Method, device and computer program for localizing and/or imaging light-emitting molecules in a sample

A method for localizing and/or imaging light-emitting molecules in a sample contained in a sample reservoir comprising:

• illuminating the sample by a light source comprised in or connected to a microscope,
• detecting light emitted by the light-emitting molecules in the sample by a detector comprised in or connected to the microscope, wherein the light-emitting molecules comprise a bright state, in which the light-emitting molecules emit light in response to being illuminated and a dark state, in which the light-emitting molecules do not emit light in response to being illuminated or in which the light-emitting molecules emit less light in response to being illuminated than in the bright state,
• determining, based on the detected light, a current value of one or more parameters, wherein at least one of the parameters co-depends on photo-physical or photo-chemical properties of the light-emitting molecules other than their average photon emission rate, and
• automatically adjusting a composition of a fluid in the sample reservoir to optimize the one or more parameters during the localization or imaging of the light-emitting molecules.