Water-dispersable nanoparticles
Provided herein are methods for making water-soluble nanoparticles comprising a core/shell nanocrystal that is coated with a surface layer comprising enough hydrophilic ligands to render the nanoparticle water soluble or water dispersable. Methods for crosslinking molecules on the surface of a nanoparticle, which methods can be used on the above water-soluble nanoparticles also are provided. Nanoparticle compositions resulting from these methods are also provided.
1. A population of water-dispersible nanoparticles, comprising:
a plurality of nanoparticles,
wherein each nanoparticle includes a nanocrystal core including a first semiconductor material, a shell including a second semiconductor material, and an outer layer that imparts hydrophilic properties to the nanoparticle,
wherein the outer layer is comprised of a plurality of hydrophilic peptide ligands and a plurality of phosphonic acid ligands each with at least one linking group for attachment to a surface of the shell,
wherein the ratio of the plurality of hydrophilic ligands to the plurality of phosphonic acid ligands is at least about 0.1:1.
2. The population of water-dispersible nanoparticles of claim 1 , wherein the phosphonic acid ligand is tetradecylphosphonic acid (TDPA) or octylphosphonic acid (OPA).
3. The population of water-dispersible nanoparticles of claim 1 , wherein the plurality of hydrophilic ligands are cross-linked to each other.
4. The population of water-dispersible nanoparticles of claim 1 , wherein the nanocrystal core is CdSe and the shell is ZnS.
5. A population of water-dispersible nanoparticles, comprising:
a plurality of nanoparticles, wherein each nanoparticle includes a nanocrystal core including a first semiconductor material, a shell including a second semiconductor material, and an outer layer that imparts hydrophilic properties to the nanoparticle,
wherein the outer layer is comprised of a plurality of tridentate thiol ligands and a plurality of phosphonic acid ligands each with at least one linking group for attachment to a surface of the shell,
wherein the ratio of the plurality of tridentate thiol ligands to the plurality of phosphonic acid ligands is at least about 0.5:1, wherein the tridentate thiol ligand is a compound of Formula I, II, III, IV, V, or VI:
wherein R 1 , R 2 , and R 3 , when taken alone, are independently H, halo, hydroxyl, (—(C═O)—C 1 -C 22 , —(C═O)CF 3 ,) alkanoyl, C 1 -C 22 alkyl, C 1 -C 22 heteroalkyl, ((CO)OC 1 -C 22 ) alkylcarbonato, or (—(CO)NH(C 1 -C 20 ) or —(CO)N(C 1 -C 20 ) 2 ) alkylcarbamoyl;
R 4 , and R 5 , when taken alone, are independently H, C 1 -C 20 alkyl, or C 6 -C 18 aryl; and
R 6 is H or a polyethylene glycol moiety.
6. The population of water-dispersible nanoparticles of claim 5 , wherein R 1 , R 2 , and R 3 are different.
7. The population of water-dispersible nanoparticles of claim 5 , wherein R 1 , R 2 , and R 3 are the same.
8. The population of water-dispersible nanoparticles of claim 5 , wherein R 4 and R 5 are different.
9. The population of water-dispersible nanoparticles of claim 5 , wherein R 4 and R 5 are the same.
10. The population of water-dispersible nanoparticles of claim 5 , wherein the polyethylene glycol moiety is a compound of Formula VII:
wherein R 7 is NH 2 , N 3 , NHBoc, NHFmoc, NHCbz, COOH, COOt-Bu, COOMe, iodoaryl, hydroxyl, alkyne, boronic acid, allylic alcohol carbonate, NHBiotin, CO)NHNHBoc, (CO)NHNHFmoc, or OMe,
wherein n is an integer from 1 to 100.
11. The population of water-dispersible nanoparticles of claim 5 , wherein the phosphonic acid ligand is one of TDPA or OPA.
12. The population of water-dispersible nanoparticles of claim 5 , wherein the nanocrystal core is CdSe and the shell is ZnS.