S,N-Co-doped carbon nanoparticles with high quantum yield for metal ion detection, IMP logic gates and bioimaging applications

In this paper, we reported a facile approach for the preparation of sulfur and nitrogen co-doped carbon nanoparticles (S,N-CNPs) with strong blue luminescence, which exhibited multiple applications including metal ion detection, logic gate fabrication and bioimaging. S,N-CNPs were synthesized by one-step hydrothermal treatment of formamidine sulfinic acid (FAS) and ethylene glycol. The as-synthesized S,N-CNPs possess a high quantum yield (Φ = 69.04%) and display excellent photostability and storage stability. By modulating the pH environment, S,N-CNPs were successfully applied as fluorescent probes for the detection of three kinds of heavy metal ions (Hg2+, Ag+ and Ni2+). The fabricated fluorescence sensors display ultrahigh sensitivity and a wider signal response range. More importantly, ethylenediamine (or ammonium thioglycolate and glycine) could efficiently release Hg2+ (or Ag+ and Ni2+) from the S,N-CNP surface, leading to the recovery of the fluorescence. According to this phenomenon, interesting implication (IMP) logic gates were constructed. In addition, the S,N-CNPs exhibited low toxicity, good biocompatibility and easy cellular uptake behavior. Consequently, the obtained S,N-CNPs will have potential applications in multiple fields of environmental monitoring, logic gate operation, and cell bioimaging.