Compact multifunctional ligand to enhance colloidal stability of nanoparticles
A ligand design allows compact nanoparticle materials, such as quantum dots (QDs), with excellent colloidal stability over a wide range of pH and under high salt concentrations. Self-assembled biomolecular conjugates with QDs can be obtained which are stable in biological environments. Energy transfer with these ligands is maximized by minimizing distances between QDs/nanoparticles and donors/acceptors directly attached to the ligands or assembled on their surfaces.
1. A composition comprising:
a compound is selected from the group consisting of
wherein (A) is either
wherein each respective dashed line represents an amide bond, and wherein (B) and (C) are each independently selected from the group consisting of 2-hydroxyethyl, 3-carboxypropyl, 2-carboxyethyl, 2-aminoethyl, and 2-sulfoethyl.
2. The composition of claim 1 , further comprising a nanoparticle coated with said compound.
3. The composition of claim 2 , wherein:
(a) said nanoparticle is a quantum dot or a metallic nanoparticle;
(b) further comprising a cell penetrating peptide attached to the nanoparticle;
(c) said nanoparticle coated with said compound has a hydrodynamic diameter of less than 10 nm; or
(d) two or more of (a), (b), and (c).
4. The composition of claim 1 , wherein said compound comprises both a carboxyl group and a tertiary amine.
5. The composition of claim 1 , wherein said compound is selected from the group consisting of
6. The composition of Claim 1 , wherein said compound is selected from the group consisting of
7. The composition of claim 1 , wherein the compound is zwitterionic from pH 4 to pH 13.
8. A method of modifying a nanoparticle, the method comprising contacting the nanoparticle with a compound according to claim 1 .
9. The method of claim 8 :
(a) wherein said nanoparticle is a quantum dot or a metallic nanoparticle;
(b) further comprising attaching a cell penetrating peptide to the nanoparticle; or
(c) wherein said compound according to claim 1 comprises both a carboxyl group and a tertiary amine.
10. The method of claim 8 , wherein said compound is selected from the group consisting of
11. The method of claim 8 , wherein said compound is selected from the group consisting of
12. The method of claim 8 , wherein said nanoparticle coated with said compound has a hydrodynamic diameter of less than 10 nm.