Smart polymeric nanocarriers for small nucleic acid delivery

In recent decades, nucleic acid therapeutics have been attracting much attention because of their potential as treatments for various diseases that require high target specificity. Nevertheless, the number of approved nucleic acid drugs is very limited due to substantially poor bioavailability, thereby generating the need for nucleic acid delivery carriers. A variety of delivery formulations have been reported so far. This review particularly describes polymer-based delivery carriers for systemic administration, highlighting the potential of biological environment-responsive chemistry for overcoming the biological barriers to nucleic acid delivery.