Gene delivery agents

A compound of Formula I:

• in which
• YA is H, C1-C4 alkyl, C2-C4 alkenyl, or C2-C4 alkynyl;
• ZA is C1-C30 amino, C1-C30 amido, C1-C30 carbonyl, C1-C30 carboxylate, diazolyl, or triazolyl, each of which is substituted with one or more of hydroxyl, C2-C20 carboxylate, hydroxyphenyl, C1-C10 phosphate, sugar, C1-C30 disulfanyl, ethylene glycol, or C4-C30 polyethylene glycol;
• ZB is
• each of LC or LD is CH2 or O;
• each of ZC and ZD, independently, is C1-C30 alkyl, C2-C30 alkenyl, or C2-C30 alkynyl;
• LK1 is C3-C8 alkylene or alkylene-heterocycloalkylene-alkylene;
• each of LK2, LK3, and LK4, independently, is a bond, C1-C8 alkylene, C2-C8 alkenylene, C2-C8 alkynylene, or alkylene-heterocycloalkylene-alkylene;
• and
• wherein the compound has 20 to 200 carbon atoms.