Using a combined synthesis approach comprising reversible addition-fragmentation transfer polymerization and ring opening reaction, a series of poly glycidyl methacrylate (polyGMA) polymers were designed and synthesized for gene delivery. These polymers characterized by low cationic charge respective to established gene delivery vectors such as PEI were studied to further elucidate the key structure-activity parameters that mediate efficient and biocompatible gene delivery. Compared to PEI, these brushlike polymers facilitated markedly improved safety and gene delivery efficiency.