(A) The state-of-the-art approach of directly complexing mRNA with cationic carriers for mRNA delivery. When mRNA associates with cationic carriers, the poly-A tail may not be readily accessible to endogenous PABP due to steric hindrance. Upon release from the complex, however, mRNA is susceptible to degradation (deadenylase and exonucleases), resulting in poor expression of the desired protein. (B) Preassembly of mRNA/PABP nanoplexes with polyamines enhance mRNA translation via improvement of both mRNA stability and protein translation. (C) Molecular structures of polycation carriers used in this study. Note that amination of the backbone likely induces intramolecular isomerization of the repeating unit, aspartamide, generating two isomers.[19]