Harnessing reactive oxygen species for advanced drug delivery and therapeutics.

Reactive oxygen species (ROS) have a unique position at the intersection of biology, chemistry, materials science, and medicine. They are indispensable mediators of physiological signalling, host defence, tissue remodelling, and cellular adaptation, yet their dysregulation is intimately associated with cancer, chronic inflammation, infection, metabolic disease, cardiovascular and cerebrovascular disorders, tissue injury, and ageing. This duality has made ROS both a therapeutic target and an attractive biological trigger for drug delivery. The Journal of Controlled Release Special Issue on "Harnessing Reactive Oxygen Species for Advanced Drug Delivery and Therapeutics" brings together a diverse collection of contributions that together present an important transition in the field. ROS-based delivery is moving beyond the conventional concept of a material that simply responds to an elevated oxidative environment. The contributions assembled here demonstrate that ROS can be scavenged, generated, amplified, buffered, spatially confined, chemically translated into drug release, coupled to immune modulation, integrated with metabolic sensing, and incorporated into theranostic and adaptive therapeutic systems.