Development of simplified poly(β-aminoester)-zwitterion nanovehicles for transfection of cancer cells and improved gene delivery across a cell-based model of the blood-brain barrier

Although nucleotide-based therapeutics hold promise for a variety of diseases, their clinical application is limited because of low stability and poor bioavailability. Among non-viral gene delivery vectors, poly(β-aminoester)s (pBAEs) stand out because of their low cytotoxicity, high transfection capacity, and adequate biodegradation profile. Oligopeptide end-Modified pBAEs (OM-pBAEs) enable enhanced polynucleotide encapsulation, cellular internalization, and transfection. Despite the outstanding properties of OM-pBAEs as non-viral gene delivery vectors, traditional OM-pBAE formulations have low cell selectivity and require formulation with two or more polymers. In this study, we first develop a simplified OM-pBAE formulation with a single polymer (pBAE-CRHR) and then add a zwitterionic moiety as part of the end-capping process (pBAE-CRHR-Zw) to decrease unspecific transfection. Subsequently, we recover transfection capacity for target cancer cells in two ways: (i) by addition of a photo-cleavable moiety between the pBAE and the zwitterion, and (ii) by functionalization of pBAEs with BrainBike-4, a bicyclic peptidomimetic targeting the transferrin receptor 1. Finally, we show that derivatization of pBAE-CRHR-Zw with BrainBike-4 enhances transmigration of the gene delivery system across a tight monolayer of human endothelial cells mimicking the BBB.