Photoluminescent nanographitic/nitrogen-doped graphitic hollow shells as a potential candidate for biological applications

Ji Eun Park, Ekaterina D. Grayfer, Yeongri Jung, Kyung Kim, Kang Kyun Wang, Yong Rok Kim, Duhee Yoon, Hyeonsik Cheong, Hae Eun Chung, Soo Jin Choi, Jin Ho Choy, Sung Jin Kim

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11 Scopus citations


Water-dispersible graphitic hollow spheres were synthesized using a soft chemical route under hydrothermal conditions by glucose carbonization using a magnetite/silica-encapsulated core-shell sphere as a template. Carbonization on the templates happens as the magnetite core is partially or completely eliminated depending on the reaction conditions. Therefore, nano-sized graphitic hollow spheres or magnetite-core-encapsulated graphitic shells could be obtained. Also nitrogen-doped graphitic spheres were synthesized by a hydrothermal reaction. The graphitic and nitrogen-doped graphitic spheres show wavelength dependent photoluminescence in 300-600 nm range. The photoluminescence seems to depend on the fraction of the sp2 domains and N-doping, therefore, tunable PL emission can be achieved by controlling the nature of sp2 sites. In addition the cellular uptake of the graphitic hollow spheres was evaluated in human HeLa cells, demonstrating its main localization in the cytoplasm. A blue fluorescence signal was the most intensively observed in the cellular uptake process, although some green and red fluorescence was also observed. Since the cores of Fe3O4 could be completely or partly eliminated in a controllable way, it can be used as a magnetic resonance imaging agent. In addition, their easily modifiable hydrophilic surfaces for multi-functionality and hydrophobic voids covered by oxidized graphite make them promising candidates for applications in cellular photo-imaging and targeted drug delivery.

Original languageEnglish
Pages (from-to)1229-1234
Number of pages6
JournalJournal of Materials Chemistry B
Issue number9
StatePublished - 7 Mar 2013


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