Graft-copolymer stabilized metal nanoparticles
There is provided a method of preparing nanoparticles and novel nanoparticles. The nanoparticle preparation comprises the generation of a mixture comprising a plurality of metal-containing compounds and a copolymer of a polyethylene glycol and an amine-containing polyamino acid such as polylysine where a metal core and polymer shell nanoparticle is formed. The novel nanoparticles have a metallic core and a graft copolymer shell of polyethylene glycol and an amine-containing polyamino acid where the shell least partially surrounds the metallic core and is non-ionically bound to the metallic core via metal-amine bonds.
1. A nanoparticle comprising:
a metallic core, and
a copolymer shell of a polyethylene glycol and an amine-containing polyamino acid that at least partially surrounds the metallic core,
wherein said copolymer shell is non-ionically bound to said metallic core via metal-amine bonds, and
wherein said nanoparticle is a non-aggregating nanoparticle, and
wherein said amine-containing polyamino acid is any of poly-L-lysine and poly-D-lysine.
2. The nanoparticle of claim 1 , wherein said nanoparticle has a Zeta potential in the range of about −14 to about +10 mV.
3. The nanoparticle of claim 1 , wherein said metallic core is about 5-25 nm in diameter and the nanoparticle has a hydrodynamic diameter in the range of about 10-100 nm.
4. The nanoparticle of claim 1 , wherein said polyethylene glycol comprises about 90-95% and said amine-containing polyamino acid comprises about 5-10% of said copolymer.
5. The nanoparticle of claim 1 , wherein said metallic core comprises gold.
6. The nanoparticle of claim 1 , wherein said metallic core comprises gold and one or more of platinum (II) and silver.
7. The nanoparticle of claim 1 , wherein said copolymer is acylated at the N-ε-amino.
8. The nanoparticle of claim 7 , wherein approximately 10-20% of the copolymer N-ε-amino groups are acylated.
9. The nanoparticle of claim 1 , wherein said polyethylene glycol is a methoxy polyethylene glycol (MPEG) or derivative thereof.
10. The nanoparticle of claim 9 , wherein said derivative of MPEG is an N-hydroxysuccinimide ester, imidazolide, a pentafluorophenyl ester, or an ethylthioacetate of MPEG or said derivative is O-Methyl(PEG))-O′-succinate.
11. The nanoparticle of claim 1 , wherein said copolymer has the structure:
wherein R 1 is hydrogen, a lower alkyl, or a protecting group and n is 20-220.
12. The nanoparticle of claim 1 , wherein at least about 50% of the copolymers in said shell are non-ionically bound to said metallic core via metal-amine bond.
13. The nanoparticle of claim 1 , wherein said copolymer shell covers at least about 50 percent of said metallic core.
14. The nanoparticle of claim 1 , wherein said copolymer shell covers at least about 75 percent of said metallic core.
15. The nanoparticle of claim 1 , wherein said copolymer shell covers at least about 80 percent of said metallic core.
16. The nanoparticle of claim 1 , wherein said copolymer shell covers at least about 90 percent of said metallic core.
17. The nanoparticle of claim 1 , further comprising an imaging or therapeutic moiety attached to said copolymer shell.
18. The nanoparticle of claim 1 , further comprising an imaging or therapeutic moiety that forms an ionic complex with said nanoparticle.
19. The nanoparticle of claim 18 , wherein said therapeutic moiety is a short negatively charged oligonucleotide or oligonucleotide duplex.