Berkeley scientists have succeeded in injecting a protein-coated quantum dot into a living human cell using a nanotube-tipped atomic force microscope. This is a unique milestone because it represents the first time that researchers have been able to mechanically penetrate a cell wall without damaging it, something a micropipette cannot do. In the near term, this technique will be useful for studying cell biology by injecting almost arbitrary molecules into the intracellular milieu. In the longer term, it could be used for nanomedicine.