caused abnormal branching and mispatterning of developing trunk blood vessels monitored by endothelial cell-specific fluorescent transgenic zebrafish, presumably via Vascular Endothelial Growth Factor and Notch pathways, key signaling pathways for normal angiogenic process. Interestingly, Alexa568 conjugated, PEG-coated NGO (NGO-A568) still caused angiogenic defects to the similar degree as NGO did, suggesting differential toxic effects of nanomaterials on different developmental processes. Confocal microscopy imaging of NGO- and NGO-A568-injected embryos visualized its live distribution throughout the body including the cranial vasculature. The broader utilization of embryonic zebrafish combined with in vivo, real-time, high-resolution imaging is warranted for assessing the properties of nanomaterials. © 2015 Elsevier Ltd. All rights reserved.

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