Carbon dots derived from an aminonaphthalene sulfonic acid as sensitive activated fluorescent probes for chemosensing and imaging applications

Abstract

The presence of toxic residues in water and food is a constant concern that requires the development of fast and low-cost analytical methods for controlling and monitoring environmental conditions and physicochemical processes. In this context, the current study examines the physical and chemical properties of carbon dots (CD-ANS) produced through hydrothermal synthesis using 5-amino-2-naphthalenesulfonic acid (ANS) as a precursor. Different experimental techniques are used to characterize CD-ANS’s shape and photoluminescent properties. Our results show that such carbon dots are co-doped with nitrogen and sulfur, displaying a broad emission spectrum sensitive to small environmental changes. In particular, CD-ANS exhibits an activated fluorescence in the presence of certain organic pollutants, thus being suitable for various chemosensing applications, including ratiometric sensing of pH, methanol, and a carbamate pesticide (methomyl). Thermal effects on the nanoparticle’s photoluminescence are also analyzed, where the occurrence of a thermally-activated mechanism is identified. The possibility of using CD-ANS in staining yeast cells has also been investigated. These findings suggest that the carbon dots derived from ANS can be a versatile fluorescent platform for various physical, chemical, and biological applications.