By punching tiny holes in the protective membranes of cells, researchers lead by Mark Prausnitz, Georgia Institute of Technology, USA, have demonstrated a new technique for getting therapeutic small molecules, proteins and DNA directly into living cells.

The technique involves introducing the therapeutic agents and nanoparticles of carbon black into the fluid surrounding the, irradiating the fluid with near-infrared light from a femotosecond laser at a rate of 90 million pulses per second. The absorbed light heats the nanoparticles, turning the surrounding fluid to steam which forms bubbles of H₂ and CO.

When the bubbles collapse, they create shock waves that punch holes in the membranes of nearby cells. The openings allow therapeutic agents from the surrounding fluid to enter the cells. The holes quickly close so the cell can survive.

• Delivery of molecules into cells using carbon nanoparticles activated by femtosecond laser pulses
  P. Chakravarty, W. Qian, M. A. El-Sayed, M. R. Prausnitz
  Nat. Nanotechnol. 2010, 5.
  DOI: 10.1038/nnano.2010.126