Figure 1. Polymer synthesis and screening strategy.

(a) Synthesis scheme of acrylate-terminated poly(β-amino ester)s (PBAE) base polymer, (b) conventionally end-capped ePBAEs, (c) poly(ethylene glycol)-co-poly(β-amino ester)s (PEG-PBAEs), and (d) monomers used in the synthesis of a library of PBAE-based polymers. (e) Workflow diagram of ePBAE and PEG-PBAE screening process for identification of the most optimal PEG-PBAE NP formulation.