For imaging a custom-built setup was used. A 561 nm laser for NIR fluorescence excitation (Cobolt Jive TM ) was coupled into an Olympus IX73 microscope equipped with a 100× (UPlanSApo 100×/1.35 Sil, Olympus) oil immersion objective. NIR and brightfield could simultaneously be imaged. For NIR imaging a Xenics Cheetah TE1 InGaAs camera was used. A dichroic mirror (VIS/NIR, HC BS R785 lambda/5 PV, F38-785, AHF) and a 900 nm long-pass filter (FELH0900, Thorlabs) were installed in the beam path between objective and cameras. NIR images where acquired with 60 mW excitation laser power at 1 fps (0.9 s exposure time). Cells were seeded into 96 glass-bottom well plates (P96-0-N, Cellvis) which were placed on the microscope. Temperature was kept constant at 37 °C by placing an incubation chamber (Tokai Hit STXG-DMIWX) on top of the well plate on the microscope.