Thermoreversibly assembled polymersomes for highly efficient loading, processing and delivery of protein and siRNA biologics

Versatile technologies that can deliver both RNA and protein payloads could streamline development, simplify manufacturing and expand the capabilities of combination therapies. Here we demonstrate an efficient approach to forming ca. 100 nm polymer vesicles (polymersomes) capable of rapid self-assembly without organic solvents, avoiding the need for post-encapsulation purification. Block copolymers are designed with a lower critical solution temperature that renders them soluble in aqueous medium under standard refrigeration, but they spontaneously assemble at room temperature into large batches of nanoparticles with predictable size and morphology. The nanomaterials are designed with charged and biofunctional moieties to drive payload affinity and in vivo targeting, while both siRNA and proteins can be encapsulated during warming at >75% loading efficiencies. Formulations can be stored in a dry state for greater hydrolytic stability under standard refrigeration and can be diluted directly from the vial, bypassing the need for purification required for high scalability. We use our system for in vivo delivery in protein subunit vaccination, immune tolerance induction and siRNA interference therapy in cancer.