Preparation and characterization of smart polymer brush-modified magnetic nanoparticles for biomedicine application

This paper investigates synthesis and characterization of smart polymer brush-modified magnetic nanoparticles (SPB-MNPs). Magnetic nanoparticles (MNPs) modified with poly(poly(ethylene glycol) monomethacrylate (poly(PEGMA)) brush were first functioned with activated pyridyldithio. Then, MNPs functioned with pyridyldithio (MNPs-PEG-PDT) were conjugated with 4-diamino-6-mercaptopyrimidine (DMP) to form SPB-MNPs via stimuli-responsive disulfide linkage. Fourier transform infrared spectra (FTIR) was used to monitor the preparation process of MNPs-PEG-PDT. MNPs-PEG-PDT is very highly reactive toward DMP. The disulfide linkage of SPB-MNPs can be cleaved by reduced glutathione (GHS). The concentration of GHS plays an important role in controlling the cleaved efficiency. The optimum concentration of GHS to release DMP is in the millimolar range.