Unveiling the interaction between PDT active squaraines with ctDNA: A spectroscopic study

• Interaction between Br- and I-C4 squaraines with ctDNA was investigated. Br-C4 binds on the minor groove. Squaraines display great affinity toward DNA K A values order of 10 5 M −1 . could be employed as potential probes for ctDNA. Squaraine dyes are photosensitizers in photodynamic therapy (PDT) due to their ability release reactive oxygen species (ROS) cause damage. For this reason, evaluation determination type interaction is utmost importance. In study different spectroscopic techniques such UV–Vis fluorescence spectroscopies were used investigate that occurs two (halogenated squaraines, i.e. I-C4) calf thymus (ctDNA). found bind externally following a groove binding they able replace Hoechst (a classic binder) from DNA. This mode further supported by iodide quenching studies, ionic strength assay Florescence Resonance Energy Transfer. Moreover, association (K ) dissociation D constants obtained compared well-known binders.