Structurally defined polythiophene-based nanoprobe for selective Cu2+ detection in living cells

Structurally defined block conjugated polymers (SDBCPs) are characterized by unique photophysical and self-assembly properties. However, the potential of SDBCP for sensing application has seldomly been exploited. Herein, we present the synthesis and application of a novel type of SDBCP, P3EPT(17)-b-P3ImHT(33), which is comprised of regio-regular diblock polythiophene and imidazole side chains. P3EPT(17)-b-P3ImHT(33) can selfassemble into nanofibers in DMSO via crystallization-driven self-assembly, while it self-assembles into quasispherical micelles in water via hydrophilic/hydrophobic phase separation. By exploiting the strong coordination interaction between Cu2+ and imidazole group, P3EPT(17)-b-P3ImHT(33)-based nanoparticles (PT-CPNs) were used as an effective fluorescent nanoprobe for the selective and sensitive detection of Cu2+. The detection limit can be down to 0.13 nM. Furthermore, fluorescence imaging studies demonstrated that PT-CPNs can efficiently detect Cu2+ in living HeLa cells.

Automated summary

SDBCPs have unique photophysical and self-assembly properties, but their potential for sensing applications has been rarely explored. The novel SDBCP P3EPT(17)-b-P3ImHT(33) can self-assemble into nanofibers in DMSO and quasispherical micelles in water, and it has been utilized as a fluorescent nanoprobe for the selective and sensitive detection of Cu2+ with a detection limit as low as 0.13 nM. Moreover, fluorescence imaging studies have shown that PT-CPNs can effectively detect Cu2+ in living HeLa cells.