Development of simplified, photo-active, and TfR1-targeted poly(β-aminoester)-zwitterion nanovehicles for gene delivery across brain endothelium

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). Subsequently, we show that addition of a photo-cleavable moiety enabled selective recovery of transfection capacity. Finally, we functionalize pBAE-CRHR-Zw with BrainBike-4, a bicyclic peptidomimetic binding transferrin receptor 1, and show that the targeted polyplexes display improved capacity to transfect cells with high levels of TfR1 and to transmigrate in a human cell-based model of the BBB.