Mechanochemical Synthesis of Sulfur Quantum Dots for Cellular Imaging

A mechanochemical synthesis of luminescent sulfur quantum dots (Sdots) is demonstrated for the first time to reduce the synthesis reaction time. Structural characterization using X-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectroscopy confirmed the formation of Sdots. The present method produced Sdots through a short-chain polymerization of sulfur and features an excitation-dependent photoluminescence with a quantum yield of 4.8%, high photostability, excellent hydrophilicity, and low toxicity. Further, Sdots were seen to cause a low toxicity in both normal and cancer cells, which makes this a promising candidate for bioimaging and biolabeling.