Publications by authors named "Jin Gwan Seo"

2 Publications

  • Page 1 of 1

Biological Potential of Polyethylene Glycol (PEG)-Functionalized Graphene Quantum Dots in In Vitro Neural Stem/Progenitor Cells.

Nanomaterials (Basel) 2021 May 29;11(6). Epub 2021 May 29.

Institute of Tissue Regeneration Engineering (ITREN), Dankook University, 119 Dandae-ro, Cheonan 31116, Korea.

Stem cell therapy is one of the novel and prospective fields. The ability of stem cells to differentiate into different lineages makes them attractive candidates for several therapies. It is essential to understand the cell fate, distribution, and function of transplanted cells in the local microenvironment before their applications. Therefore, it is necessary to develop an accurate and reliable labeling method of stem cells for imaging techniques to track their translocation after transplantation. The graphitic quantum dots (GQDs) are selected among various stem cell labeling and tracking strategies which have high photoluminescence ability, photostability, relatively low cytotoxicity, tunable surface functional groups, and delivering capacity. Since GQDs interact easily with the cell and interfere with cell behavior through surface functional groups, an appropriate surface modification needs to be considered to get close to the ideal labeling nanoprobes. In this study, polyethylene glycol (PEG) is used to improve biocompatibility while simultaneously maintaining the photoluminescent potentials of GQDs. The biochemically inert PEG successfully covered the surface of GQDs. The PEG-GQDs composites show adequate bioimaging capabilities when internalized into neural stem/progenitor cells (NSPCs). Furthermore, the bio-inertness of the PEG-GQDs is confirmed. Herein, we introduce the PEG-GQDs as a valuable tool for stem cell labeling and tracking for biomedical therapies in the field of neural regeneration.
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May 2021

Versatile and Tunable Electrical Properties of Doped Nonoxidized Graphene Using Alkali Metal Chlorides.

ACS Appl Mater Interfaces 2019 Nov 5;11(45):42520-42527. Epub 2019 Nov 5.

Division of Advanced Materials Engineering , Kongju National University , Cheonan , Chungnam 32588 , Republic of Korea.

With the rapid development of wearable and flexible electronics, graphene has been intensively studied for the transparent, hole transport electrode layer (HTL) of field-effect transistors, light-emitting diodes, and organic photovoltaic (OPV) cells. To modulate the sheet resistance and the work function of graphene as a HTL, the surface doping is versatile while retaining high transparency. In this work, we used a chemical doping method to control the charge carrier density, band gap, and work function of graphene with minimizing the damage of the carbon network, for which metal chlorides (NaCl, KCl, and AuCl) were used as chemical dopants. The high-quality graphene flakes were synthesized with large lateral sizes of more than 5 μm using ternary graphite intercalation compounds. Interestingly, the AuCl-doped graphene flake film with a film thickness of about 20 nm showed the lowest reported sheet resistance of ∼249 Ω/sq with ∼75% transmittance. Furthermore, it could control the work function from 4.32 to 5.1 eV. The interfacial dipole complexes of metal cations with a low work function and the reactive radicals such as -OH were discussed to explain this result. For the practical application, an OPV device using the AuCl-doped graphene flake film as the HTL was fabricated and it demonstrated enhanced power conversion efficiency while maintaining high optical transparency in visible light.
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November 2019