Nanomaterials (Nanomaterials)

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Preparation and Characterization of Photoluminescent Graphene Quantum Dots from Watermelon Rind Waste for the Detection of Ferric Ions and Cellular Bio-Imaging Applications

  • Chatchai Rodwihok (Civil and Environmental Engineering, Konkuk University) ;
  • Tran Van Tam (School of Chemical Engineering, University of Ulsan) ;
  • Won Mook Choi (School of Chemical Engineering, University of Ulsan) ;
  • Mayulee Suwannakaew (Civil and Environmental Engineering, Konkuk University) ;
  • Sang Woon Woo (Civil and Environmental Engineering, Konkuk University) ;
  • Duangmanee Wongratanaphisan (Department of Physics and Materials Science, Faculty of Science, Chiang Mai University) ;
  • Han S. Kim (Civil and Environmental Engineering, Konkuk University)
  • Received : 2022.02.01
  • Accepted : 2022.02.17
  • Published : 2022.02.20
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Abstract

Graphene quantum dots (GQDs) were synthesized using watermelon rind waste as a photoluminescent (PL) agent for ferric ion (Fe3+) detection and in vitro cellular bio-imaging. A green and simple one-pot hydrothermal technique was employed to prepare the GQDs. Their crystalline structures corresponded to the lattice fringe of graphene, possessing amide, hydroxyl, and carboxyl functional groups. The GQDs exhibited a relatively high quantum yield of approximately 37%. Prominent blue emission under UV excitation and highly selective PL quenching for Fe3+ were observed. Furthermore, Fe3+ could be detected at concentrations as low as 0.28 µM (limit of detection), allowing for high sensitivity toward Fe3+ detection in tap and drinking water samples. In the bio-imaging experiment, the GQDs exhibited a low cytotoxicity for the HeLa cells, and they were clearly illuminated at an excitation wavelength of 405 nm. These results can serve as the basis for developing an environment-friendly, simple, and cost-effective approach of using food waste by converting them into photoluminescent nanomaterials for the detection of metal ions in field water samples and biological cellular studies.

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Acknowledgement

This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP), the Ministry of Trade, Industry and Energy (MOTIE, 20194010201900), the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST, 2019R1A2C1008706), and the Konkuk University Researcher Fund in 2020.