Green synthesis of multi-color emissive carbon dots from Manilkara zapota fruits for bioimaging of bacterial and fungal cells

J Photochem Photobiol B. 2019 Feb:191:150-155. doi: 10.1016/j.jphotobiol.2018.12.023. Epub 2019 Jan 4.

Abstract

Natural resources have widely been used as precursors for the preparation of ultra-small carbon dots (C-dots) due to ease of availability, low cost and C-dots with high quantum yields (QYs). Herein, water dispersible multi-color emissive C-dots were obtained from Manilkara zapota fruits. The emission of C-dots was well tuned by sulphuric acid and phosphoric acids, which results to generate blue-, green- and yellow- C-dots. The fabricated C-dots exhibit blue, green and yellow color emissions when irradiated them under UV light at 365 nm. The emission/excitation peaks of blue-, green-, and yellow- C-dots were observed at 443, 515 and 563 nm when excited at 350, 420 and 440 nm, respectively. The QYs of blue-, green-, and yellow- C-dots are 5.7, 7.9 and 5.2%. The average sizes of blue- green- and yellow- C-dots are 1.9 ± 0.3, 2.9 ± 0.7and 4.5 ± 1.25 nm, respectively. Because of ultra-small size and biocompatibility, three C-dots act as promising bioimaging agents for imaging of cells (E. coli, Aspergillus aculeatus and Fomitopsis sp). The cytotoxicity on HeLa cells indicates that three C-dots have non-toxic nature, which confirms their biocompatibility. The ultra-small C-dots were effectively distributed in the cytoplasm of the cells, ensuring the potential applications in cell imaging and biomedical studies.

Keywords: Bioimaging; Fluorescent C-dots; Manilkara zapota fruits; Multi-color emission.

MeSH terms

  • Bacteria / cytology
  • Carbon
  • Color
  • Fungi / cytology
  • Green Chemistry Technology*
  • HeLa Cells
  • Humans
  • Manilkara / chemistry*
  • Optical Imaging / methods*
  • Quantum Dots / chemistry*
  • Ultraviolet Rays

Substances

  • Carbon