Controlled release behavior of pH-sensitive poly(2-(diethylamino)ethyl methacrylate)/palygorskite composite microspheres prepared via pickering emulsion polymerization

Abstract

(11.64 mM s) and GON-AN-FA (10.83 mM s) is much larger than that of the traditional positive MRI contrast agents, such as Magnevist (4.7 mM s). The results of cell viability assays indicate that the GON-AN and GON-AN-FA are almost non-cytotoxic. Furthermore, the specificities of GON-AN and GON-AN-FA were evaluated with two kinds of cancer cells that overexpress folate receptor alpha (FRα). The results reinforce that the GON-AN-FA is high-specifically-targetable to cancer cells via recognition of ligand FA and receptor FRα. In addition, the TEM and DLS results indicate that the SPION-AN-FA has a spherical shape, a uniform size and an excellent water-dispersibility (PDI b 0.05). The results of LSCM and flow cytometry demonstrate that the SPION-AN-FA is highly specific to MCF-7 and SPC-A1 cells due to the recognition of ligand FA and receptor FRα. The r1/r2 value of SPION-AN-FA is around 40, which is much higher than that of Resovist® indicating that our SPION-AN-FA has a stronger T2 shortening effect. The T2weighted images of MCF-7 cells incubated with SPION-AN-FA are significantly darker than those of MCF-7 cells incubated with AN, indicating that our SPION-AN-FA has a strong MR imaging efficacy.