Ferroptosis Accompanied by ^•OH Generation and Cytoplasmic Viscosity Increase Revealed via Dual-Functional Fluorescence Probe

Abstract

Ferroptosis, a new form of regulated cell death, results from the iron-dependent accumulation of lipid peroxides that are associated with reactive oxygen species. However, it remains unclear how hydroxyl radical (^•OH) and cellular microenvironments such as viscosity alter in this process. Herein, we characterize for the first time the changing behavior of ^•OH and cytoplasmic viscosity during ferroptosis using a dual-functional fluorescence probe (H-V) that is designed via the molecular rotor strategy and the unique aromatic hydroxylation of ^•OH. Probe H-V shows completely separate spectral responses to ^•OH and viscosity with high sensitivity and selectivity, thereby achieving the detection of ^•OH and viscosity in two independent channels without spectral cross-interference. With the probe we find that ferroptosis is accompanied by significant ^•OH generation and cytoplasmic viscosity increase. Most notably, the raised ^•OH comprises the majority of the total reactive oxygen species in ferroptosis. H-V is biocompatible, ready to prepare, and may be expected to be used in the study of viscosity and ^•OH detection in more biosystems.