Bottlebrush polymers with sequence-controlled backbones for enhanced oligonucleotide delivery

ABSTRACT The clinical translation of oligonucleotide-based thera-peutics continues to encounter challenges in delivery. In this study, we introduce a novel class of delivery vehicles for oligonucleotides, which are based on polyethylene glycol (PEG) bottlebrush polymers with sequence-defined backbones. Using solid-phase synthesis and bespoke phosphoramidites, the oligonucleotide and the polymer backbone can both be assembled on the solid support. The synthesis allows chemical modifiers such as carbon 18 (C 18 ) units to be incorporated into the backbone in specific patterns to modulate the cell-materials interactions. Subsequently, PEG side chains were grafted onto the polymer segment of the resulting polymer-oligonucleotide conjugate, yielding bottlebrush polymers. We report an optimal pattern of the C 18 modifier that leads to improved cellular uptake, plasma phar-macokinetics, biodistribution, and antisense activity in vivo. Our results provide valuable insights into the pacDNA structure-property relationship and suggest a possibility of tuning the polymer backbone to meet the specific delivery requirements of various diseases. Abstract Figure