Proton implantation into living cells under nonvacuum atmosphere

We report direct proton implantation into living cells by using a palm-sized ion emission gun under a nonvacuum atmosphere at room temperature (25 °C). An injection needle was coated with Nafion® to prepare the proton emission gun, and a polyaniline membrane was used as the target for the proton emission test. After the test, the polyaniline showed structural changes associated with protonation, suggesting successful proton emission from the gun. The device was then used to perform proton implantation into fibroblast-like cells. The viability and metabolic activity of the cells implanted with protons decreased with increasing proton dose within the picomole range. These are the first reported results to show that proton implantation can be effective in supplying direct, localized stimuli to living cells.