Synthesis and Properties of Sulfonium Polyelectrolytes for Biological Applications.

ABSTRACT

Sulfonium macromolecules displayed for the first time nucleic acid binding and transfection in vitro. Conventional and controlled radical polymerization techniques coupled with subsequent alkylation generated a sulfonium homopolymer, poly(DMSEMA), and a sulfonium diblock copolymer, poly(OEG-b-DMSEMA). DNA gel shift assays probed the ability of sulfonium macromolecules to complex nucleic acids, and luciferase assays examined the transfection efficiency and cytotoxicity of both sulfonium macromolecules. Poly(DMSEMA) and poly(OEG-b-DMSEMA) bound pDNA at a charge ratio of 1, and both induced significant luciferase expression in HeLa cells under serum-free conditions. Colloidal stability studies using dynamic light scattering highlighted the excellent colloidal stability of poly(OEG-b-DMSEMA) under salt and serum conditions due to the sterically stabilizing OEG block. Sulfonium macromolecules offer an alternate route to design cationic macromolecules for nonviral nucleic acid delivery, and future work will aim to add functionality to create more efficient delivery vehicles.