a, RNA is loaded into hydrogel either with no manipulation (naked RNA) or by means of nanocarriers. b, RNA-loaded hydrogels can be used as implantable scaffolds or as injectable gels for local RNA delivery. The fine-tunable physical, biochemical and biological features of hydrogels allow the sustained and/or controllable release of RNA. Upon cellular entry (for example, via naked RNA or RNA-loaded nanocarriers), RNA reaches the proper subcellular compartment to initiate protein production/inhibition.