Redox-responsive polymers for drug delivery: from molecular design to applications

Glutathione has been regarded as a significant signal for distinguishing between tumor and normal tissue. Recently, reactive oxygen species have attracted much attention for their close connection with many diseases. Taking advantage of the physiological signals, redox-responsive polymeric drug carriers constitute a significant research area in the various stimuli-responsive polymers for biomedical applications. During the rapid development of redox-responsive polymers, molecular design and related synthetic methodology plays a crucial role. In this review, we discuss the reduction- and oxidation-responsive polymeric drug carriers from the view of functional groups, as well as their applications in controlled release.