To ensure that the reproducibly observed cell death is caused by hypericin-induced PDT and is not solely a result of photodamage caused by the laser irradiation, control measurements of glioma cells that were not incubated with hypericin were performed at laser powers larger than the ones used for hypericin PDT induction of 7-9 µW/µm 2 at 𝜆 exc = 405 nm. These control experiments of cells without hypericin incubation are displayed and discussed in section 5 of the SI. In summary, without the presence of the PDT sensitizer hypericin, we observed no significant cell damage after irradiating the single glioma cells in a comparable manner.