Phthalocyanine conjugates with nucleosides and nucleic acids: synthetic strategies, photophysical properties, and biomedical applications.

Phthalocyanines are promising second-generation photosensitizers because of their strong red and near-infrared absorption, high photostability, and efficient singlet oxygen generation. However, their biomedical use is often limited by poor aqueous solubility, aggregation, and limited selectivity for diseased tissues. Conjugation with nucleosides and nucleic acids offers an effective strategy to address these limitations while adding biologically relevant recognition and targeting functions. This review summarizes phthalocyanine conjugates containing nucleobases, nucleosides, oligonucleotides, and related nucleic acid-derived structures, with emphasis on their synthetic methods, photophysical behavior, and biological applications. The discussion highlights how these conjugates influence aggregation, absorption, fluorescence, photoinduced electron transfer, triplet-state formation, reactive oxygen species generation, cellular uptake, and nucleic acid recognition. Recent advances in their synthetic strategies, photophysical properties, and biomedical applications are also considered. Collectively, these studies show that nucleobase-, nucleoside-, and oligonucleotide-based conjugation broadens the physicochemical and biological scope of phthalocyanines and strengthens their potential in precision photomedicine.