PALM/TIRF

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This microscope was custom-built by the Kapanidis lab in Physics. It can be used for PALM and dSTORM experiments under TIRF or near-TIRF conditions up to 1 µm into the cell. Both methods are used to localise single molecules beyond the diffraction limit. TIRF and near-TIRF localisation is limited to 2D with no z-information. Localisation accuracy depends on a high number of detected photons and on only a fraction of molecules being in a fluorescent state at any one time. The latter is achieved in PALM by the activation of only a few fluorophores at the same time, which then bleach irreversibly, and in dSTORM by reversible switching between a fluorescent on-state and a dark off-state. PALM uses photoactivatable fluorescent proteins and dSTORM images fluorescent organic dyes. Cells need to be in an aqueous medium and for dSTORM need to be imaged in switching buffer.

For more information please contact micron@bioch.ox.ac.uk.