Alginate derivative-functionalized silica nanoparticles: surface modification and characterization

The bare silica nanoparticles (SiO NPs) synthesized by Stöber method is very hydrophilic and chemically inert, which may suffer from particles aggregation and low biocompatibility when they are used in physiological media. For this case, we attempted to conduct surface functionalization of SiO NPs by Ugi multicomponent reaction, using amphiphilic amidic alginate derivative (AAD) as the modifier. The successful synthesis of amidic alginate derivative-functionalized silica nanoparticles (AAD-SiO NPs) was confirmed by FT-IR spectroscopy, H NMR spectrometer, X-ray photoelectron spectroscopy and thermal gravimetric analysis. The covalent bonding of alginate derivative onto the surface of SiO NPs increased their average diameter and zeta potential, which effectively improved their colloidal stability in PBS. Additionally, surface tension measurements and cell studies results revealed that the resultant AAD-SiO NPs possessed relatively high surface activity and cytocompatibility, which exhibited great potential in the biomedical field.