Research Terms
Life Sciences Biochemistry Physical Sciences Chemistry
We have developed nanoparticle coatings that are water dispersible, have a strong affinity for binding to magnetic nanoparticles, and can be easily modified for attaching the coating to biological materials. The nanoparticle coatings comprise a polyacrylic acid based backbone onto which PEG-based oligomers are appended by modifying the native carboxyl groups of the PAA backbone. The PEG-based oligomers include functional groups on their terminal ends, which are chosen to provide a certain function. Some of the terminal functional groups bind the coatings to the nanoparticle's surface, while others provide reactive sites for binding other compounds to the coating. The method we developed for making these coatings allows one to tune the number and type of PEG-based oligomers appended to the PAA backbone based on the desired properties of the coating.
In accordance with a composition aspect of the invention, the nanoparticle coatings comprise 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 there from. 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 catechol group.
Professor Mattoussi developed polymer ligands that are optimally suited for surface-functionalizing magnetic nanoparticles. The amphiphilic polymers are prepared by coupling several amine-terminated anchoring groups, polyethylene glycol moieties, and reactive groups onto a poly(isobutylene-alt-maleic anhydride) (PIMA) chain. The reaction of maleic anhydride groups with amine-containing molecules is highly-efficient and occurs in one-step. The availability of several dopamine groups in the same ligand greatly enhances the ligand affinity, via multiple-coordination, to the magnetic NPs, while the hydrophilic and reactive groups promote colloidal stability in buffer media and allow subsequent conjugation with target biomolecules. Nanoparticles ligated with terminally reactive polymers have been easily coupled to target dyes and tested in live cell imaging with no measurable cytotoxicity.
A method for the photo-mediated phase transfer of inorganic nanocrystals, such as luminescent quantum dots, QDs, is provided. Irradiation, specifically UV excitation (?ex<400 nm), promotes the in-situ ligand exchange of hydrophobic quantum dots with hydrophilic ligands and their facile transfer to polar solvents and buffer media. The technique enables transfer of quantum dots and other nanocrystal materials from hydrophobic to polar and hydrophilic solutions.
