摘要
Polymer-based conjugates are an interesting option and challenge for the design of nano-sized drug-delivery systems,as they require advanced conjugation chemistry and precise engineering.In the case of nucleic acid therapy,non-viral carriers face several biological barriers during the delivery process,namely 1)protection of the cargo from extracellular degradation,2)avoidance of non-specific interactions with non-targeted tissues,3)efficient entry into the target cells,4)intracellular trafficking to the site of action and 5)cargo release.To take on these obstacles,multifunctional conjugates can act as“smart polymers”with microenvironment-sensing dynamics to facilitate the separate delivery steps.Synthesis of defined polymer architectures with precise functionali-zation enables structure-activity relationships to be inves-tigated and the integration of key functions for efficient delivery.Thus bioresponsive polymer conjugates,which are equipped with molecular devices responding to the certain microenvironments within the delivery pathway(e.g.pH,redox potential,enzymes)can be assembled.This review focuses on the modular engineering and conjuga-tion of multifunctional polymeric structures for the utilization as“tailor-made”nucleic acid carriers.
