Compositions and methods for imaging and treatment

1. An iron oxide nanoparticle having a diameter from 5 nm to 15 nm and having adsorbed on the surface thereof a plurality of cucurbituril[7] (CB[7]) molecules, wherein the CB[7] molecules are adsorbed on the iron oxide nanoparticle surface via carbonyl groups of the CB[7] molecules and wherein each CB[7] molecule encloses a hydrophobic cavity.

2. The iron oxide nanoparticle of claim 1 , wherein one or more of the CB[7] molecules have at least a part of an active agent in the hydrophobic cavity.

3. The iron oxide nanoparticle of claim 2 , wherein the active agent is a hydrophobic or hydrophilic molecule.

4. The iron oxide nanoparticle of claim 3 , wherein the agent is a hydrophobic molecule selected from the group consisting of doxorubicin, cisplatin, paclitaxel, daunorubicin, alendronate, zoledronate and combinations thereof.

5. The iron oxide nanoparticle of claim 1 , wherein the CB[7] molecules are adsorbed on at least 70%, 80%, 90%, 95%, 99% of the total surface area of the iron oxide nanoparticle.

6. The iron oxide nanoparticle of claim 2 , wherein the active agent is a magnetic resonance imaging contrast agent.

7. A composition comprising a plurality of iron oxide nanoparticles of claim 1 in a carrier.

8. The composition of claim 7 , wherein the carrier is a buffer at a physiological pH.

9. The composition of claim 7 , where at least 70%, 80%, 90%, 95%, or 100% of the nanoparticles have a diameter of 8 nm to 10 nm.

10. The composition of claim 9 , wherein one or more of the CB[7] molecules on the nanoparticles have one or more active agents in the cavity thereof.

11. A method of making iron oxide nanoparticles of claim 1 comprising:

a) providing a plurality of iron oxide nanoparticles having a diameter of 5 nm to 15 nm in an aqueous medium;

b) contacting the iron oxide nanoparticles with at least an excess of CB[7] molecules such that a plurality of CB[7] molecules are adsorbed on to the surface of the iron nanoparticles;

c) separating the iron oxide nanoparticles having a plurality of CB[7] molecules chemisorbed on the surface thereof from free CB[7] molecules;

d) contacting the iron oxide nanoparticle from c) with an active agent to form iron oxide nanoparticles having CB[7] molecules adsorbed on the surface, wherein one or more of the CB[7] molecules have one or more active agents in the cavity thereof.

12. The method of claim 11 , wherein in step b), the number of molecules of CB[7] for each nanoparticle is at least 700.

13. The method of claim 12 , wherein in step b), the number of molecules of CB[7] for each nanoparticle is about 1,000.

14. The method of claim 11 , wherein the iron nanoparticles having a plurality of CB[7] molecules adsorbed on the surface thereof are separated from free CB[7] molecules by one or more washes with an aqueous solution.

15. The method of claim 11 , wherein step d) also comprises heating the reaction mixture of iron oxide nanoparticles and CB[7] molecules by exposing to microwave radiation.

16. A method of delivering an active agent to an individual comprising:

a) administering a composition of claim 7 to an individual;

b) optionally, guiding the nanoparticles in the composition to a desired location;

c) optionally, monitoring the transport of the nanoparticles;

d) exposing the individual to an alternating electric field such that at least a portion of the active agent is released at the desired location from the CB[7] molecules chemisorbed on the surface of the iron oxide nanoparticles.

17. The method of claim 16 , wherein the desired location comprises a tumor.

18. The method of claim 16 , further comprising obtaining imaging data on the individual after administering the composition and before exposing the individual to an alternating electric field to determine the movement and location of the nanoparticles.

19. The method of claim 16 , wherein the imaging data is obtained by magnetic resonance imaging.