Making polymeric nanoparticles stimuli-responsive with dynamic covalent bonds

This review article highlights recent progress in the development of new polymeric nanoparticles which display stimuli-responsiveness on account of their incorporation of dynamic covalent bonds (DCBs). These bonds can form and cleave in response to changes in environmental parameters, such as pH or presence of reducing/oxidizing agents, and chemists have utilized this reversibility to make increasingly sophisticated stimuli-responsive polymeric nanoparticles. Another key feature of DCBs is their capacity to undergo component exchange processes involving the exchange for one reaction partner for another (for example, the reaction of an imine with an amine to produce a different imine and amine), which can present polymeric nanoparticles opportunities to modify their constitutions by reshuffling, incorporating or releasing components. The utilization of the responsive nature of DCBs presents an alternative approach towards stimuli-responsive polymeric nanoparticles which does not rely upon the utilization of ‘conventional’ stimuli-responsive polymers such as poly(N-isopropylpolyacrylamide). These new stimuli-responsive polymeric nanoparticles could find application in contemporary fields such as drug delivery or diagnostics, or within novel products in the established fields of paints, coatings and adhesives.