Detection of photosensitized singlet oxygen luminescence in systems of biomedical importance: steady-state and time-resolved measurements based on application of S-1 photomultiplier tubes

A series of supersensitive apparatuses constructed in the laboratory of this author for the steady-state, time-resolved and combined time-resolved-spectral measurements of infrared luminescence of singlet molecular oxygen has been described. All apparatuses were based on the use of cooled S-1 photomultipliers. Steady-state measurements were carried out using mechanical phosphoroscopes or the mode of a conventional fluorimeter. Time-resolved measurements were performed using pulsed lasers and averaging photon counting electronics based on the use of multichannel analyzers. This technique allowed pioneering measurements of photosensitized singlet oxygen luminescence in organic and aqueous media and systematic investigation of generation and quenching of singlet oxygen by numerous biologically important compounds. The data suggest that the development of the PMT-based technique for detection of singlet oxygen luminescence is highly promising for various biomedical applications and might be useful for imaging photodynamically active sites of living tissues.