Dibenzopyridoimidazocinnolinium cations: a new family of light-up fluorescent DNA probes

Abstract

Steady-state and time-resolved fluorescence, circular dichroism and molecular modelling techniques have been applied to a new family of weakly fluorescent dibenzopyridoimidazocinnolinium derivatives whose fluorescence intensity increases significantly (larger than × 3.5) upon DNA addition. The synthesis of these azonia cations, which bind to DNA by intercalation, was carried out using a Westphal condensation and a Suzuki cross coupling reaction as key steps. A live-cell staining analysis by confocal microscopy imaging was also performed and showed the capacity of these new compounds for active uptake and accumulation by living cells, with complex patterns of intracellular distribution observed.