Compositions and methods for delivery of nucleic acids

A composition comprising at least one lipid nanoparticle comprising at least one compound of Formula (I):

• or a salt thereof, wherein:
• each A is independently:
• each Z is —S—R1;
• each R1 is independently:
• each R2 or R3 is independently selected from hydrogen, C1-C6 alkyl, C1-C6 alkenyl, aralkyl, or hydroxyalkyl;
• each R4, R6 or R7 is independently selected from C1-C6 alkyl, C1-C6 alkenyl, or hydroxyalkyl;
• each R5 is independently hydrogen or C1-C6 alkyl;
• each X is independently halogen;
• each m is independently an integer independently selected from 1-10;
• each q is independently an integer independently selected from 1-200;
• each B is independently selected from:
• wherein each R is independently selected from hydrogen or C1-C6 alkyl;
• and C is:
• a. a C2-C100 hydrocarbon chain optionally containing one or more S atoms,
• b. CycA-L-CycB, wherein CycA and CycB are each independently a 5-8 membered cycloalkyl and L is C1-C3 alkylene,
• c. a polyalkylene oxide or polyalkylene oxide block copolymers of 200-5,000 molecular weight,
• d. an aliphatic or aromatic polyester of 200-5,000 molecular weight, or
• e. an aliphatic or aromatic polyurethane of 200-5,000 molecular weight;
• or
• wherein
• together form:
• wherein R8 is selected from C2-C6 alkyl, aryl,
• wherein t is an integer selected from 1-10;
• and
• wherein the at least one lipid nanoparticle further comprises at least one nucleic acid molecule.