Cannabis sativa-derived carbon dots co-doped with N-S: Highly efficient nanosensors for temperature and vitamin B12

Abstract

With the enhancement in biomimetic and bioinspired synthesis approaches, plant-derived nanostructures provide the most suitable synthesis alternatives in terms of being non-toxic, economical and eco-friendly. The present work focused on Cannabis sativa-derived carbon dots co-doped with nitrogen and sulphur (N-S@CsCD) as a nanosensor. N-S@CsCD exhibited size distribution in the range of 4-6 nm and showed an excitation-independent emission behaviour with an emission wavelength around 414 nm. The XPS spectra confirmed the presence of heteroatom doping by nitrogen and sulphur with the concentrations of 10.71% and 1.94%, respectively. N-S@CsCD showed excellent stability to pH, time and salt concentration. Interestingly, N-S@CsCD exhibited a reversible temperature-responsive fluorescence "turn-off" behaviour. Furthermore, N-S@CsCD showed a selective fluorescence "turn-off" behaviour in the presence of vitamin B12 (VB12), with a limit of detection of 7.87 μg mL-1. The fluorescence lifetimes of N-S@CsCD with and without VB12 were similar, which implied that the sensing behaviour was purely static in nature. Moreover, N-S@CsCD showed biocompatible and non-toxic behaviours with very high cell viability. The fluorescence nature of N-S@CsCD was further evaluated for intracellular imaging. © 2019 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.