Nanocarriers for drug delivery

1. A nanocarrier having an interior and an exterior, the nanocarrier comprising at least one conjugate having formula III:

Wherein

A is a polyethylene glycol (PEG) polymer;

each X is a monomer unit comprising a diaminocarboxylic acid;

X′ is a monomer unit selected from the group consisting of a diaminocarboxylic acid, an NH, and an O, optionally linked to a member selected from the group consisting of an optical probe, a radionuclide, a paramagnetic agent, a metal chelate and a drug; and

each R 2 is independently an amphiphilic compound having both a hydrophilic face and a hydrophobic face, wherein each amphiphilic compound is independently selected from the group consisting of cholic acid, allocholic acid, pythocholic acid, avicholic acid, deoxycholic acid, and chenodeoxycholic acid;

wherein each conjugate self-assembles in an aqueous solvent to form the nanocarrier such that a hydrophobic pocket is formed in the interior of the nanocarrier by the orientation of the hydrophobic face of each amphiphilic compound towards each other, and wherein the PEG of each conjugate self-assembles on the exterior of the nanocarrier.

2. The nanocarrier of claim 1 , wherein the nanocarrier further comprises a hydrophobic drug or an imaging agent, such that the hydrophobic drug or imaging agent is sequestered in the hydrophobic pocket of the nanocarrier.

3. The nanocarrier of claim 1 , wherein the diamino carboxylic acid is an amino acid.

4. The nanocarrier of claim 1 , wherein each diamino carboxylic acid is independently selected from the group consisting of 2,3-diamino propanoic acid, 2,4-diaminobutanoic acid, 2,5-diaminopentanoic acid (ornithine), 2,6-diaminohexanoic acid (lysine), (2-Aminoethyl)-cysteine, 3-amino-2-aminomethyl propanoic acid, 3-amino-2-aminomethyl-2-methyl propanoic acid, 4-amino-2-(2-aminoethyl) butyric acid and 5-amino-2-(3-aminopropyl) pentanoic acid.

5. The nanocarrier of claim 1 , wherein at least one of the monomer units is optionally linked to a member selected from the group consisting of an optical probe, a radionuclide, a paramagnetic agent, a metal chelate and a drug.

6. The nanocarrier of claim 2 , wherein the hydrophobic drug is selected from the group consisting of paclitaxel, SN38, camptothecin, etoposide and doxorubicin.

7. The nanocarrier of claim 1 , wherein

A is the polyethyleneglycol (PEG) polymer of 1-100 kDa, wherein A is optionally linked to a binding ligand L; and

each R 2 is cholic acid, wherein each cholic acid group is optionally substituted with 1-3 polyethyleneglycol (PEG) polymers each independently 200-10,000 Da in size.

8. The nanocarrier of claim 7 , the conjugate having formula Ma:

wherein

A is a PEG polymer of 5 kDa;

the monomer unit of X′ is lysine;

each X is lysine;

and each R 2 is cholic acid.