Preparation and bioapplication of high-quality, water-soluble, biocompatible, and near-infrared-emitting CdSeTe alloyed quantum dots

A facile method is developed for the preparation of high-quality, water- soluble, and near-infrared (NIR)-emitting CdSeTe alloyed quantum dots (AQdots) with L-cysteine as the capping agent. By changing the size and the composition of AQdots the photoluminescent quantum yield (QY) can reach as high as 53% and the emission color can be tuned between visible and NIR regions (580-814 nm). Furthermore, the prepared NIR-emitting AQdots have been successfully applied for HL-60 cell imaging and glucose and cholesterol assay, which demonstrates the great potential of the AQdots for biological applications.