Near-infrared broadly emissive AgInSe2/ZnS quantum dots for biomedical optical imaging

Highly luminescent AgInSe2/ZnS core/shell quantum dots (AISe/ZnS QDs) have been synthesized via a facile low-temperature solution chemistry route. The as-prepared core/shell QDs have a narrow size distribution, and exhibit composition-tunable photoluminescence (PL) emission in the near-infrared (NIR) range from 700 to 820 nm with a maximum PL quantum yield (QY) of 40%. By using the poly(acrylic acid)-octylamine (PAA-based) amphiphilic polymer, these oil-soluble AISe/ZnS core/shell QDs could be effectively solubilized in water, while retaining their initial morphology, crystal structure and PL properties. Importantly, the results from animal and cell experiments confirm that these highly luminescent, broadly emissive AISe/ZnS QDs are new promising fluorescent probes for biomedical optical imaging (namely, in vivo animal and in vitro cell imaging), as an alternative for Cd-, Hg- and Pb-based QDs and organic dyes.