These experiments demonstrate that the uptake efficiency depends on the generation of the dendron (higher generation leads to improved uptake) and the periphery modification of the dendron (amine is better than guanidine at this specific timepoint in the experimental setup). Importantly, all tested compounds were found to be stable in the zebrafish extracts over a period of 48 hours (Figure ). Of note, 21 and 22 showed different behavior in uptake into living HeLa cells (see above,