Recent progress and advances in redox-responsive polymers as controlled delivery nanoplatforms

Stimuli-responsive polymeric nanosystems that can respond to biological stimuli such as pH, temperature, glucose, enzymes or redox conditions have been extensively explored for different biomedical applications. Among these, redox conditions should be the most useful stimulus in biological systems, which rely on the significantly different redox states in the circulation/ extracellular fluids and intracellular compartments. By incorporation of redox-responsive linkages such as disulfide and diselenide into polymers, different redox-responsive polymeric nanosystems can be fabricated. In this review article, a number of redox-responsive polymeric therapeutic nanosystems and their design principles are included. Recent advances in these redox-responsive polymeric therapeutic nanosystems for controlled cytoplasmic delivery of a number of bioactive molecules (e. g. drugs, biological proteins, plasmid DNA, siRNA) are also highlighted. This review will provide useful information for the design and biomedical applications of redox-responsive polymeric therapeutic nanosystems, which will attract great research interest from scientists in chemistry, materials, biology, medicine and interdisciplinary areas.