Luminescent terphen[3]arene sulfate-activated FRET assemblies for cell imaging

Multicharged supramolecular assemblies based on luminescent macrocycle play an important role in extending their optical properties and functions. Herein, we reported macrocyclic supramolecular assemblies based on luminescent terphen[3]arene sulfate (TP[3]AS) and tetraphenylethylene pyridinium (TPE-4Py) through electrostatic interactions, host-guest encapsulation and π-π stacking interactions. Förster resonance energy transfer (FRET) process from STP3 to TPE-4Py was achieved with the energy transfer efficiency of 99.9%, accompanied by TPE-4Py fluorescence emission bathochromic shifted of 15 nm and enhanced by 1.68 times in PBS solution. In contrast, other non-luminescent sulfato-β-cyclodextrin and sulfobutylether-β-cyclodextrin only can enhance the fluorescence intensity of TPE-4Py without bathochromic shift. Due to the strong fluorescence and good stability of TPE-4Py@TP[3]AS, it can be used for optical imaging in living cells, which provided an effective approach for the construction of assemblling-confined luminescent biomaterials.