Development of Fluorescent Labels Based on Micelles of Triblock Copolymers Doped with D-π-A Architecture Dyes

The possibility of creating stable fluorescent labels based on triblock copolymers P123 and F127 doped with quinoxalinone derivatives of D-π-A architecture is considered. The hydrophobicity of the micellar core is shown to be the key factor determining dye encapsulation efficiency as well as colloidal and spectral stability. The more hydrophobic P123 demonstrates superior solubilization capacity for all examined dyes, forming monodisperse nanoparticles that remain stable for at least 5 days. In contrast, F127-based systems exhibit a tendency toward aggregation and the formation of large structures. In P123 micelles, homologous dyes display similar emission spectra, indicating a similar microenvironment and conformation, whereas in F127 micelles significant spectral differences are observed for the same dyes. The optimal dye–carrier pair is the P123@4 system, which exhibits high luminescence intensity, high colloidal and spectral stability over time, and resistance to bovine serum albumin (BSA). These results are important for the development of effective fluorescent labels and theranostic platforms based on triblock copolymer micelles.