Figure 3.

Methods for measuring phototoxicity. (a) ‘Destructive read-outs’ are techniques prohibiting further imaging of the sample. These include blotting for phosphorylated forms of proteins present in damage-activated pathways [51] and flow cytometry for determining the population of cells expressing, for example, apoptotic markers such as annexin V. (b) ‘Fluorescent reporters’ are additional indicators added to the sample during imaging whose fluorescence signal changes in response to e.g. intracellular Ca²⁺ concentration (top) or mitochondrial membrane potential (bottom). ‘Label-free methods’ of quantifying phototoxicity involve: (c) short-term observation of cell division and morphology and (d) proliferation of cells in culture following imaging. Reproduced from [51]. CC BY 4.0.