Cadmium-free quantum dots as time-gated bioimaging probes in highly-autofluorescent human breast cancer cells.

We report cadmium-free, biocompatible (Zn)CuInS2 quantum dots with long fluorescence lifetimes as superior bioimaging probes using time-gated detection to suppress cell autofluorescence and improve the signal : background ratio by an order of magnitude. These results will be important for developing non-toxic fluorescence imaging probes for ultrasensitive biomedical diagnostics.