Fig. 19. Examples of aggregated cyanine dye PS.

Certain cyanine dyes exhibit the propensity to self-assemble into nanostructures of specific sizes, influenced by their molecular structure or the presence of complementary cations (in this case of anionic cyanine dyes) for targeted tumor delivery. Notably, dyes 44 and 47 have the ability to form nanochains (approximately 50 nm) and nanoaggregates (around 200 nm in diameter), respectively, in contrast to 45 and 46. Compound 48 is a conjugate with indomethacin, serving as a binding partner for cyanine dyes and a cyclooxygenase inhibitor. Upon interaction with cyclooxygenase 2, the self-assembled nanoparticles of 48 undergo disassembly, leading to an augmented photodynamic efficiency. Furthermore, in the presence of dodecyl(triphenyl)phosphonium and metal ions (Fe²⁺ and Mn²⁺), anionic cyanine dyes (49 and 50, respectively) form nanoaggregates with significantly higher phototoxicity compared to the individual dyes.