Fig. 3

Cell internalization of functionalized NDs in a fibroblast cell line. a Merged image of fibroblast cells with Alexa 488 labeled tubulin excited with 488 nm laser illumination (green) and fNDs excited with 532 nm illumination (red). In both cases, the emission was recorded using an avalanche photon detector (APD). b Fluorescence spectrum of nanodiamonds showing the characteristic zero phonon lines at 637 and 575 nm. c Fluorescence spectrum of Alexa 488