Development of Branched Poly(5-Amino-1-pentanol-co-1,4-butanediol Diacrylate) with High Gene Transfection Potency Across Diverse Cell Types

One of the most significant challenges in the development of polymer materials for gene delivery is to understand how topological structure influences their transfection properties. Poly(5-amino-1-pentanol-co-1,4-butanediol diacrylate) (C32) has proven to be the top-performing gene delivery vector developed to date. Here, we report the development of branched poly(5-amino-1-pentanol-co-1,4-butanediol diacrylate) (HC32) as a novel gene vector and elucidate how the topological structure affects gene delivery properties. We found that the branched structure has a big impact on gene transfection efficiency resulting in a superior transfection efficiency of HC32 in comparison to C32 with a linear structure. Mechanistic investigations illustrated that the branched structure enhanced DNA binding, leading to the formation of toroidal polyplexes with smaller size and higher cationic charge. Importantly, the branched structure offers HC32 a larger chemical space for terminal functionalization (e.g., guanidinylation) to further enhance the transfection. Moreover, the optimized HC32 is capable of transfecting a diverse range of cell types including cells that are known to be difficult to transfect such as stem cells and astrocytes with high efficiency. Our study provides a new insight into the rational design of poly(beta-amino ester) (PAE) based polymers for gene delivery.