Chemosensors (Jul 2021)

An Active Surface Preservation Strategy for the Rational Development of Carbon Dots as pH-Responsive Fluorescent Nanosensors

  • Ana Carolina P. Afonso,
  • Ana Salomé Correia,
  • Diana Duarte,
  • Ana T. S. C. Brandão,
  • Maria del Valle Martínez de Yuso,
  • José Jiménez-Jiménez,
  • Nuno Vale,
  • Carlos M. Pereira,
  • Manuel Algarra,
  • Luís Pinto da Silva

DOI
https://doi.org/10.3390/chemosensors9080191
Journal volume & issue
Vol. 9, no. 8
p. 191

Abstract

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Here we report the rational development of a carbon dot (CDs)-based fluorescent pH nanosensor by employing an active surface preservation strategy. More specifically, citric acid, urea and fluorescein were subjected to a one-pot hydrothermal treatment, which preserved fluorescein-like structures on the surface of the CDs. The obtained CDs showed pH-sensitive green emission, which can be used to determine pH variations from 3.7 to 12.1 by fluorescence enhancement. Moreover, the obtained nanoparticles showed excellent selectivity toward pH, fluorescence reversibility in different pH values, photostability, while being compatible with human cell lines (even at high concentrations). Furthermore, their performance as pH sensors was comparable with reference pH determination procedures. Thus, an active surface preservation strategy was successfully employed to develop fluorescence pH nanosensors in a rational manner and without post-synthesis functionalization strategies, which show potential for future use in pH determination.

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