Duke University physicists have developed a way to produce sharp fluid jets with enough precision that they can inject material into a single, living cell. The technique promises a way to deliver drugs to cells one at a time, which is likely to be very valuable for research involving stem cells and other cellular-level studies. The research appears in the current issue of the APS journal Physical Review Letters. The physicists produced the jets by focusing lasers into a fluid surrounding a target cell. The lasers heated molecules（分子，微粒） of a blue dye（燃料） dissolved in the fluid, which in turn created tiny bubbles to rapidly grow and collapse. When these sorts of bubbles are produced individually, they create shock waves that spread throughout the liquid. But producing two adjacent（邻近的，毗邻的） bubbles in rapid succession results in small, powerful jets capable of poking（刺） tiny holes, measuring only 0.2 millionths of a meter across, in cell membranes（细胞膜，薄膜） .

The researchers confirmed that the jets allowed the introduction of fluids into the cell by checking for signs of the blue dye inside the pierced cells. The dye is toxic, and it killed the pierced cells, but the holes the jets produced were small enough that it's likely that the jets will offer a way to inject live cells with nontoxic（无毒的） substances without significantly damaging them.

Claus-Deiter Ohl of Nanyang Technological University in Singapore provides further information about the fluid jets and related research in a Viewpoint article in the current edition of APS Physics (physics.aps.org).