Squaraine dyes are potential photosensitizers in photodynamic therapy (PDT) due to their ability to release reactive oxygen species (ROS) and cause DNA damage. For this reason, the evaluation and determination of the type of interaction between squaraines and DNA is of the utmost importance.

In this study different spectroscopic techniques such as UV-Vis and fluorescence spectroscopies were used to investigate the type of interaction that occurs between two photosensitizers (halogenated squaraines, i.e. Br-C4 and I-C4) and calf thymus DNA (ctDNA). Squaraines were found to bind ctDNA externally following a minor groove binding as they were able to replace Hoechst (a classic groove binder) from the groove of DNA. This binding mode was further supported by iodide quenching studies, ionic strength assay and Florescence Resonance Energy Transfer. Moreover, association (K_A) and dissociation (K_D) constants were obtained and compared with constants of well-known groove binders.

鱿鱼染料由于释放活性氧（ROS）并引起DNA损伤的能力而成为光动力疗法（PDT）中潜在的光敏剂。因此，至关重要的是评估和确定方脑与DNA之间的相互作用类型。

在这项研究中，使用了不同的光谱技术，例如UV-Vis和荧光光谱学，研究了两种光敏剂（卤代方脑，即Br-C4和I-C4）和小牛胸腺DNA（ctDNA）之间发生的相互作用类型。发现小分子在小沟结合后在外部结合ctDNA，因为它们能够从DNA沟中替代Hoechst（经典的沟结合物）。碘化物猝灭研究，离子强度测定和荧光共振能量转移进一步支持了这种结合模式。此外，获得了缔合常数（K _A）和解离常数（K _D），并将其与公知的沟槽粘合剂的常数进行比较。