Tunable luminescence of hyperbranched polysiloxanes by nonsaturation-induced electrostatic potential polarization for activatable fluorescent theranostics.

Developing high-efficiency luminescent polysiloxanes with activatable fluorescent theranostics is highly desirable in biomedicine. In this work, we compared hyperbranched polysiloxanes (HBPSis) with diverse nonsaturation and built an intelligent chemodynamic therapy (CDT) system with activatable fluorescence imaging. Experimental characterization and theoretical calculations reveal that increased nonsaturation offers numerous delocalized π electrons to modulate the polarization of electrostatic potential, which further drives the clusterization of carbonyl groups. Consequently, through-space interactions are enhanced, leading to a red-shifted emission and improved quantum yield. Furthermore, an intelligent CDT system, HBPSi-Fe@AT, is fabricated. Both the CDT process and fluorescence imaging can be activated in the presence of overexpressed glutathione. This work provides fresh insight into nonsaturation-induced electrostatic potential polarization and presents an activatable CDT system for versatile fluorescence imaging-guided theranostics.