Synthesis and advanced characterization of stable Ag2S quantum dots for in vivo imaging

The goal of the project was to produce Ag2S nanocrystals (i.e. quantum dots, QDs) with tunable photoluminescence emission in the NIR-I and NIR-II range and no toxicity, to be used as bioimaging probes. We developed two aqueous synthesis methods using GSH as a sulfur source and capping agent, both yielding biocompatible, mostly non-toxic QDs. In the microwave-assisted (MW) approach, the PL emission could span the range 900-1300 nm, and be tuned by modulating reaction parameters as the precursor ratio and reaction time.[1] In addition to standard characterization methods, we used X-ray Absorption Spectroscopy (XAS) to unveil the mechanism of growth of the QDs, and their transformation in hepatic cells.[2] The non-toxic, NIR-emitting Ag2S QDs that are stable in cells hold great promise for in vivo imaging.