Ph Controlled Release Of Chromone From Chromone-fe_3o_4 Nanoparticles

摘要

Magnetic Fe_3O_4 nanoparticles (NPs) are promising as drug delivery vehicles for both diagnostic and therapeutic applications. The key to achieving these dual applications is that the drug-Fe_3O_4 NPs are stable in a biological circulation system, readily interact with cells or other biological units of interest, and are capable of releasing the drug once the selected targeting is realized. Currently, drug-Fe_3O_4 NP conjugates are made either by embedding the drug in the hydrophobic media in the double-layer coating of Fe_3O_4 NPs or by incorporating both drug and Fe_3O_4 NPs in the SiO_2 matrix. Although the conjugates prepared from these methods show enhanced dispersion stability, they have a hydrodynamic diameter of 150 nm or larger. Such large NP delivery systems may have very limited extravasation ability and may be subject to easy uptake by the reticuloendothelial system (RES), unsuitable for target-specific delivery applications. Recently we reported that Fe_3O_4 NPs coated with dopamine (DPA) and COOH-terminated polyethylene glycol (PEG) are stable in cell culture media against macrophage cell uptake. The hydrodynamic sizes of the NPs are tuned by the length of the PEG molecules. These PEG-DPA-Fe_3O_4 NPs offer an ideal platform for drug coupling and delivery.