Unimolecular nanoparticles for efficient delivery of therapeutic RNA

1. A unimolecular nanoparticle and pharmaceutically acceptable salts thereof, wherein the unimolecular nanoparticle comprises a dendritic polymer core, cationic polymers, and outer poly(ethylene glycol) blocks, wherein the cationic polymers link the dendritic polymer core to the outer poly(ethylene glycol) blocks; and

wherein:

the dendritic polymer core has a molecular weight of about 500 to about 120,000 Da and terminating functional groups selected from the group consisting of-hydroxyl, amino, and carboxylic acid groups;

the cationic polymers are attached to at least 50% of the terminating functional groups of the dendritic polymer core via a pH-sensitive linker, wherein

the pH-sensitive linker comprises an imine, hydrazone, or cis-aconityl group; and

each cationic polymer comprises: a polymeric backbone, cationic functional groups, weakly basic groups, and disulfide bonds,

wherein:

 the polymeric backbone is a polyamide and is attached to the cationic functional groups and the weakly basic groups by the disulfide bonds;

 the cationic functional groups have a pKa of at least about 8 and are selected from the group consisting of primary amines, secondary amines, tertiary amines, amidines, guanidines, and combinations of two or more thereof;

 the molar ratio of the cationic functional groups to the weakly basic groups ranges from 1:1 to 5:1, and

 the cationic polymer has a molecular weight from about 1,000 to about 5,000 Da; and

the outer poly(ethylene glycol) blocks are attached to a plurality of the cationic polymers via ester, amide or ether groups and have a terminal group selected from the group consisting of a targeting ligand, OH, O—(C1-C6)alkyl, NH 2 , biotin, and a dye, wherein the poly(ethylene glycol) block has a molecular weight of about 1,000 to about 15,000 Da.

2. The unimolecular nanoparticle of claim 1 , wherein the cationic polymers comprise (C 2 -C 6 alkylene)disulfide(C 2 -C 6 alkyl)amino groups and/or salts thereof, and (C 2 -C 6 alkylene)disulfide(C 2 -C 6 alkyl)aminocarbonylimidazole groups and/or salts thereof.

3. The unimolecular nanoparticle of claim 1 , wherein the polymeric backbone is selected from the group consisting of polyasparagine, polyglutamine, polyornithine, and polylysine.

4. The unimolecular nanoparticle of claim 3 , wherein the cationic polymers comprise (C 2 -C 6 alkylene)disulfide(C 2 -C 6 alkyl)amino groups and/or salts thereof, and (C 2 -C 6 alkylene)disulfide(C 2 -C 6 alkyl)aminocarbonylimidazole groups and/or salts thereof.

5. The unimolecular nanoparticle of claim 1 , wherein the dendritic polymer core is a polyester or a poly(amido-amine).

6. The unimolecular nanoparticle of claim 1 , wherein the dendritic polymer core is a hyper-branched polymer or a dendrimer.

7. The unimolecular nanoparticle of claim 1 , wherein the dendritic polymer core has from 3 to 7 generations.

8. The unimolecular nanoparticle of claim 1 , wherein the dendritic polymer core is a poly(amido-amine) dendrimer having 3 to 4 generations.

9. The unimolecular nanoparticle of claim 1 , wherein the dendritic polymer core is a hyperbranched polyester having 3 to 4 generations.

10. The unimolecular nanoparticle of claim 1 , wherein the cationic polymer comprises a polyamide backbone, disulfide linkers, amino and/or ammonium salt groups, and imidazole and/or imidazolium salt groups.

11. The unimolecular nanoparticle of claim 10 , wherein the cationic polymers comprise

ethylene-disulfide-ethylamino groups and/or salts thereof, and

ethylene-disulfide-ethylaminocarbonylimidazole groups and/or salts thereof.

12. The unimolecular nanoparticle of claim 1 , wherein the targeting ligand is a cofactor, carbohydrate, peptide, antibody, nanobody, or aptamer.

13. The unimolecular nanoparticle of claim 1 , wherein the targeting ligand is selected from the group consisting of folic acid, mannose, GE11, cRGD, KE108, octreotide, TAT cell penetrating peptide, PSMA aptamer, TRC105, 7D12 nanobody, and CTB.

14. A complex comprising the unimolecular nanoparticle of claim 1 and a therapeutic RNA within the unimolecular nanoparticle.

15. The complex of claim 14 , wherein the therapeutic RNA is an siRNA.

16. The complex of claim 14 , wherein

the dendritic polymer core is a hyperbranched polyester having 3-4 generations and a molecular weight of about 3,600 to about 7,400 Da;

the pH-sensitive linker is a benzylimine;

each cationic polymer has a polyasparagine backbone attached to:

ethylene-disulfide-ethylamino and/or ethylene-disulfide-ethylammonium salt groups, and

ethylene-disulfide-ethylamidoimidazole and/or ethylene-disulfide-ethylamidoimidazolium salt groups;

wherein the ratio of the amino and/or ammonium salt groups to imidazole and/or imidazolium salt groups is from 1:1 to 5:1.

17. A composition comprising the unimolecular nanoparticle of claim 1 and a pharmaceutically acceptable carrier.

18. A kit comprising a package containing the unimolecular nanoparticle of claim 1 , a package containing an effective amount of siRNA, and directions for use of the kit.

19. A siRNA-loaded unimolecular nanoparticle comprising the unimolecular nanoparticle of claim 1 and a siRNA, wherein the loading of siRNA is about 10 wt % to about 20 wt %, based on the total siRNA-loaded unimolecular nanoparticle weight.

20. The unimolecular nanoparticle of claim 1 , wherein the cationic functional groups are selected from the group consisting of primary amines, secondary amines, tertiary amines, amidines, guanidines, and combinations of two or more thereof.

21. The unimolecular nanoparticle of claim 1 , wherein the weakly basic groups have a pKa of about 5.5 to about 7.0.

22. A method of preparing a complex comprising the unimolecular nanoparticle of claim 1 and a therapeutic RNA, the process comprising dispersing the therapeutic RNA within the unimolecular nanoparticle.

23. A method of treating a cancer by administering an effective amount of the complex of claim 14 , wherein the therapeutic RNA inhibits expression of a gene necessary for survival or growth of the cancer.