A streptavidin paramagnetic-particle based competition assay for the evaluation of the optical selectivity of quadruplex nucleic acid fluorescent probes

► We describe a method to determine the optical selectivity of G4-nucleic acid probes. ► Five fluorescent probes have been examined. ► Any DNA or RNA intramolecular G4 target can be used. ► Any type of competitor can be used: total DNA and RNA, proteins, other G4, etc. ► The assay is fast and easy to implement.