Polyethylene glycol based oligomers for coating nanoparticles, nanoparticles coated therewith, and related methods
In a composition aspect of the invention, a nanoparticle coating comprises repeating polyacrylic acid monomers covalently bound together in an aliphatic chain having a plurality of carboxylic acid functional groups and modified carboxylic acid functional groups extending therefrom. A first portion of the modified carboxylic acid functional groups are modified by a PEG oligomer having a terminal methoxy functional group and a second portion of the modified carboxylic acid functional groups are modified by a PEG oligomer having at least one terminal sulfur moiety.
1. A composition comprising:
nanoparticles surface-capped with a coating composition, the coating composition comprising:
repeating polyacrylic acid monomer units covalently bound together in an aliphatic chain having a plurality of carboxylic acid functional groups and modified carboxylic acid functional groups extending therefrom, wherein a first portion of the modified carboxylic acid functional groups are modified by a PEG oligomer having a terminal methoxy functional group and a second portion of the modified carboxylic acid functional groups are modified by a PEG oligomer having at least one terminal sulfur moiety.
2. The composition of claim 1 , wherein the nanoparticles are coated by being directly bound to the at least one terminal sulfur moiety.
3. The composition of claim 1 , wherein the nanoparticles are selected from metallic nanoparticles, semiconductor nanoparticles, or a combination thereof.
4. The composition of claim 1 , wherein the nanoparticles are selected from gold nanoparticles, ZnS nanoparticles, CdSe nanoparticles, or a combination thereof.
5. The composition of claim 1 , wherein the at least one terminal sulfur moiety is formed from thioctic acid.
6. The composition of claim 1 , wherein the at least one terminal sulfur moiety is formed from dihydrolipoic acid.
7. The composition of claim 1 , wherein the PEG oligomer having a terminal methoxy functional group is formed from a Compound 2 having a structure:
wherein n has a value such that an average molecular weight of the PEG oligomer is about 750.
8. The composition of claim 1 , wherein the PEG oligomer having at least one terminal sulfur moiety is formed from a Compound 1 having a structure:
wherein n has a value such that an average molecular weight of the PEG oligomer is about 600.
9. The composition of claim 1 , wherein the PEG oligomer having a terminal methoxy functional group is formed from a Compound 2 and the PEG oligomer having at least one terminal sulfur moiety is formed from a Compound 1; wherein the Compound 2 and the Compound 1 have the following structures:
wherein n has a value such that an average molecular weight of the PEG oligomer is about 750; and
wherein n has a value such that an average molecular weight of the PEG oligomer is about 600.
10. The composition of claim 1 , wherein the PEG oligomer having at least one terminal sulfur moiety is formed from dihydrolipoic acid.
11. The composition of claim 1 , further comprising a third portion of modified carboxylic acid functional groups, wherein the third portion of the modified carboxylic acid functional groups are modified by a PEG oligomer having a terminal azide functional group.
12. The composition of claim 11 , wherein the PEG oligomer having at least one terminal sulfur moiety is formed from a Compound 1 having a structure:
wherein n has a value such that an average molecular weight of the PEG oligomer is about 600.
13. The composition of claim 1 , wherein a third portion of the modified carboxylic acid functional groups are modified by a PEG oligomer having a terminal amine functional group.
14. The composition of claim 13 , wherein the PEG oligomer having at least one terminal sulfur moiety is formed from dihydrolipoic acid.