Charge-altering releasable transporters (CARTs) for the delivery and release of mRNA in living animals

Significance Protein expression using mRNA has the potential to transform many areas of life science research and affect the prevention, detection, and treatment of disease. However, realizing this potential requires the development of readily accessible, efficacious, and safe delivery systems that can functionally deliver mRNA to cells in culture and in vivo. A class of materials developed for mRNA delivery is described that operates through an unprecedented self-immolation mechanism. These materials are accessed in two steps through an organocatalytic oligomerization. They noncovalently complex, protect, deliver, and release mRNA with >99% transfection efficiency in cultured cells and with robust protein expression in mice using multiple routes of administration. This mRNA delivery technology should be broadly applicable to numerous research and therapeutic applications. Functional delivery of mRNA to tissues in the body is key to implementing fundamentally new and potentially transformative strategies for vaccination, protein replacement therapy, and genome editing, collectively affecting approaches for the prevention, detection, and treatment of disease. Broadly applicable tools for the efficient delivery of mRNA into cultured cells would advance many areas of research, and effective and safe in vivo mRNA delivery could fundamentally transform clinical practice. Here we report the step-economical synthesis and evaluation of a tunable and effective class of synthetic biodegradable materials: charge-altering releasable transporters (CARTs) for mRNA delivery into cells. CARTs are structurally unique and operate through an unprecedented mechanism, serving initially as oligo(α-amino ester) cations that complex, protect, and deliver mRNA and then change physical properties through a degradative, charge-neutralizing intramolecular rearrangement, leading to intracellular release of functional mRNA and highly efficient protein translation. With demonstrated utility in both cultured cells and animals, this mRNA delivery technology should be broadly applicable to numerous research and therapeutic applications.