Glucose-functionalized near-infrared Ag2Se quantum dots with renal excretion ability for long-term in vivo tumor imaging

Non-toxic and long-term fluorescent probes for tumor imaging are in urgent need for non-invasively obtaining information about tumor genesis and metastasis in vivo. Here, we present a biocompatible near-infrared fluorescent probe for in vivo long-term imaging of tumor by modifying glucose (Glc), which experiences high uptake in cancer cells, on the surface of near-infrared Ag2Se quantum dots (NIR Ag2Se QDs). The fluorescence of glucose-functionalized Ag2Se QDs (Glc-Ag2Se QDs) from the targeted tumor can be observed in vivo for at least 7 days. In addition, this probe could be excreted through kidneys and the renal excretion ability is favorable for in vivo imaging applications. Moreover, Glc-Ag2Se QDs could be used for tumor targeted imaging of not only human breast cancer cells (MCF-7), but also SW1990 pancreatic cancer cells since glucose is highly taken up in almost all kinds of tumors. Glc-Ag2Se QDs could be a promising general tool for in vivo long-term observation of tumor evolution.