Advances in Fluorescence Techniques for the Detection of Hydroxyl Radicals near DNA and Within Organelles and Membranes.

Hydroxyl radicals (^•OH), the most potent oxidants among reactive oxygen species (ROS), are a major contributor to oxidative damage of biomacromolecules, including DNA, lipids, and proteins. The overproduction of ^•OH is implicated in the pathogenesis of numerous diseases such as cancer, neurodegenerative disorders, and some cardiovascular pathologies. Given the localized nature of ^•OH-induced damage, detecting ^•OH, specifically near DNA and within organelles, is crucial for understanding their pathological roles. The major challenge of ^•OH detection results from their short half-life, high reactivity, and low concentrations within biological systems. As a result, there is a growing need for the development of highly sensitive and selective probes that can detect ^•OH in specific cellular regions. This review focuses on the advances in fluorescence probes designed to detect ^•OH near DNA and within cellular organelles and membranes. The key designs of the probes are highlighted, with emphasis on their strengths, applications, and limitations. Recommendations for future research directions are given to further enhance probe development and characterization.