Pyridyl Disulfide Functionalized Polymers as Nanotherapeutic Platforms

With the development of modern polymer synthesis techniques, polymer therapeutics have emerged and rapidly grown into a research hotspot and a promising tool for biomedical applications owing to their outstanding advantages in comparison to conventional drug therapy. Among an enormous number of polymers developed for therapeutic purposes, pyridyl disulfide (PD) group functionalized polymers have attracted increasing attention over the past decades. The highly reactive PD group could be replaced by almost any thiol-containing groups, leading to the production of a disulfide bond. More importantly, the redox-sensitive disulfide bond generated from the replacement can be exploited to develop stimuli-responsive polymer therapeutics which will protect the loaded cargoes from premature leakage, while programmably releasing them in response to endogenous redox stimuli such as glutathione. Herein, the development of PD-incorporated polymers and summarized PD-based monomers that have been synthesized to prepare various functional polymeric architectures are reviewed. Moreover, this review also discusses the difference between polymers with PD as repeating pendants or terminal groups and emphasizes on the diverse promising applications of these polymers as nanotherapeutic platforms in the biomedical field.