– PKH67 is a fluorescent cell-binding dye with green fluorescence, capable of staining cell membranes, with excitation/emission (Ex/Em) at 490/502 nm. It is often used in combination with the non-specific red fluorescent dye PKH26 (Ex/Em=551/567 nm) to label cells, detect cell proliferation in vitro, and trace cells both in vitro and in vivo [1] [2].