Figure 1.

Formulation of functionalized polyplexes

The cationic lipo-OAA containing an N-terminal azido group was mixed with pDNA at N/P 12 and incubated for 30 min at room temperature (A). Following the addition of a DBCO agent with 0.25 equivalents, another incubation for 4 h at room temperature was performed (B). Schematic depictions are shown of the sequence-defined lipo-OAA with the compound ID 1252 (K, lysine; C, cysteine; Y, tyrosine; H, histidine; Stp, succinoyltetraethylene-pentamine) (C) and the structure of PEGylation agents for post-functionalization containing monovalent (D) or bivalent (E) DBCO with ligand peptide GE11 for targeting of EGFR or without GE11 as negative non-targeting control. DLS measurements of formed polyplexes revealed a size of 120–140 nm with a uniform size distribution (PDI of <0.2) (F) and a zeta potential below 20 mV, whereas non-targeted PEGylated polyplexes showed more efficient surface shielding than polyplexes with targeted ligands (G) (∗p ≤ 0.05; n/s, not significant). Results are reported as mean ± SEM (n = 3). RT, room temperature.