Recent advances in self-immolative linkers and their applications in polymeric reporting systems

Interest in self-immolative chemistry has grown over the past decade with more research groups harnessing the versatility to control the release of a compound from a larger chemical entity, given a specific stimulus. Originally conceived in 1981 to overcome electronic or steric features which may prohibit cleavage of a prodrug linkage; today's self-immolative linkers are widely used, inter alia, within medicinal chemistry, analytical chemistry, and material science. The incorporation of these linkers can be found in small molecules, dendritic and polymeric systems where a controlled release profile is required. This control can be of a binary character, release or not release, or a more nuanced issue of rate of release. In this article, we build upon our previous review in 2011 discussing key literature within the self-immolative field and, in particular, a selection of more recent examples that highlight how this field has matured in the past decade, with relevant earlier literature to provide context.