Synthesis and Characterization of Carboxyl-terminated Polyethylene Glycol Functionalized Mesoporous Silica Nanoparticles

Colloidal mesoporous silica nanoparticles functionalized with carboxy-terminated polyethylene glycol (CMS-PEG-COOH) were successfully synthesized by covalently grafting dicarboxy-terminated polyethylene glycol (HOOC-PEG-COOH) on the surface of the amino functionalized CMS nanoparticles with amide bond as a cross linker. Moreover, the structural and particle properties of CMS-PEG-COOH were characterized by nuclear magnetic resonance spectroscopy (1H-NMR), transmission electron microscopy (TEM), dynamic light scattering (DLS), nitrogen adsorption-desorption measurements, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The nanomaterials presented a relatively uniform spherical shape morphology with diameters of about 120 nm,and favorable dispersibility in weak acid solution. The CMS-PEG-COOH exhibited no changes in the state of amorphous, while the mesopores sizes of 5.25 nm might provide the nanomaterials with large capacity for the loading and releasing of drugs. So the results indicated that CMS-PEG-COOH might be a critical nanomaterial for drug delivery system in the future.