From One-Photon to Two-Photon Probes: "Caged" Compounds, Actuators, and Photoswitches

Molecular systems that can be remotely controlled by light are gaining increasing importance in cell biology, physiology, and neurosciences because of the spatial and temporal precision that is achievable with laser microscopy. Two‐photon excitation has significant advantages deep in biological tissues, but raises problems in the design of “smart” probes compatible with cell physiology. This Review discusses the chemical challenges in generating suitable two‐photon probes. A leading light: Molecular systems that can be remotely controlled by light are gaining increasing importance in cell biology and neurosciences because of the spatial and temporal precision that is achievable with laser microscopy. Two‐photon excitation has significant advantages over one‐photon approaches deep in biological tissues, but the design of “smart” probes compatible with cell physiology is challenging.