1-(3-Aminopropyl)-4-methylpiperazine is a capping agent. The 1-(3-Aminopropyl)-4-methylpiperazine-capped Poly (beta-amino ester) (PBAE) poly (1,4-butanediol diacrylate-co-4-amino-1-butanol) undergoes electrostatic interactions with anionic molecules such as DNA and exhibits low cytotoxicity. The 1-(3-Aminopropyl)-4-methylpiperazine-capped Poly (1,4-butanediol diacrylate-co-4-amino-1-butanol) PBAE effectively delivers nucleic acids in various systems[1].