Oxidation-Responsive Materials: Biological Rationale, State of the Art, Multiple Responsiveness, and Open Issues

In this review, a general introduction to biological oxidants (focusing on reactive oxygen species, ROS) and the biomedical rationale behind the development of materials capable of responding to ROS is provided. The state of the art for preparative aspects and mechanistic responses of the most commonly used macromolecular ROS-responsive systems, including polysulfides, polyselenides, polythioketals, polyoxalates, and also oligoproline- and catechol-based materials, is subsequently given. The endowment of multiple responsiveness, with specific emphasis on the cases where a molecular logic gate behavior can be obtained, is focused on. Finally, fundamental open issues, which include implications of the "drug"-like character of ROS-responsive materials (inherent anti-inflammatory behavior) and the poor quantitative understanding of ROS roles in biology, are discussed.