Nucleophile responsive charge-reversing polycations for pDNA transfection

Polycationic carriers promise low cost and scalable gene therapy treatments, however inefficient intracellular unpacking of the genetic cargo has limited transfection efficiency. Charge-reversing polycations, which transition from cationic to neutral or negative charge, can offer targeted intracellular DNA release. We describe a new class of charge-reversing polycation which undergoes a cationic-to-neutral conversion by a reaction with cellular nucleophiles. The deionization reaction is relatively slow with primary amines, and much faster with thiols. In mammalian cells, the intracellular environment has elevated concentrations of amino acids (similar to 10x) and the thiol glutathione (similar to 1000x). We propose this allows for decationization of the polymeric carrier slowly in the extracellular space and then rapidly in the intracellular milleu for DNA release. We demonstrate that in a lipopolyplex formulation this leads to both improved transfection and reduced cytotoxicity when compared to a non-responsive polycationic control.

Automated summary

Polycationic carriers have potential for low-cost and scalable gene therapy treatments, but their inefficient unpacking of genetic cargo limits transfection efficiency. Charge-reversing polycations offer targeted intracellular DNA release. We describe a new class of charge-reversing polycation that undergoes cationic-to-neutral conversion through a reaction with cellular nucleophiles. This allows for decationization of the carrier slowly in the extracellular space and rapidly in the intracellular milieu for DNA release, leading to improved transfection and reduced cytotoxicity.