Intracellular protein delivery with a dimerizable amphiphile for improved complex stability and prolonged protein release in the cytoplasm of adherent cell lines

Direct delivery of functionally active proteins into cells represents an emerging strategy for laboratory investigation and therapeutic applications. For this purpose, we developed a novel amphiphile (CholCSper) consisting of cholesterol linked to carboxy-spermine by a cysteine. This amphiphile is dimerizable upon mild oxidation of the thiol to disulfide and it was used in formulation with DOPE to prepare an intracellular protein delivery system. The stabilization of the CholCSper assemblies by chemical conversion of CholCSper into its gemini amphiphile afforded the production of homogeneous assemblies with proteins whose sizes are easier to control. Furthermore, the cholesterol moiety has an effect on the density of the complexes formed with proteins and leads to a prolonged protein release in the cytoplasm of cells exposed to the protein carrier assemblies.